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HomeMy WebLinkAbout1/26/2016 - RegularRoanoke County Board of Supervisors January 26, 2016 NOTE: There will not be a 7:00 p.m. evening session as no public hearings are scheduled. INVOCATION: PLEDGE OF ALLEGIANCE TO THE UNITED STATES FLAG Disclaimer: "Any invocation that may be offered before the official start of the Board meeting shall be the voluntary offering of a private citizen, to and for the benefit of the Board. The views or beliefs expressed by the invocation speaker have not been previously reviewed or approved by the Board and do not necessarily represent the religious beliefs or views of the Board in part or as a whole. No member of the community is required to attend or participate in the invocation and such decision will have no impact on their right to actively participate in the business of the Board." Page 1 of 5 Roanoke County Board of Supervisors Agenda January 26, 2016 Good afternoon and welcome to our meeting for January 26, 2016. Regular meetings are held on the second and fourth Tuesday at 3:00 p.m. Public hearings are held at 7:00 p.m. on the fourth Tuesday of each month. Deviations from this schedule will be announced. The meetings are broadcast live on RVTV, Channel 3, and will be rebroadcast on Thursday at 7:00 p.m. and on Saturday at 4:00 p.m. Board of Supervisors meetings can also be viewed online through Roanoke County's website at www.RoanokeCountyVA.gov. Our meetings are closed -captioned, so it is important for everyone to speak directly into the microphones at the podium. Individuals who require assistance or special arrangements to participate in or attend Board of Supervisors meetings should contact the Clerk to the Board at (540) 772-2005 at least 48 hours in advance. Please turn all cell phones off or place on silent. A. OPENING CEREMONIES (3:00 p.m.) 1. Roll Call B. REQUESTS TO POSTPONE, ADD TO OR CHANGE THE ORDER OF AGENDA ITEMS C. PROCLAMATIONS, RESOLUTIONS, RECOGNITIONS AND AWARDS 1. Recognition of the Roanoke County Police Department and Emergency Communications Center for receiving re -accreditation through the Commission on Accreditation for Law Enforcement Agencies, Inc. (CALEA) (Susan A. Slough, Assistant Director of Comm unications/CommIT; Howard B. Hall, Chief of Police) 2. Resolution expressing the appreciation of the Board of Supervisors of Roanoke County to Woodrow Henderson, Volunteer Fire Chief of Fort Lewis Fire Department, upon his retirement after forty (40) years of service (Stephen Simon, Chief of Fire and Rescue) 3. Recognition of the Roanoke County Sheriff Department for receiving re- accreditation status with the American Correctional Association (ACA) (J. Eric Orange, Sheriff) Page 2 of 5 D. BRIEFINGS 1. Presentation of the proposed Capital Improvement Program (CIP) for fiscal year 2017-2026 (Thomas C. Gates, County Administrator; Christopher Bever, Director of Management and Budget) 2. Briefing to update the Board of Supervisors on Virginia Department of Transportation House Bill 2 Projects (Richard L. Caywood, Assistant County Administrator) E. NEW BUSINESS 1. Resolution establishing an Audit Committee of the Board of Supervisors of Roanoke County (Tanya Catron, Internal Auditor) 2. Request to approve the Amended and Restated New River Valley Commerce Park Participation and Revenue Sharing Agreement (Jill Loope, Director of Economic Development) F. FIRST READING OF ORDINANCES Ordinance amending Article IV. -Self -Insurance Program, Section 2-83 of the County Code clarifying the current practice that Fire and Rescue volunteers are covered under Worker's Compensation, and that other volunteers remain covered under a Blanket Accident Policy and/or General Liability Policy (Daniel R. O'Donnell, Assistant County Administrator) G. SECOND READING OF ORDINANCES 1. Ordinance amending Section 2-115 "Rules of Debate" of the Roanoke County Code to provide for the requirement of a "Second" for all motions before debate at the Board of Supervisors Meetings (Requested by Supervisor Joseph P. McNamara) H. APPOINTMENTS 1. Board of Zoning Appeals (BZA) (appointed by District) 2. Budget and Fiscal Affairs Committee (BFAC) (appointed by District and At Large) 3. Clean Valley Council (At Large) 4. Economic Development Authority (EDA) (appointed by District) 5. Parks, Recreation and Tourism Advisory Commission (appointed by District) Page 3 of 5 CONSENT AGENDA ALL MATTERS LISTED UNDER THE CONSENT AGENDA ARE CONSIDERED BY THE BOARD TO BE ROUTINE AND WILL BE ENACTED BY ONE RESOLUTION IN THE FORM OR FORMS LISTED BELOW. IF DISCUSSION IS DESIRED, THAT ITEM WILL BE REMOVED FROM THE CONSENT AGENDA AND WILL BE CONSIDERED SEPARATELY 1. Approval of minutes — October 27, 2015 2. Request to accept and allocate grant funds in the amount of $9,268 to the Clerk of the Circuit Court from the Commonwealth of Virginia for fiscal year 2015/2016 3. Donation of a Police Dog to the Roanoke County Police Department 4. Confirmation of appointments to Court -Community Corrections Alcohol Safety Action Program (ASAP) Policy Board; Court -Community Corrections Program — Regional Community Criminal Justice Board; Roanoke Valley -Alleghany Regional Commission (Regional Stormwater Management Committee), Roanoke Valley Transportation Planning Organization, Roanoke Valley - Alleghany Regional Commission, Social Services Board, Virginia Association of Counties, Virginia's First Regional Industrial Facility Authority and Western Virginia Regional Jail Authority J. CITIZENS' COMMENTS AND COMMUNICATIONS K. REPORTS 1. General Fund Unappropriated Balance 2. Capital Reserves 3. Reserve for Board Contingency 4. Outstanding Debt 5. Accounts Paid — December 31, 2015 6. Comparative Statement of Budgeted and Actual Revenues as of December 31, 2015 7. Comparative Statement of Budgeted and Actual Expenditures and Encumbrances as of December 31, 2015 Page 4 of 5 8. Treasurer's Statement of Accountability per Investment and Portfolio Policy as of December 31, 2015 L. REPORTS AND INQUIRIES OF BOARD MEMBERS 1. Al Bedrosian 2. Martha B. Hooker 3. Joseph P. McNamara 4. George G. Assaid 5. P. Jason Peters M. WORK SESSIONS 1. Work session to discussion an Amendment to the Erosion and Sediment Control Ordinance, Stormwater Management Ordinance and Design Manual and proposed Memorandum of Understanding with the Town of Vinton (Arnold Covey, Director of Community Development) 2. Work session to review with the Board of Supervisors the mid -year fiscal year 2015-2016 revenues and expenditures (Christopher Bever, Director of Management and Budget) N. ADJOURNMENT Page 5 of 5 ACTION NO. ITEM NO. C-1 AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER MEETING DATE: January 26, 2016 AGENDA ITEM: Recognition of the Roanoke County Police Department and Emergency Communications Center for receiving re- accreditation through the Commission on Accreditation for Law Enforcement Agencies, Inc. (CALEA) SUBMITTED BY: Susan A Slough Assistant Director for Comm unications/CommIT Howard B Hall Chief of Police APPROVED BY: Thomas C. Gates County Administrator COUNTY ADMINISTRATOR'S COMMENTS: SUMMARY OF INFORMATION: In November 2015, the Roanoke County Police Department and Emergency Communications Center (ECC) underwent an Agency Review for reaccreditation through the Commission on Accreditation for Law Enforcement Agencies, Inc. (CALEA). After review, both the Roanoke County Police Department and ECC were accredited. The accreditation process provides the community the confidence that the public safety agencies serving them demonstrate nationally established professional standards. Specific goals of the process are to strengthen crime prevention and control capabilities, formalize essential management procedures, establish fair and nondiscriminatory personnel practices, improve service delivery, solidify interagency cooperation and coordination, and provide agencies the opportunity to re-evaluate departmental goals, objectives, and resource use. This is the eighth (8t") time the Police Department has met the requirements for accreditation through CALEA and the third (3rd) time for the ECC. Reaccreditation is valid for a period of four (4) years. Page 1 of 1 ACTION NO. ITEM NO. C-2 AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER MEETING DATE: January 26, 2016 AGENDA ITEM: Resolution expressing the appreciation of the Board of Supervisors of Roanoke County to Woodrow Henderson, Volunteer Fire Chief of Fort Lewis Fire Department, upon his retirement after forty (40) years of service SUBMITTED BY: Stephen Simon Chief of Fire and Rescue APPROVED BY: Thomas C. Gates County Administrator COUNTY ADMINISTRATOR'S COMMENTS: SUMMARY OF INFORMATION: This time has been set aside to recognize and thank Mr. Henderson for his service to Roanoke County. STAFF RECOMMENDATION: Staff recommends adoption of the attached resolution. Page 1 of 1 AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA, HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER ON TUESDAY, JANUARY 26, 2016 RESOLUTION EXPRESSING THE APPRECIATION OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY TO WOODROW HENDERSON, VOLUNTEER FIRE CHIEF OF FORT LEWIS FIRE DEPARTMENT, UPON HIS RETIREMENT AFTER FORTY (40) YEARS OF SERVICE WHEREAS, Chief Henderson joined Fort Lewis Fire Department in September 1975; and WHEREAS, Chief Henderson retired on January 1, 2016, after forty (40) years of devoted, faithful and expert service to Roanoke County; and WHEREAS, during his time serving Roanoke County, Chief Henderson, rose through the ranks serving as a firefighter, lieutenant, assistant chief and then most recently as chief for the past twenty-three (23) years; and WHEREAS, Chief Henderson became the fourth (4t") Chief of the Fort Lewis Fire Department in 1993; and WHEREAS, Chief Henderson served on a number of noteworthy boards including: the Roanoke County Chiefs Board for twenty-nine (29) years, Chairman of the Roanoke County Fire Chiefs Board for most of his twenty-three (23) years as Chief, member of the Virginia State Firefighters Association for thirty (30) years and member of the Virginia State Fire Chiefs Association for twenty-four (24) years, served on the LOSAP/VIP Board of Trustees for more than fifteen (15 ) years; and twenty (20) years on the Virginia Association of Hazardous Materials Response; and WHEREAS, Chief Henderson also held a number of certifications while volunteering including: Page 1 of 2 • Firefighter 1, 2 & 3 • Fire Instructor 1, 2 & 3 • Fire Officer 1 & 2 • Confined Space • Trench • Rope 1 & 2 • Hazardous Materials Awareness, Operations, Technician, Specialist & Instructor • Ariel Operator & Instructor • Emergency Vehicle Operations Course & Instructor • Highway Safety Management WHEREAS, Chief Henderson also taught firefighter certification classes in many of the above subject matters for forty (40) years to an estimated six thousand (6,000) students; and WHEREAS, Chief Henderson served with, supervised, trained and mentored over two hundred (200) volunteer firefighters since 1975; and WHEREAS, Chief Henderson served during many memorable incidents including mountain fires, water rescues, train derailments and the December 19, 2009, historic snowfall that resulted in sixteen (16) inches of snow, which paralyzed traffic and stranded sixty-three (63) motorists, who were shuttled to the Fort Lewis Station to stay overnight. NOW, THEREFORE, BE IT RESOLVED that the Board of Supervisors of Roanoke County expresses its deepest appreciation and the appreciation of the citizens of Roanoke County to Woodrow "Woody" Henderson for forty (40) years of capable, loyal, and dedicated service to Roanoke County; and FURTHER, the Board of Supervisors does express its best wishes for a happy and productive retirement. Page 2 of 2 FURTHER, the Board of Supervisors does express its best wishes for a happy and productive retirement. Page 3 of 3 ACTION NO. ITEM NO. C-3 AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER MEETING DATE: January 26, 2016 AGENDA ITEM: Recognition of the Roanoke County Sheriff Department for receiving re -accreditation status with the American Correctional Association (ACA) SUBMITTED BY: APPROVED BY: J. Eric Orange Sheriff Thomas C. Gates County Administrator COUNTY ADMINISTRATOR'S COMMENTS: SUMMARY OF INFORMATION: On August 17, 2015, the Roanoke County Sheriff's Office was notified by the American Corrections Association (ACA) of their re -accreditation receiving an exemplary review score of 99.31. The re -accreditation process is performed every three (3) years at which time the agency seeking accreditation is evaluated based on 383 operational standards of performance as established by ACA. Re -accreditation requires a daily commitment to ensuring standards are met and maintained. Sheriff Orange specifically would like to recognize the contributions of Sgt. Denise Ory and Ms. Holly Jones for their efforts to secure re -accreditation for the Sheriff's Office. Both Sgt. Ory and Ms. Jones have been recognized by the ACA review board for their role in implementing an electronic filing system, the first implementation of its type in the Commonwealth. Their effective implementation of this system allowed the re -accreditation review to be conducted in record time. In addition to Sgt. Ory and Ms. Jones, Sheriff Orange recognizes former Sheriff Charlie Poff as the Department Head responsible for oversight of the re -accreditation process and commends all those involved for their hard work and dedication in seeing this process through to a successful completion. Page 1 of 1 ACTION NO. ITEM NO. D-1 AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER MEETING DATE: January 26, 2016 AGENDA ITEM: Presentation of the proposed Capital Improvement Program (CIP) for fiscal year 2017-2026 SUBMITTED BY: Thomas C. Gates County Administrator Christopher Bever Director of Management and Budget APPROVED BY: Thomas C. Gates County Administrator COUNTY ADMINISTRATOR'S COMMENTS: SUMMARY OF INFORMATION: This time has been scheduled to provide the Board of Supervisors with a briefing on the County Administrator's proposed fiscal year 2017-2026 Capital Improvement Program (CIP). The proposed Capital Improvement Program document and the presentation, which will provide an overview of the CIP will be distributed to the Board of Supervisors at the January 26, 2016 meeting. Page 1 of 1 ACTION NO. ITEM NO. D-2 AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER MEETING DATE: January 26, 2016 AGENDA ITEM: Briefing to update the Board of Supervisors on Virginia Department of Transportation House Bill 2 Projects SUBMITTED BY: Richard L. Caywood Assistant County Administrator APPROVED BY: Thomas C. Gates County Administrator COUNTY ADMINISTRATOR'S COMMENTS: SUMMARY OF INFORMATION: Staff will provide to the Board of Supervisors a briefing on Virginia Department of Transportation House Bill 2 projects. The attached PowerPoint presentation will be reviewed. 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ITEM NO. E-1 AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER MEETING DATE: January 26, 2016 AGENDA ITEM: Resolution establishing an Audit Committee of the Board of Supervisors of Roanoke County SUBMITTED BY: Tanya Catron Internal Auditor APPROVED BY: Thomas C. Gates County Administrator COUNTY ADMINISTRATOR'S COMMENTS: SUMMARY OF INFORMATION: The purpose of the audit committee is to serve as a liaison between the Roanoke County Board of Supervisors and staff. The audit committee has the responsibility to assist the Board in carrying out its policy setting role as it relates to financial and reporting practices, internal control, compliance with policies and reliance on the work of independent auditors. During the mid -1980's, Roanoke County created an audit committee pursuant to Roanoke County, Virginia Code Section 2-146 Creation of Committees, Boards and Commissions. Although the committee was established, the committee's responsibilities, organization and member appointment were not formally defined by resolution or ordinance. The formation of the County's internal audit function prompts formal establishment of the Audit Committee and definition of responsibilities, organization and member appointment. Staff proposes the Audit Committee be comprised of two Board of Supervisor members appointed by the Board for a one year term commencing January of each year. Audit Committee members appointed by the Board may not act for or bind the Board unless authorized to so by specific Board action. It is expected the audit committee will meet a minimum of three (3) times annually for the following purpose(s): • To advise the Internal Auditor and County Administrator on responsibilities and obligations for the Internal Auditor as defined by the Internal Audit Charter (Draft attached); Page 1 of 2 • To advise and comment on the annual Internal Audit Plan to be implemented by the Internal Auditor; • To advise and comment on the budget and resource requirements of the Internal Auditor necessary to carry out assigned responsibilities; • To receive communications from the Internal Auditor on activities and performance relative to the Internal Audit Plan; • To receive communications from the independent external auditors related to the annual financial statements audit; and • To make inquiries of the Internal Auditor. FISCAL IMPACT: •OM STAFF RECOMMENDATION: Staff recommends approving the resolution establishing an Audit Committee of the Board of Supervisors. Page 2 of 2 AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA, HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER ON TUESDAY, JANUARY 26, 2016 RESOLUTION ESTABLISHING AN AUDIT COMMITTEE OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY WHEREAS, during the mid -1980's Roanoke County created an audit committee pursuant to Roanoke County, Virginia Code Section 2-126 Creation of Committees, Boards and Commissions; and WHEREAS, the audit committee was established, the committee's responsibilities, organization and member appointment were not formally defined by resolution or ordinance; and WHEREAS, the formation of the County's internal audit function prompts formal establishment of the audit committee and the committee's definition of responsibilities, organization and member appointment; and WHEREAS, the purpose of the audit committee is to serve as a liaison between the Roanoke County Board of Supervisors and staff; and WHEREAS, the audit committee has the responsibility to assist the Board in carrying out its policy setting role as it relates to financial and reporting practices, internal control, compliance with policies and reliance on the work of independent auditors; and WHEREAS, the audit committee will be comprised of two Board of Supervisor members appointed by Board for a one (1) -year term commencing January of each year; and Page 1 of 2 WHEREAS, audit committee members appointed by the Board may not act for or to bind the Board unless authorized by specific Board action; and WHEREAS, the audit committee will meet a minimum of three (3) times annually for the following purpose(s): (i) to advise the Internal Auditor and County Administrator on responsibilities and obligations for the Internal Auditor as defined by the Internal Audit Charter; (ii) to advise and comment on the annual Internal Audit Plan to be implemented by the Internal Auditor; (iii) to advise and comment on the budget and resource requirements of the Internal Auditor necessary to carry out assigned responsibilities; (iv) to receive communications from the Internal Auditor on activities and performance relative to the Internal Audit Plan; (v) to receive communications from the independent external auditors related to the annual financial statements audit; and (vi) to make inquiries of the Internal Auditor. NOW, THEREFORE, BE IT RESOLVED by the Roanoke County Board of Supervisors of Roanoke Virginia, the audit committee is officially established and that: 1. The Committee is to serve as liaison between the Roanoke County Board of Supervisors and staff and to assist the Board carry out its oversight role; 2. The Committee will be comprised of two Board of Supervisor members appointed by Board for a one year term commencing January of each year; 3. The Committee members appointed by the Board may not act for or to bind the Board unless authorized by specific Board action; 4. The Committee will meet a minimum of three (3) times annually; and 5. This resolution is effective immediately. Page 2 of 2 z � *13 z 1838 INTERNAL AUDIT CHARTER Effective January _, 2016 INTRODUCTION: Internal auditing is an independent and objective assurance and consulting activity that is guided by a philosophy of adding value to improve the operations of the County of Roanoke (hereafter referred to as the County). It assists the County in accomplishing its objectives by bringing a systematic and disciplined approach to evaluate and improve the effectiveness of the County's governance, risk management and internal control. ROLE: The internal audit activity is established by the County Administrator in consultation with the Audit Committee. The internal audit activity's responsibilities are defined by the County Administrator. PROFESSIONAL STANDARDS: AhOrx The internal audit activity will perform audits in accordance with Generally Accepted Government Auditing Standards (hereafter referred to as GALAS). These standards are issued by the Comptroller General of the United States in conjunction with the Government Accountability Office. GAGAS was established to guide auditors and allow others to rely on auditor's work. GAGAS provides a framework for conducting high quality government audits with competence, integrity and objectivity. GAGAS also contains requirements and guidance on ethics, independence, auditor's professional judgment, quality control and assurance, the performance of fieldwork and reporting. AUTHORITY: The internal audit activity, with strict accountability for confidentiality and safeguarding records and information, is authorized full, free, and unrestricted access to the County's records, documents, physical properties, and personnel that are necessary for purposes of conducting an audit or performing audit duties subject to the limitations of applicable law and established professional privilege. All employees are requested to assist the internal audit activity in fulfilling its roles and responsibilities. The internal audit activity will also have free and unrestricted access to those charged with governance. ORGANIZATION: qk The Internal Auditor will report functionally and administratively to the County Administrator. The Internal Auditor will be subject to all normal and ordinary management and oversight practices required to ensure the effective and efficient performance of duties and delivery of internal audit services. The Audit Committee will advise the Internal Auditor and the County Administrator on matters related to: • The internal audit charter, • The risk based internal audit plan, • The internal audit budget and resource plan. N The County Administrator and the Audit Committee will: Receive communications from the Internal Auditor on activity's and performance relative to the internal audit plan and other matters, Make inquiries of the Internal Auditor to determine if scope or resource limitations exist which impede the internal audit function. The Internal Auditor will communicate and interact directly with the County Administrator and the Audit Committee. INDEPENDENCE AND OBJECTIVITY: AA The internal audit activity will remain free from interference by any element in the County, including matters of audit selection, scope, procedures, frequency, timing, or report content to permit maintenance of a necessary independent and objective mental attitude. The Internal Auditor will have no direct operational responsibility or authority over any of the activities audited. Accordingly, the Internal Auditor will not implement internal controls, develop procedures, install systems, prepare records, or engage in any other activity that may impair the Internal Auditor's judgment. The Internal Auditor will exhibit the highest level of professional objectivity in gathering, evaluating, and communicating information about the activity or process being examined. The Internal Auditor will make a balanced assessment of all the relevant circumstances and not be unduly influenced by self-interest or by others in forming judgments. The Internal Auditor will confirm to the County Administrator and the Audit Committee, at least annually, the organizational independence of the internal audit activity. RESPONSIBILITY: The scope of internal auditing encompasses, but is not limited to, the examination and evaluation of the adequacy and effectiveness of the County's governance, risk management, and internal controls as well as the quality of performance in carrying out assigned responsibilities to achieve the County's stated goals and objectives. This includes: • Evaluate the reliability and integrity of information and the means used to identify, measure, classify, and report such information, • Evaluate the systems established to ensure compliance with policies, plans, procedures, laws, and regulations which could have a significant impact on the County, • Evaluate the means of safeguarding assets and, as appropriate, verify the existence of such assets, • Evaluate the effectiveness and efficiency with which resources are employed, • Monitor and evaluate governance processes, • Monitor and evaluate the effectiveness of the County's risk management processes, • Perform consulting and advisory services related to governance, risk management and internal control as appropriate for the County, • Report periodically on the internal audit activity's purpose, authority, responsibility, and performance relative to its plan, • Report significant risk exposures and control issues, including fraud risks, governance issues, and other matters requested by the County Administrator and/or the Audit Committee, • Evaluate specific operations at the request of the County Administrator. INTERNAL AUDIT PLAN: At least annually, the internal auditor will present to the County Administrator and Audit Committee an internal audit plan for review and approval. The internal audit plan will consist of a work schedule as well as budget and resource requirements for the next fiscal year. The internal auditor will communicate the impact of resource limitations and significant interim changes to the County Administrator and the Audit Committee. The internal audit plan will be developed based on a prioritization of the audit universe using a risk-based methodology, including input of the County Administrator and Audit Committee. The internal auditor will review and adjust the plan, as necessary, in response to changes in the County's risks, operations, programs, systems, and controls. Any significant deviation from the approved internal audit plan will be communicated to the County Administrator through periodic activity reports. REPORTING AND MONITORING: A written internal audit report will be prepared and issued by the Internal Auditor following the conclusion of each internal audit engagement and will be distributed as appropriate. The internal audit report may include management's response and corrective action taken or to be taken in regard to the specific findings and recommendations. Management's response, whether included within the original audit report or provided thereafter by management of the audited area should include a timetable for anticipated completion of action to be taken and an explanation for any corrective action that will not be implemented. The internal audit activity will be responsible for appropriate follow-up on engagement findings and recommendations. All significant findings will remain in an open issues file until cleared. The Internal Auditor will periodically report to the County Administrator and Audit Committee on the internal audit activity's purpose, authority, and responsibility, as well as performance relative to its plan. Reporting will also include significant risk exposures and control issues, including fraud risks, governance issues, and other matters needed or requested by the County Administrator. QUALITY ASSURANCE%6" "K The internal audit activity will ensure a thorough and well defined quality assurance process exists over deliverables produced by the Internal Auditor (including workpapers, reports and plans). Continuous improvement monitoring and assessments for the efficiency and effectiveness of the internal audit activity will also be conducted. The internal auditor will communicate to the County Administrator on the internal audit activity's quality assurance and continuous improvement processes, including results of ongoing internal assessments and external assessments conducted at least every three years. M Roanoke County, Virginia Internal Audit Charter Approved this day of January, 2016. Tanya Catron, Internal Auditor Thomas C. Gates, County Administrator Audit Committee Chairman ■ ACTION NO. ITEM NO. E-2 AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER MEETING DATE: January 26, 2016 AGENDA ITEM: Request to approve the Amended and Restated New River Valley Commerce Park Participation and Revenue Sharing Agreement SUBMITTED BY: APPROVED BY: Jill B. Loope Director of Economic Development Thomas C. Gates County Administrator COUNTY ADMINISTRATOR'S COMMENTS: SUMMARY OF INFORMATION: Roanoke County is one of eleven (11) member localities of the Virginia's First Regional Industrial Facility Authority (VFRIFA), created to facilitate regional economic development projects. As an original participant in the Authority, Roanoke County and each member locality entered into the New River Valley Commerce Park Participation agreement to acquire and develop the New River Commerce Park property. The agreement was amended on two (2) occasions; August 2001 to reflect membership adjustments, and December 2010 to expand the project description, amend the finance plan and revenue sharing provision, and voting approval required to lease or dispose of property. Currently, VFRIFA members are represented on both the Project Participation Committee and the Authority. This amendment dissolves the Committee and grants decision making authority to members of the VFRIFA. This will streamline and eliminate duplicative management and oversight while preserving the member decision making responsibilities. This amendment preserves all existing rights and responsibilities of Roanoke County as a member of the VFRIFA. This Amended and Restated Agreement establishes the following: An expanded project description detailing overall management and development requirements of the Commerce Park. Page 1 of 2 2. Dissolves the Commerce Park Participation Committee 3. Preserves the voting rights of the Participants as shareholders in the Commerce Park 4. Updates the Finance Plan for the Commerce Park 5. Amends the original share payments to include only the payment of debt service 6. Amends the Revenue Sharing Provisions to provide for 1% of taxes collected be retained to offset administrative costs, and provides forthe collection of replacement tax should the Machinery and Tools Tax ever be abolished. FISCAL IMPACT: None ALTERNATIVES: Deny approval of the Agreement STAFF RECOMMENDATION: Staff recommends approval of the Amended and Restated New River Valley Commerce Park Participation and Revenue Sharing Agreement. Page 2 of 2 V9111-'sFirst Virginia's First Regional Industrial Facility Authority 6580 Valley Center Drive, Suite 124 Radford, VA 24141 Phone (540) 639-1524 FAX (540) 831-6093 Amended and Restated Commerce Park Participation Agreement Significant Modifications from Past Agreements The enclosed Amended and Restated Commerce Park Participation Agreement is intended to update, streamline, and clarify how the NRV Commerce Park is being managed and developed, VFRIFA' role in the NRV Commerce Park, and responsibilities of member participants. The following are the significant modifications made to past agreements that this new Agreement is intended to replace: 1. Stand Alone Agreement: Acknowledges past agreements; however, it is intended to be a stand-alone document that does not require constant review of past agreements to verify provisions. This helps simplify research and understanding of how the NRV Commerce Park is to be managed and developed. 2. Project Description: Creates a more general project description for the NRV Commerce Park to include any item needed to develop the Park. This allows flexibility for Park development without altering the original intent for development of the Park. 3. NRV Commerce Park Property: Updates the NRV Commerce Park description to include the current boundaries, as well as leaving the ability to modify the boundaries of the Park without requiring a modification to the Agreement. This clarifies the current boundaries of the Park and allows flexibility for modifications in the future. 4. NRV Commerce Park Share Payments: Sets a deadline for receiving annual share payments of September 30th with a 45 day grace period before it is considered a material breach. Past agreements had a deadline of appropriation by July 15th and a 20 day grace period before it was considered a material breach. This allows member participants additional time and flexibility in making annual payments. 5. NRV Commerce Park Shares: Provides updates and clarification to ownership, when shares were issued, and for what purpose shares were issued. This helps to clarify ownership status and past actions regarding ownership. 6. Project Participation Committee: Dissolves the Project Participation Committee; however, the rights and investment of participants is preserved. This allows for a more streamlined approach to decision making, finances, legal decisions, and meetings 7. Clarified Shares: Clearly states how shares are issued and that there is no set number of shares for the NRV Commerce Park. This helps clarify the process for share issuance. 8. Original Share Payments: Modifies when the original debt that was used to purchase the land will cease to coincide with completion of bond repayment for the land purchase. Past agreements were left open-ended, so payments never ceased. This provides assurances to member participants that the shares are for the land only and once the land is paid for, the share payment cease. 9. Administrative Expenses: Moves all administrative expenses of managing and developing the NRV Commerce Park to VFRIFA. This streamlines billing and simplifies financial transactions. 10. Voting: Clarifies that each member participant shall vote their shares as a block. This will prevent any one participant from splitting their shares to vote different positions on one issue. 11. Use of Funds: Provides the Authority the ability to use any funds for any purpose, instead of specifying how funds must be used. This provides flexibility to the Authority and prevents conflicts for future funding allocations. 12. Finance Plan: Updates the finance plan to include Project Agreements, revenue, expenses, long-term debt, and other pertinent financial information. This provides for a quick reference of finances for VFRIFA and the NRV Commerce Park. 13. Revenue Sharing: Provides for 1% of all taxes collected to be retained by VFRIFA to offset administrative costs. Also, if the Machinery & Tool tax is abolished, the replacement tax shall be collected instead of requiring Pulaski County to pay the value of Machinery & Tool taxes to VFRIFA in perpetuity, even if the tax is abolished. This provides a source of income for administrative expenses (instead of using annual dues for shares) and clarifies what would happen if the Machinery and Tool tax is ever abolished. 14. Revenue Distribution: Clarifies that revenue from new industries shall be used to pay any costs incurred with locating the industry in the NRV Commerce Park, then allows for remaining revenue to be used in any manner in which the Authority designates. This provides assurances to member participants that new debt will be repaid with new revenue, while allowing flexibility in additional revenue expenditures. 15. Performance Agreement: Requires that all new industries locating in the NRV Commerce Park to execute a performance agreement with VFRIFA. This puts a process that is currently used in writing to ensure consistent use of Performance Agreements for placement of new industries. 16. Restrictive Covenants: Allows the restrictive covenants to be in effect, even if not recorded with the Pulaski County Clerk of Court. This provides flexibility to the NRV Commerce Park development, while protecting how the Park is developed. 17. Participant Withdrawal: Clarifies that the Code of VA shall be followed and approval from any applicable debt and bond holders shall be obtained. This aligns the Agreement with Code of Virginia regulations. 18. Records Retention: Requires that NRV Commerce Park records to be retained in the VFRIFA office, which shall be located in one of the member locality's jurisdiction. This clarifies the location of records, as well as the location of the VFRIFA office. 19. Exhibits: Includes exhibits to clarify the Commerce Park property, ownership of the Commerce Park, and the financing plan. This helps clarify these complex items that are critical to the understanding and implementation of this Agreement. AMENDED AND RESTATED NEW RIVER VALLEY COMMERCE PARK PARTICIPATION AND REVENUE SHARING AGREEMENT THIS AMENDED AND RESTATED PARTICIPATION AND REVENUE SHARING AGREEMENT ("Agreement") is dated this 9th day of December, 2015, between and among Virginia's First Regional Industrial Facility Authority and the Participants defined below. WITNESSETH: WHEREAS, the undersigned governing bodies are each member localities of Virginia's First Regional Industrial Facility Authority ("Authority") a body corporate, organized, and created pursuant to the Virginia Regional Industrial Facilities Act, Chapter 64 Title 15.2 of the Code of Virginia, 1950, as amended ("Act") and the Agreement Creating Virginia's First Regional Industrial Facility Authority dated September 1, 1998; and WHEREAS, pursuant to the authority granted under the Act to enter into agreements for the development of regional economic development projects the Authority and the County of Craig, Virginia, the County of Giles, Virginia, the County of Montgomery, Virginia, the County of Pulaski, Virginia, the County of Roanoke, Virginia, the County of Wythe, Virginia, the County of Bland, Virginia, the City of Radford, Virginia, the City of Roanoke, Virginia, the Town of Dublin, Virginia, the Town of Pearisburg, Virginia, and the Town of Pulaski, Virginia ("Original Participants") each entered into the New River Valley Commerce Park Project Participation Agreement — Initial Phase dated as of October 14, 1999 ("Participation Agreement") for the development of the Commerce Park Project; and WHEREAS, the Original Participants financed the acquisition of the Commerce Park Property and Initial Phase of the Commerce Park Project through the sale of shares which were financed by the Original Participants ("Financed Shares"); and {00119446.DOC } WHEREAS, on August 8, 2001, the Participation Agreement was amended whereby County of Wythe was allowed to sell its shares to the remaining participants and withdraw from the Participation Agreement leaving the County of Craig, Virginia, the County of Giles, Virginia, the County of Montgomery, Virginia, the County of Pulaski, Virginia, the County of Roanoke, Virginia, the County of Bland, Virginia, the City of Radford, Virginia, the County of Roanoke, Virginia, the Town of Dublin, Virginia, the Town of Pearisburg, Virginia, and the Town of Pulaski, Virginia as the remaining participants ("Participants"); and WHEREAS, on December 31, 2010, the Participation Agreement was amended a second time to expand the scope of the Project Description; amend the voting approval required to lease, use or otherwise dispose of real or personal property comprising the Commerce Park; amend the Finance Plan; and amend the revenue sharing provisions; and WHEREAS, pursuant to the Participation Agreement, the Commerce Park is undertaken in the name of the Authority, but the Project Participation Committee has the sole responsibility for decisions related to the construction, management, and overall implementation of the Commerce Park; and WHEREAS, the Participants are both members of the Project Participation Committee and members of the Authority; and WHEREAS, the Participation Agreement requires that the Authority approve the decisions of the Committee, which needlessly duplicates and complicates management and oversight of the Commerce Park; and WHEREAS, the Participants as members of the Participation Committee and as members of the Authority desire to dissolve the Committee and thereafter exercise their decision making responsibilities for the Commerce Park, as Participant shareholders and as members of the Authority; and {00119446.DOC } Page 2 of 12 WHEREAS, the Authority and Participants desire to amend and restate the Participation Agreement to (1) expand the scope of the Project Description to include the overall management and development of the Commerce Park; (2) dissolve the Project Participation Committee ("Committee"); (3) preserve the voting rights of the Participants as shareholders in the Commerce Park; (4) update the Finance Plan for the Commerce Park; (5) amend the original share payments to include only the payment of debt service; and (6) amend the Revenue Sharing provisions. NOW THEREFORE, the Authority and Participants acknowledge and agree that the original Commerce Park Project Participation Agreement and all subsequent Amendments thereto are hereby superseded by this Amended and Restated Participation Agreement as of the date of its adoption. L COMMERCE PARK DESCRIPTION AND PURPOSE The Project shall be known as the New River Valley Commerce Park ("Commerce Park"), which currently consists of approximately 973 acres located generally at VA -100 and Laboratory Drive (Route 790) in Dublin, Virginia (depicted on Exhibit A attached hereto)}, and shall include the management and development of the Commerce Park for the purpose of promoting economic and workforce development as authorized pursuant to the Virginia Regional Industrial Facilities Act, Chapter 64 of Title 15.2 of the Code of Virginia, 1950, as amended, and the Agreement Creating Virginia's First Regional Industrial Facility Authority. II. COMMERCE PARK UNDERTAKEN IN THE NAME OF THE AUTHORITY The Authority shall hold title to and have the power to lease, use, sell, encumber, transfer, and dispose of any real or personal property comprising the Commerce Park and may exercise all powers vested to the Authority pursuant to Virginia Code § 15.2-6405 with respect to the Commerce Park, upon approval of the Board of the Authority and Participants as set forth herein. Financing for the Commerce Park shall be arranged in the name of the Authority but all loan obligations for the ' The actual property making up the Commerce Park may change from time to time upon approval of the Authority and Participants as set forth herein. {00119446.DOC } Page 3 of 12 Commerce Park shall be the sole responsibility of those Participants who agree to take on debt through Project Agreements. III. NEW RIVER VALLEY COMMERCE PARK PARTICIPATION COMMITTEE The New River Valley Commerce Park Participation Committee is hereby dissolved. The Authority assumes responsibility for all of the decisions related to the operation and development of the Commerce Park, subject to approval of the Board of the Authority and the Participants' Representatives as set forth in Section V herein. IV. SHARES There is no set number of authorized shares for the Commerce Park. The Authority may issue shares upon approval of the Authority and Participants as set forth in Section V herein. There is only one class of shares, the purchase of which may be financed or paid in full upon issuance. Each Participant's ownership interest in the Park is determined by the total number of shares owned by the Participant as a percentage of the total number of shares issued. For the Financed Shares, the annual payment by Participants shall include only the amount necessary for the payment of the annual debt service that was incurred for the purchase of land for the Commerce Park (not including the Red Sun Farms grading debt), the financing costs, and all expenses related to the debt. Upon payment in full of the debt, the Participants' annual payments for the Financed Shares shall cease. Payments for the Financed Shares are due to the Authority annually on or before September 30th. Should any Participant fail or neglect to remit its share payment and such failure continues for more than forty-five (45) days following written demand by the Authority, such failure shall be considered a material breach of this Agreement and Participant shall forfeit all voting rights and rights to revenue sharing until all money due and owed by the Participant, including, but not limited to, reasonable attorneys' fees and collection costs incurred by the Authority, is paid in full. The {00119446.DOC } Page 4 of 12 Participant in default shall not be relieved of its portion of the Commerce Park debt and any request to withdraw from the Authority shall be subject to Section X of this Agreement. Participants may sell their shares to other Authority members subject to the approval of the terms of the sale by the Participants and the Authority, which approval shall not be unreasonably withheld. The Authority and each Participant acknowledges and agrees that it currently has an ownership interest in the Commerce Park as set forth in Exhibit B. V. VOTING Each Participant shall appoint one of its representatives on the Board of the Authority to vote its shares. Each share shall be entitled to one vote; however, Participants must vote all of their shares as a block. The Authority may not issue shares; incur debt; lease, sell, encumber, transfer, or dispose of any real or personal property comprising the Commerce Park; spend or distribute Revenue except as provided herein; or enter into any performance agreement or project agreement without an affirmative vote of both a majority of the shares entitled to vote and an affirmative vote of two-thirds of the Board Members of the Authority. In addition, no Participant may sell its shares without the approval of a majority of the shares and majority vote of the Board Members of the Authority. All other Commerce Park decisions may be made by a simple majority vote of the Board of the Authority. VI. COMMERCE PARK FINANCING PLAN The current Financing Plan for the Commerce Park is set forth in Exhibit C, which may be amended from time to time. In addition, upon approval of the Board of the Authority, the Authority may appropriate member dues from time to time to finance expenses related to the management, operation, and development of the Commerce Park. All financed debt obligations for the Commerce Park shall remain the responsibility of the Participants in the Commerce Park and not the Authority. With the exception of Authority dues, no Participant or Authority member shall be responsible for any monetary obligation or debt without its express consent. The Participants remain solely {00119446.DOC } Page 5 of 12 responsible for discharging the Authority's debt obligations in respect to the Commerce Park as set forth herein or in separate Project Agreements. VII. COMMERCE PARK BUDGET A proposed annual budget for the Commerce Park shall be developed by the Executive Director each year as part of the Authority's annual budget for each fiscal year beginning the following July 1. The budget shall include all contemplated expenditures for operations, capital expenses, project expenses, and debt service, and all anticipated revenues from taxes, grants, and other sources. This annual budget shall be presented to the Participants and Board Members of the Authority in time for amendment and adoption prior to July 1 of each year. VIII. REVENUE SHARING Pulaski County agrees to designate the following taxes received by Pulaski County from all business(es) and industy(ies) sited in the Commerce Park ("Business") as Revenue to be paid to the Authority and distributed as set forth herein. Machinery and Tools Tax: Ninety -Five Percent (95%) of the machinery and tools taxes collected by Pulaski County for each Business located in the Commerce Park, shall be paid to the Authority annually on or before December 31, in perpetuity, or until otherwise agreed to by the parties. Pulaski County shall retain Five Percent (5%) of the machinery and tools taxes collected. In the event that the Machinery and Tools Tax is abolished by the General Assembly and replaced with an alternate tax structure, the alternate tax revenue collected from each Business in the Commerce Park shall be paid by Pulaski County to the Authority. Should the Machinery and Tools Tax not be replaced with an alternate tax, the parties agree to consider and negotiate a substitute source of Revenue to replace the Machinery and Tools Tax. Business Personal Property and Real Estate Tax: Pulaski County agrees to remit to the Authority a percentage of the business personal property and real estate taxes ("Taxes") collected from each Business sited in the Commerce Park as Revenue for fifteen (15) years from the due date {00119446.DOC } Page 6 of 12 of each Business' first assessment. For years one (1) through nine (9), Pulaski County will pay the Authority One Hundred Percent (100%) of the Taxes collected for each Business. For years ten (10) through eleven (11), Pulaski County shall remit to the Authority Seventy-five Percent (75%) of the Taxes collected. For years twelve (12) through thirteen (13), Pulaski County shall remit to the Authority 50% of the Taxes collected. Finally, for years fourteen (14) through fifteen (15), Pulaski County shall remit Twenty-five Percent (25%) of the Taxes collected. If during the fifteen (15) years a Business leaves the Park and a new Business takes its place, the Taxes remitted shall be calculated on the new Business for the years remaining in the original fifteen (15) year period ( at minimum) according to the percentages noted above. However, the parties to this Agreement may negotiate an alternative arrangement as appropriate. Miscellaneous Revenue: Miscellaneous Revenue includes, but is not necessarily limited to, Commerce Park land leases, business rent, land sale proceeds, revenue received from share purchases, and the discretionary appropriation of Authority dues to the Commerce Park. In addition, the Authority may add a water use surcharge of up to $1.00 per 1,000 gallons of water used by any Business in the Park. Miscellaneous Revenue may be used by the Authority and Participants to benefit the Commerce Park as negotiated in Project Agreements, in other financing arrangements, or in any lawful manner as determined by the Authority and Participants. Distribution of Revenue: All Revenue received from Pulaski County shall be distributed by the Authority as follows: Prior to any distribution of Revenue, the Authority shall retain One Percent (1%) of all Revenue collected by Pulaski County and paid to the Authority as an administrative fee. Next, Revenue received by Pulaski County from each Business shall be used to pay off any debt incurred to facilitate the siting of that Business in the Park as memorialized in a Project Agreement or some other agreement (i.e. Red Sun Farms Grading Project Agreement). Any remaining Revenue may be {00119446.DOC } Page 7 of 12 distributed to Participants based upon each Participant's percentage of Commerce Park shares owned or used for any other lawful purpose as approved by the Participants and Authority pursuant to Section V herein. Revenue Payments Subject to Appropriation by Pulaski County: Notwithstanding the foregoing, Pulaski County's agreement to remit the Revenue described herein to the Authority is a moral obligation and not a legal debt of Pulaski County. The payment of the Revenue described herein to the Authority is subject to annual appropriation by the Pulaski County Board of Supervisors. IX. REQUIREMENTS FOR DEVELOPMENT OF THE COMMERCE PARK All businesses locating in the Commerce Park shall execute a Performance Agreement with the Authority subject to approval by the Authority and Participants as set forth in Section V. The Performance Agreement may contain such terms and conditions as the parties agree. Each business locating to the Commerce Park shall be responsible for meeting all applicable federal, state, and local laws and the Commerce Park Restrictive Covenants, as may be amended, whether or not recorded in the public records. X. WITHDRAWAL OF PARTICIPANT Participants in the Commerce Park may withdraw from the Authority only as set forth in Virginia Code § 15.2-6415 or as the remaining Participants and the Authority may unanimously agree. The conditions of withdrawal must also be accepted by all secured debt and bondholders or their representatives. XI. LIMITATION OF LIABILITY/ANNUAL APPROPRIATION The Participants are solely responsible for discharging the Authority's obligations for the Commerce Park. The Authority is not responsible for the financing and debts of the Commerce Park. The revenue sharing, payments, and contributions to the Authority as set forth herein are specifically authorized pursuant to Virginia Code §§ 15.2-6406 and 15.2-6407. In the event such code provisions are held invalid so that payments and contributions hereunder may be considered a debt of a local {00119446.DOC } Page 8 of 12 government pursuant to Article VII, Section 10 of the Virginia Constitution, such payments and contributions shall not be debt of such participating local government, but shall be subject to and dependent upon annual appropriations being made from time to time by its governing body. Each participating locality agrees that its chief administrative officer shall annually request, using his or her best efforts, to secure the governing body's approval of such annual appropriations necessary to make the payments and contributions required by this Agreement. No provision herein shall be construed as a pledge of the full faith and credit of a participating local government. XII. COMMERCE PARK RECORDS All records of the Commerce Park shall be maintained with the records of Virginia's First Regional Industrial Facility Authority in the designated administrative office within a participating member locality. XIII. AMENDMENT This Agreement may be amended from time to time as the parties may agree, provided all amendments shall be in writing and shall require the unanimous consent of all Participants and the consent of the Authority. XIV. SEVERABILITY If any provision of this Agreement is held invalid by any court of competent jurisdiction, such holding shall not invalidate the remaining provisions herein. XV. EXECUTION OF COUNTERPARTS This Agreement may be executed in any number of counterparts each of which shall be an original and together shall constitute but one and the same Agreement. IN WITNESS WHEREOF, the Governing Bodies identified, by authorized action, have caused this Agreement to be executed, and their respective seals to be affixed hereto and attested by their respective clerks or secretaries commencing this day of , 2016. {00119446.DOC } Page 9 of 12 VIRGINIA'S FIRST REGIONAL INDUSTRIAL FACILITY AUTHORITY Attest: Approved as to form: Secretary of the Attorney, VFRIFA Chairman, Authority Board Authority Board COUNTY OF BLAND, VIRGINIA Attest: Approved as to form: Clerk, Board of Supervisors County Attorney Chairman, Board of Supervisors COUNTY OF CRAIG, VIRGINIA Attest: Approved as to form: Clerk, Board of Supervisors County Attorney Chairman, Board of Supervisors TOWN OF DUBLIN, VIRGINIA Attest: Approved as to form: Clerk, Town Council Town Attorney Mayor COUNTY OF GILES, VIRGINIA Attest: Approved as to form: Clerk, Board of Supervisors County Attorney Chairman, Board of Supervisors {00119446.DOC } Page 10 of 12 COUNTY OF MONTGOMERY, VIRGINIA Attest: Approved as to form: Clerk, Board of Supervisors County Attorney Chairman, Board of Supervisors TOWN OF PEARISBURG, VIRGINIA Attest: Approved as to form: Clerk, Town Council Town Attorney Mayor COUNTY OF PULASKI, VIRGINIA Attest: Approved as to form: Clerk, Board of Supervisors County Attorney Chairman, Board of Supervisors TOWN OF PULASKI, VIRGINIA Attest: Approved as to form: Clerk, Town Council County Attorney Mayor CITY OF RADFORD, VIRGINIA Attest: Approved as to form: Clerk, City Council City Attorney Mayor {00119446.DOC } Page I I of 12 Attest: Clerk, City Council Attest: CITY OF ROANOKE, VIRGINIA Approved as to form: City Attorney Mayor COUNTY OF ROANOKE, VIRGINIA Approved as to form: Clerk, Board of Supervisors County Attorney {00119446.DOC } Page 12 of 12 Chairman, Board of Supervisors L � _ iH A LL -• a --t - _ p oa 04 L N 3 z a N O N LL 0 2�<' N r ti a M O gah ti M � � r O ti M O M LCA O M O O Q L a i9. 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V). vl� vl� V). vl� vl� vl� vl� '0 N OO O O O O O O O O O O O O O O O O O O O O O O U s o 0 0 0 0 0 0 0 0 0 0 Ln CD N O U O ci T U > Y Y 0E o v o m o o a a U 1= 1= 0 o 0 0 U u° u° o°n U W m y 2 a z 3 u u r r r O O 0 ti 0 0 r W m E W E W s 0 O a s O O Cn d s O Q) W E U C 'rZ cu 0 N m 0 fl. � •V R m c Y R L L co O a w d N d E V) I-- m U d d j E N O in w ti c � a s E 3 Q L o s U of a F, s r M 0 Ln 0 N M v� C1 m CL D Virginia First Regional Industrial Facility Authority 6580 Valley Center Drive, Suite 124 ginia's First Radford, VA 24141 Phone (540) 639-1524 FAX (540) 831-6093 New River Valley Commerce Park Financing Plan Summary The New River Valley (NRV) Commerce Park is owned by Virginia's First Regional Industrial Facility Authority (VFRIFA) and is intended to be developed for large-scale industrial companies that have a positive impact on regional job creation. In order to achieve the goal of creating an industrial park that contains multiple large companies, a range of financing and funding sources is needed. VFRIFA has the authority to take on long-term debt, enter into project agreements, and various other means of financing, as permitted by law. This document details the current financing plan in place for the development and management of the NRV Commerce Park. Project Agreements Currently, there are three separate Project Agreements in place, each of which has a financial impact to the development of the NRV Commerce Park, as follows: • Red Sun Farms Grading Project Agreement (2014)- Pulaski County agreed to purchase 10,000 CP shares at $40/ share ($400,000 total) to fund a portion of the grading that was needed to prepare the site for construction of Red Sun Farms. • Gas Line Extension Project Agreement (2014)- Pulaski County agreed to purchase 10,500 CP shares at $40/ share, with the option for the shares to be repurchased, ($420,000 total) to fund a 6" steel gas main extension to provide gas service to the NRV Commerce Park. • International Boulevard Right -of -Way Surveying Project Agreement (2014)- The Town of Pulaski agreed to purchase 100 CP shares at $40/ share ($4,000 total) to fund a right-of-way survey for International Boulevard. NRV Commerce Park Ownership Ownership in the NRV Commerce Park is based on the number of shares purchased or financed by the member localities. Currently, there are 11 shareholders in the NRV Commerce Park. For more information regarding shares and ownership, please see Exhibit B. Annual Budget and Dues VFRIFA adopts an annual budget that includes management and development of the NRV Commerce Park, as well as repayment of any outstanding debt. Annual dues for VFRIFA member localities are $5,000. These dues may be used to cover NRV Commerce Park expenses, if so appropriated by the VFRIFA Board of Directors. Revenue Revenue for the NRV Commerce Park comes from a variety of sources, including, but not limited to tax revenue, farm land leases, water surcharge, business rent, and land sale proceeds. Tax revenue is based on the companies located in the NRV Commerce Park, is collected by Pulaski County, and then shared with VFRIFA. Machinery and Tools tax is shared with VFRIFA in perpetuity. 5% of the Machinery and Tools tax revenue is retained by Pulaski County for incurred expenses, and 1% is retained by VFRIFA for administrative expenses. The remaining 94% is provided to the NRV Commerce Park as annual revenue. Real estate and business personal property taxes are shared for a 15 year period. 1% of the real estate and business personal property taxes is retained by VFRIFA for administrative expenses. Please see the Amended and Restated New River Valley Commerce Park Participation and Revenue Sharing Agreement for specific tax revenue and sharing details. Most of the property located in the NRV Commerce Park is currently being leased as farm land. While monetarily insignificant, these leases ensure the property is maintained and provide additional crop, hay, and grazing land for local farmers. Currently, leases are renewed on an annual basis. VFRIFA has the ability to add a surcharge of up to $1.00 per 1,000 gallons of water used by any business or industry in the NRV Commerce Park. The purpose of this surcharge is to help repay the debt to the Pulaski County Public Service Authority for the upgraded water and sewer lines in the Park. VFRIFA has the ability to charge rent for businesses locating in the NRV Commerce Park, whether as part of regular costs of doing business or as a penalty for not meeting certain investment or job thresholds. In addition, there are several outparcels that are unsuitable for industrial development which may be sold or developed for other purposes to generate revenue for VFRIFA. Expenses Expenses for the NRV Commerce Park are based on long-term debt repayment, property improvements, engineering/ studies, and miscellaneous overhead costs. While expenses vary year-to-year, the most significant expense is long-term debt repayment. More detailed information for long-term debt repayment can be found in the following section. The annual budget follows the VFRIFA fiscal year, which runs from July 1- June 30. Attachment 41 is the annual budget from fiscal year 2015. Long -Term Debt Original CP Shares were financed by member localities in order to pay annually for purchasing the property necessary to create the NRV Commerce Park. These annual payments cover the repayment costs for the long-term debt obligations. Please see Exhibit B for more information regarding the original share purchase. In order to consolidate past debt, release the lien on the property, and obtain a lower interest rate, VFRIFA entered into an agreement with the Pulaski County IDA for the issuance and repayment of bonds that were taken out by the Pulaski County IDA. A Taxable Series 2013 Bond was taken out by the Pulaski County IDA in the amount of $6,810,000. General Debt consisted of $5,210,000 and Red Sun Farms Grading Debt consisted of $1,600,000. Debt payments began in December 2013. General Debt will be retired in June 2039. Red Sun Farms Grading Debt will be retired in June 2028. Attachment 92 contains more in depth information on the IDA bonds and repayment schedule. Attachments • Fiscal Year 2015 Annual Budget • IDA Bond Information and Repayment Schedule m L a v L E Ln rl N LUL OLnO O �.0O rl 00000000 000 p OI-oI-o . 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ITEM NO. G- AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER MEETING DATE: January 26, 2016 AGENDA ITEM: Ordinance amending Section 2-115 "Rules of Debate" of the Roanoke County Code to provide for the requirement of a "Second" for all motions before debate at the Board of Supervisors Meetings SUBMITTED BY: Ruth Ellen Kuhnel County Attorney COUNTY ADMINISTRATOR'S COMMENTS: SUMMARY OF INFORMATION: The first reading of this ordinance was held on January 12, 2016. At that meeting, Supervisor McNamara amended the originally proposed ordinance to remove changes to Section 2-114 and add additional language to Section 2-115(h). Amend Section 2-115(1). The section sets forth that no second to motions shall be required in order for the Board to consider a motion. The proposed amendment would require another member second any motion before the motion can be considered by the Board in public debate. Amend Section 2-115(h). This amendment to the Code prohibits a Board member from remaking the same or any other motion at a t meeting, if the existing Board has acted on the same or similar motion in the last twelve (12) months. A strike through version of the amendment as proposed is attached. ALTERNATIVES: Do not change the Rules of Debate and no second will be required before discussion and vote on a motion in public debate. Page 1 of 2 STAFF RECOMMENDATION: The staff does not have a recommendation. The proposed ordinance amendment pertains to the operating procedures of the Board of Supervisors. Page 2 of 2 AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA, HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER ON TUESDAY, JAN URAY 12, 2016 ORDINANCE AMENDING SECTION 2-114 "AGENDA" AND SECTION 2-115 "RULES OF DEBATE" OF THE ROANOKE COUNTY CODE TO PROVIDE FOR THE REQUIREMENT OF A "SECOND" FOR ALL MOTIONS BEFORE DEBATE AT BOARD OF SUPERVISORS MEETINGS WHEREAS, the Board of Supervisors believes that it is in the public interest to clarify its Rules of Board Procedure to specify that a second is required for any motion raised in a session; and WHEREAS, the Rules of the County Board Procedures are located in the Roanoke County Code, Article V, Chapter 2; and WHEREAS, Robert's Rules of Order, Newly Revised, 11th Edition (RRO) provides guidance for the use of the seconding of a motion to ensure that only germane business is before the session; and WHEREAS, the first reading of the ordinance was held on January 12, 2016, and the second reading of the ordinance was held on January 26, 2016. that: NOW, THEREFORE, BE IT ORDAINED by the Board of Supervisors as follows 2, Real 96�+}ir�n "n" Will FeplaGe in its pe.ptiirety, feFmor oan+it9p Lon" to rizAP]. f7 ,�" � � ��� cracccTvrr�c�rc-crcr. "Th(QAgeRda GYmde a tIma Whan aRy beaFd mamher m y hriRg a Page 1 of 2 2. Within Section 2-115. Rules of Debate, Roanoke County Code, Article V, Chapter 2, new section "i" will replace, in its entirety, former section I" to read: "All motions shall require a second. After another member seconds the motion, the chairman shall state the question on the motion, and then the motion shall be open to debate. At the conclusion of the debate, the chairman shall put the question to the vote." 3. Within Section 2-115, Rules of Debate, Roanoke County Code, Article V, Chapter 2, new section "h" will replace, in its entirety, former section "h" to read: "Nothing herein shall be construed to prevent any member of the board from making or remaking the same or any other motion at a subsequent meeting of the board, provided the existing Board has not acted on the same or similar motion in the last twelve (12) months. 4. This ordinance shall take effect from and after January 26, 2016. Page 2 of 2 ACTION NO. ITEM NO. H.1-5 AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER MEETING DATE: AGENDA ITEM: SUBMITTED BY: APPROVED BY: January 26, 2016 Appointments to Committees, Commissions and Boards Deborah C. Jacks Chief Deputy Clerk to the Board Thomas C. Gates County Administrator COUNTY ADMINISTRATOR'S COMMENTS: SUMMARY OF INFORMATION: 1. Board of Zoning Appeals (appointed by District) The Windsor Hills Magisterial District representative has passed away. Mr. Karr's five (5) -year term expires June 30, 2016. 2. Budget and Fiscal Affairs Committee (BFAC) (appointed by District and At -Large) The Budget and Fiscal Affairs Committee shall be comprised of eleven (11) members with each Board Supervisor having an appointment, five members appointed jointly by the Board of Supervisors, and one ex officio appointment representing County Administration. Mr. Gates is currently working with the Board on recommendations to this committee. 3. Clean Valley Council (At Large) Adam Cohen has resigned his appointment to the Clean Valley Counsel. His three- year term expired June 30, 2015. Page 1 of 2 4. Economic Development Authority (EDA) (appointed by District) The following four-year terms will expire on September 26, 2015: a) Greg Apostolou, representing the Hollins Magisterial District is eligible for reappointment 5. Parks, Recreation and Tourism Advisory Commission (appointed by District) The following three-year term expired on June 30, 2015: a) Max Beyer, representing the Hollins Magisterial District; Mr. Beyer is eligible for reappointment. Page 2 of 2 AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA, HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER ON TUESDAY, JANUARY 26, 2016 RESOLUTION APPROVING AND CONCURRING IN CERTAIN ITEMS SET FORTH ON THE BOARD OF SUPERVISORS AGENDA FOR THIS DATE DESIGNATED AS ITEM I- CONSENT AGENDA BE IT RESOLVED by the Board of Supervisors of Roanoke County, Virginia, as follows: That the certain section of the agenda of the Board of Supervisors for January 26, 2016, designated as Item I - Consent Agenda be, and hereby is, approved and concurred in as to each item separately set forth in said section designated Items 1 through 4 inclusive, as follows: 1. Approval of minutes — October 27, 2015 2. Request to accept and allocate grant funds in the amount of $9,268 to the Clerk of the Circuit Court from the Commonwealth of Virginia for fiscal year 2015/2016 3. Donation of a Police Dog to the Roanoke County Police Department 4. Confirmation of appointments to Court -Community Corrections Alcohol Safety Action Program (ASAP) Policy Board; Court -Community Corrections Program — Regional Community Criminal Justice Board; Roanoke Valley -Alleghany Regional Commission (Regional Stormwater Management Committee), Roanoke Valley Transportation Planning Organization, Roanoke Valley - Alleghany Regional Commission, Social Services Board, Virginia Association of Counties, Virginia's First Regional Industrial Facility Authority and Western Virginia Regional Jail Authority Page 1 of 1 ACTION NO. ITEM NO. 1-2 AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER MEETING DATE: January 26, 2016 AGENDA ITEM: Request to accept and allocate funds in the amount of $9,268 to the Clerk of the Circuit Court from the Commonwealth of Virginia for fiscal year 2015/2016 SUBMITTED BY: Steven A. McGraw Clerk of Circuit Court APPROVED BY: Thomas C. Gates County Administrator COUNTY ADMINISTRATOR'S COMMENTS: SUMMARY OF INFORMATION: Technology Trust Funds, representing fees collected by the Roanoke County Circuit Court Clerk's Office, have been received from the State in the amount of $9,268. These funds have been earmarked for the purposes of maintenance and postage needs. These funds must be appropriated to the Clerk of Circuit Court. FISCAL IMPACT: None. All funds are provided by the Commonwealth. Ordinance #052615-3 appropriated various grants donations, and other miscellaneous revenues for various functions and purposes that are routine and usual in nature for the 2015-2016 fiscal year. Funds are to be accepted and allocated as follows 331000-5210: $91 and 102817-5850: $9,177. STAFF RECOMMENDATION: Staff recommends appropriating $9,268 to the Clerk of Circuit Court for the fiscal year 2015/2016. Page 1 of 1 ACTION NO. ITEM NO. 1-3 AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER MEETING DATE: January 26, 2016 AGENDA ITEM: Donation of a Police Dog to the Roanoke County Police Department SUBMITTED BY: Howard B. Hall Chief of Police APPROVED BY: Thomas C. Gates County Administrator COUNTY ADMINISTRATOR'S COMMENTS: SUMMARY OF INFORMATION Throw Away Dogs Project, a rescue organization that rehabilitates dogs for the purpose of converting rescued dogs to be used as Police K -9's, has offered to donate to the Roanoke County Police Department an eighteen month old Belgian Malinois K-9. The dog has been evaluated by a veterinarian and K-9 trainers and is deemed suitable for police work. It will be certified in tracking, narcotics detection and patrol work. If this donation is accepted, the dog will become part of the Police Department's K-9 Unit. A handler will be selected and trained with the dog and the team will be deployed for field work in the Uniform Division. Deployment of this K-9 team will permit the Police Department to replace a K-9 that was retired in 2015. The cost to purchase a similar dog would be approximately $6000-7000. FISCAL IMPACT: There is no fiscal impact. There are funds in the Police Department budget to support the operations of the K-9 teams and all necessary training requirements. ALTERNATIVES: 1. Accept the donation 2. Decline the donation Page 1 of 2 STAFF RECOMMENDATION: Staff recommends acceptance of this donation. Page 2 of 2 ACTION NO. ITEM NO. 1-4 AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER MEETING DATE: January 26, 2016 AGENDA ITEM: Confirmation of appointments to Court -Community Corrections Alcohol Safety Action Program (ASAP) Policy Board; Court - Community Corrections Program — Regional Community Criminal Justice Board; Roanoke Valley -Alleghany Regional Commission (Regional Stormwater Management Committee), Roanoke Valley Transportation Planning Organization, Roanoke Valley -Alleghany Regional Commission, Social Services Board, Virginia Association of Counties, Virginia's First Regional Industrial Facility Authority and Western Virginia Regional Jail Authority SUBMITTED BY: Deborah C. Jacks Chief Deputy Clerk to the Board APPROVED BY: Thomas C. Gates County Administrator COUNTY ADMINISTRATOR'S COMMENTS: SUMMARY OF INFORMATION: 1. Court -Community Corrections Alcohol Safety Action Program (ASAP) Policy Board The Board of Supervisors has recommended the appointment of J. Eric Orange, Sheriff to fill the remaining term left vacant by Sheriff Poff. This appointment will expire on June 30, 2017. 2. Court -Community Corrections Program —Regional Community Criminal Justice Board The Board of Supervisors has recommended the appointment of J. Eric Orange, Sheriff to fill the remaining term left vacant by Sheriff Poff. This appointment will expire on June 30, 2017. Page 1 of 3 3. Roanoke Valley -Alleghany Regional Commission (Regional Stormwater Management Committee) During closed session on January 12, 2016, it was the consensus of the Board to appoint George Assaid as the second elected representative for this commission. There is no term to this appointment. 4. Roanoke Transportation Planning Organization (formerly Roanoke Valley Area Metropolitan Planning Organization During closed session on January 12, 2016, it was the consensus of the Board to appoint P. Jason Peters as the elected representative from this commission. This appointment will expire June 30, 2017. It was also the consensus of the Board to appoint George Assaid as the second elected representative for this commission. This appointment will expire on June 30, 2017. 5. Roanoke Valley -Alleghany Regional Commission During closed session on January 12, 2016, it was the consensus of the Board to appoint George Assaid to fill the vacancy on this commission. This appointment will expire on June 30, 2016. 6. Social Services Advisory Board During closed session on January 12, 2016, it was the consensus of the Board to appoint Martha Hooker to fill the vacancy on this Board. This appointment will expire on July 31, 2018. 7. Virginia Association of Counties During the closed session on January 12, 2016, it was the consensus of the Board to appoint P. Jason Peters as the Liaison Board member. There is no term to this appointment. 8. Virginia's First Regional Industrial Facility Authority During the closed session on January 12, 2016, it was the consensus of the Board to appoint P. Jason Peters as the County's member on this Authority and Martha B. Hooker as alternate. The term of both of these appointments will expire on June 30, 2018. Page 2 of 3 9. Western Virginia Regional Jail Authority During the closed session on January 12, 2016, it was the consensus of the Board to appoint Joseph P. McNamara as the elected representative to this Authority and Martha B. Hooker as the alternate elected official. These appointments will expire December 31, 2016. Page 3 of 3 GENERAL FUND UNAPPROPRIATED BALANCE COUNTY OF ROANOKE, VIRGINIA Amount Audited balance at June 30, 2015 $ 21,799,195 Appropriated from 2015-2016 budget 506,153 % of General Fund Revenue 11.00% * Balance at January 26, 2016 $ 22,305,348 11.01 % ** Note: On December 21, 2004, the Board of Supervisors adopted a policy to increase the General Fund Unappropriated Balance incrementally over several years. * 2014-15 - Goal of 11 % of General Fund Revenues 2014-15 General Fund Revenues $198,174,499 11 % of General Fund Revenues $21,799,195 ** 2015-16 - Goal of 11 % of General Fund Revenues 2015-16 General Fund Revenues $202,656,326 11% of General Fund Revenues $22,292,196 The Unappropriated Fund Balance of the County is currently maintained at the goal of 11.00%. Submitted By Rebecca E. Owens Director of Finance Approved By Thomas C. Gates County Administrator IWr COUNTY OF ROANOKE, VIRGINIA CAPITAL RESERVES Minor County Capital Reserve (Projects not in the CIP, architectural/engineering services, and other one-time expenditures.) Amount Audited balance at June 30, 2015 $ 1,586,627 Appropriated for 2015-16 Capital budget (907,344) July 28, 2015 Appropriation to purchase voting machines and equipment (384,000) November 10, 2015 Allocation from expenditures for year end close out June 30, 2015 649,431 Balance at January 26, 2016 $ 944,714 Maior Countv Caaital Reserve (Projects in the CIP, debt payments to expedite projects identified in CIP, and land purchase opportunities.) Audited balance at June 30, 2015 $ 2,614,612 Appropriated for 2015-16 Capital budget (1,583,412) November 10, 2015 Allocation from revenues for year end close out June 30, 2015 $1,631,084 Balance at January 26, 2016 $ 2,662,284 Technoloav Caaital Reserve (Projects identified and prioritized by the Technology Governance Committee and approved by the County Administrator.) Audited balance at June 30, 2015 $ 314,058 Allocation to Computer Replacement Account (100,000) Balance at January 26, 2016 $ 214,058 Submitted By Rebecca E. Owens Director of Finance Approved By Thomas C. Gates County Administrator M, RESERVE FOR BOARD CONTINGENCY COUNTY OF ROANOKE, VIRGINIA Amount From 2015-2016 Original Budget $ 50,000 November 10, 2015 Appropriated funds to initiate the Intervenor process and develop strategy (15,000) Submitted By Approved By Balance at January 26, 2016 $ 35,000 Rebecca E. Owens Director of Finance Thomas C. Gates County Administrator r� COUNTY OF ROANOKE, VIRGINIA CHANGES IN OUTSTANDING DEBT Changes in outstanding debt for the fiscal year to date were as follows Submitted By Rebecca E. Owens Director of Finance Approved By Thomas C. Gates County Administrator Outstanding Outstanding June 30, 2015 Additions Deletions January 26, 2016 General Obligation Bonds $ 5,332,236 $ - $ - $ 5,332,236 VPSA School Bonds 104,311,123 7,761,248 96,549,875 State Literary Loans 1,825,775 - 1,825,775 - Lease Revenue Bonds 76,949,408 - 955,424 75,993,984 Capital Lease obligation 741,516 - 741,516 - $ 189,160, 058 $ - $ 11, 283, 963 - $ 177, 876, 095 Submitted By Rebecca E. Owens Director of Finance Approved By Thomas C. Gates County Administrator ACTION NO. ITEM NO. K-5 AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER MEETING DATE: AGENDA ITEM: SUBMITTED BY: APPROVED BY: January 26, 2016 Accounts Paid -December 2015 Rebecca E. Owens Director of Finance Thomas C. Gates County Administrator COUNTY ADMINISTRATOR'S COMMENTS: SUMMARY OF INFORMATION: Payments to Vendors Payroll 12/04/15 Payroll 12/18/15 Payroll 12/31/15 Manual Checks Grand Total Direct Deposit 1,182,479.21 1,343,044.67 1,345,619.97 Checks 67,748.95 54,254.09 66,599.31 7,166.70 Total $ 9,585,685.76 1,250,228.16 1,397,298.76 1,412,219.28 7,166.70 $ 13,652,598.66 A detailed listing of the payments to vendors is on file with the Clerk to the Board of Supervisors. _ d O C �L O O 'J W O N L C d R O � d W r LO r 1 Y v a O O 0 Nw 4)O � N C o � a R V R m N N 7 � C y N } L L V M fC Q N �� f0 � y N � ami Y a1 'a O LU cc CO -a O 4- c w O y o c a N E O R U W o N d � t (O O L L � U- E E O O C U CL N d 7 C d Of 7 m v 0 (00n ((o It m CMi m 1- m m o (0 m r- o o 0 v M - 1- aro 0 m O N V O m - - CO 00 V m N ooO M U r O O N N U7 CO O M 00 O O M V 00 O O N LO r N r O O 0 V O r M O M O M O O O O O LO 1 --LO O O LO Ch O O O LO O O V N 00 V O 0 0 00 00 V MJ LO m V 00 O O N O O (h 1� O C6 W O W U7 U7 V LO _ Ch a (h (h (h Ch N r O Cl) O Q O O LO O O c LL N L � d _ � O � d W r LO r v 0 (00n ((o It m CMi m 1- m m o (0 m r- o o 0 v M - 1- aro 0 m O N V O m - - CO 00 V m N ooO M U r O O N N U7 CO O M 00 O O M V 00 O O N LO r N r O O 0 V O r M O M O M O O O O O LO 1 --LO O O LO Ch O O O LO O O V N 00 V O 0 0 00 00 V MJ LO m V 00 O O N O O (h 1� O C6 W O W U7 U7 V LO _ Ch a (h (h (h Ch N r O Cl) O Q O O LO O O O LO O O r O M O O M W r LO r O O 1- O O 0 r N V a O V O 00 O LO U7 7 O r Ch pp O O O 7 N O O N O 000 O 0 M O 00 V O LO O M O M N r 00 00 0 O r O V O m l!7 M (1) V (h O O O V N V V V M N aD V r U m O m 0 O O M O O r O 0 0 N V r N O O CO N r 75 V O V LO V M 00 N 0 r O O r N O O m O LO N O O 00 r- 1- O M 1- r O LO V O O O O N O O O (h O O V O r U7 O W U7 V a O (h 00 N L _ 00 I� I- M O 00 O ( r N (D O C) O C) r O V r O CT O O O LO m 00 0 O N 00 1- 00 00 00 O V w N O r m M - LO - r-- 0) C) O m ? 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ITEM NUMBER K-8 AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER. MEETING DATE: January 26, 2016 AGENDA ITEMS: Statement of the Treasurer's Accountability per Investment and Portfolio Policy, as of 31 -Dec -15 SUMMARY OF INFORMATION: CASH INVESTMENT: SUNTRUST CON 21,075,454.12 21,075,454.12 GOVERNMENT: SCOTT STRINGFELLOW CONTRA (228,988.00) SCOTT STRINGFELLOW 56,010,000.69 WELLS FARGO 17,000,000.00 WELLS FARGO CONTRA (75,800.00) 72,705,212.69 LOCAL GOVT INVESTMENT POOL: 2,512,778.10 GENERAL OPERATION 10,183,796.84 10,183,796.84 MONEY MARKET: BRANCH BANKING & TRUST 1,082,003.68 SCOTT STRINGFELLOW - JAIL 1,103,271.41 SCOTT STRINGFELLOW 2,172,986.98 UNION FIRST 3,076,015.80 VALLEY BANK 2,512,778.10 WELLS FARGO 2,584,570.00 12,531,625.97 TOTAL 116,496,089.62 01/26/2016 ACTION NO. ITEM NO. M-1 AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER MEETING DATE: January 26, 2016 AGENDA ITEM: Work session to discuss an Amendment to the Erosion and Sediment Control Ordinance, Stormwater Management Ordinance and Design Manual and proposed Memorandum of Understanding with the Town of Vinton SUBMITTED BY: Arnold Covey Director of Community Development APPROVED BY: Thomas C. Gates County Administrator COUNTY ADMINISTRATOR'S COMMENTS: SUMMARY OF INFORMATION: In order to stay in compliance with Virginia Department of Environmental Quality (VDEQ) requirements, Roanoke County must amend two Ordinances: Chapter 8.1, Erosion and Sediment Control (ESC); and Chapter 23, Stormwater Management (SWM). Sub -section 23-1.8 of the SWM Ordinance also refers to the SWM Design Manual, which also requires amendment. These staff proposed amendments have been reviewed and supported by VDEQ. Additionally, during the Board's regular session on September 22, 2015, representatives from the Roanoke Regional Home Builder Association (RRHBA) presented information to the Board. Staff has met with the RRHBA and has resolved all outstanding issues. Staff will present the proposed amendments to the Board during this work session. In addition, the staff will present a proposal from Town of Vinton to administer the town's Stormwater Management/Virginia Stormwater Management Program (SWM/VSMP) process. A markup copy of the ESC Ordinance, SMW Ordinance and Design Manual is attached for your review. A summary sheet noting proposed changes is also attached for each. Page 1 of 1 ■ n s 5� n V •a Q L L O .a = _ O _ E C ♦ ♦ va) _ ■_ D w O m m O ■ r0 ?r E Eo .22 0. O C 0 L }+ 0. W N L i � A 3 0 0 0 (D s F o O U l,^ ) co U •- --j 0 Q a o '`) > 0 0 � L U) U U L E :3Nl, N 70 T OU) a -j IF U) a C: U N U �� 00 0 o .� L.Q 'E O .co ui C) Lu 2 O 2-, V I o i � N O j — T �� •_ j U O O co U CIO M � ,C C 4 2 O o o 0 - 7E)- O '� U) O t coO o 070 o E VV) M a T ,• o 0-U)U)E a� �C:O � N U � NI O — l,� C N CJ X O E N W 0- U) V 0 O Ir - 0 l0 T O O m O O N Q 'U 4- 0 aD N U 0 Ca a -j O El c�4-0 � U N _O E 4-0 U � O O U) 0 0 �4-0� E o O }' 0- O 0 a) ry >10 N N � � L 42O O � � U c�4-0 � U N _O E 4-0 F F LN U L O O U � U U L O � •� O 0 cn N E E cn O � L N ^L E E4-0 W L 0 " co L U �O C6 O O Q Q O :0: � (� cnC6 N C6 � o U � N N W-0 O " Do - O0 o C: Q O E U � '�r ^� L O� E � U � I Ca Q L Q Ca E ca E O lca T O E U) L cCL t A E O 7D a) 0 0 E E 0 A (D s o �, o cn > ca E E U � O O U).§ N • m a -j ._ C: U) N O O 'tn . � O L a -j � 4 .. �, }, o c� m U) •� • � p Ca • U � }' N 'cn .O U) 70 U L -L cn cn N O ._ oU E ca o .� _ �_ �_ '�Ca L L rx E-�r ♦"r y0 L 0 y0 Q C) am LU FMU) FM X LU Z a� CL 0 m 0 0 E U O O }p Q }' p 0 O O W4-0 O ♦"� L O � .� (� _0 cn L 01— CM U) 4-0 UJ �� � cn o 4-0 � �ozS oma. >-.E > O> �� N NU) W mow) �> �UC� I ca ca }, 72 U) Ca � E .E ♦n Ca rl Ca Ca i L.L C6 U- O U- V J U- C6 a� CL 0 m 0 0 E U a 7 -1 L- A C) Summary of proposed changes to Erosion and Sediment Control Ordinance BACKGROUND: In 2014, the General Assembly made changes to the VA Erosion and Sediment Control Law. Roanoke County's Erosion and Sediment Control Ordinance must be revised to reflect the current state requirements. While the revisions necessary to comply with state requirements are being made, the County is also making changes to better align with the VA model erosion and sediment control ordinance. These changes do not actually change any of the requirements, they just make it easier to correlate the County's Ordinance requirements with state requirements. The County regulates land disturbing activities that disturb 2,500 square feet or more, which is a lower disturbed area threshold than is required by the state. The state minimum disturbed area threshold is 10,000 square feet. The County had previously determined that this lower threshold is desired due to local conditions. The current VA Erosion and Sediment Control Law has some provisions (chiefly related to permanent stormwater management) that the development community and County staff believed were too stringent for small projects. County staff worked with DEQ staff to determine that the County, as the local authority, has a lot of discretion in regulating land disturbing activities below the state minimum area threshold of 10,000 square feet. Therefore, this proposed ordinance provides relieve from some of the state's erosion and sediment control technical requirements, relating to stormwater management, for projects that disturb less than the state's minimum disturbed area threshold of 10,000 square feet. SUMMARY OF PROPOSED SIGNIFICANT ORDINANCE CHANGES 1. Many minor adjustments to the ordinance that do not change the requirements. 2. In the preamble, stated that Roanoke County has responsibilities under its MS4 permit to address a sediment wasteload allocation. 3. Section 8.1-3 — Definition for Agreement in lieu of a plan has been expanded to allow their use for all land -disturbing activities that disturb 9,999 square feet or less; in addition to just land disturbing activities that are associated with the construction of a single- family residence. 4. Section 8.1-5 (b) and (c) — Required by state law. Requires projects that are subject to the erosion and sediment control requirements to address, and in some cases to provide, stormwater management for quantity control in accordance with the Virginia Stormwater Management Program (VSMP) regulations, even if the project is not subject to the VSMP regulations. 5. Section 8.1-6 (b) — expands the possible use of agreement in lieu of a plan for the construction of a single family residence. Present ordinance requires an erosion and sediment control plan for land disturbance of 10,000 sf or more. Proposed ordinance has no disturbance limit for possible use of agreement in lieu of plan for construction of a single family residence. Proposed ordinance: • The County may require additional information, or may decline to use an agreement in lieu of plan (require an erosion and sediment control plan), if in the County's opinion it is necessary to protect downstream property owners or the environment. 6. Section 8.1-6 (e) — Required by state regulation. Clarifies that all disturbance (even less than threshold) in a residential development must comply with regulations. 7. Section 8.1-6(I) — Clarifies how the County may address Erosion Impact Areas. 8. Section 8.1-7 — This is a new section that has special provisions for land -disturbing activities that disturb less than 10,000 square feet. This ordinance proposes to exempt these smaller land disturbing activities from some of the state technical requirements. • Applies to all land -disturbing activities that disturb less than 10,000 square feet, except for those land -disturbing activities that are in residential developments (cannot include these activities in residential developments due to state regulations). • Do not need to analyze or verify capacity of downstream channels and pipes. • No stormwater management measures to address any flow rate capacity or velocity requirements for downstream natural or man-made channels shall be required. • An agreement in lieu of plan may be used for all land disturbing activities (not just single family residence). 9. Section 8.1-8 — Requirement for surety contingency has been revised from 25% to 10%. 10. Section 8.1-11 —Appeals and Judicial Review has been rewritten as Hearings and Appeals. The requirements have been changed to match those contained in the SWM Ordinance. County Hearings will be heard by the County Administrator, rather than the Board of Supervisors. AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA, HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER ON TUESDAY, 1°4'zFebruary 9, 2016 ORDINANCE AMENDING CHAPTER 8.1. — EROSION AND SEDIMENT CONTROL OF THE ROANOKE COUNTY CODE WHEREAS, Chapter 8.1. — Erosion and Sediment Control of the Roanoke County Code was last amended by Ordinance #052708-19 on May 27, 2008; and WHEREAS, the General Assembly for the Commonwealth of Virginia has adopted legislative changes to the enabling legislation, Article 2.4, Chapter 3.1 of Title 62.1 of the Code of Virginia, and these changes must be incorporated into the ordinances of its local governments; and WHEREAS, the administration of the Erosion and Sediment Control Program was transferred to the Department of Environmental Quality (DEQ) by Acts 2013, Chapters 756 and 793; and WHEREAS, DEQ has adopted regulations to administer the Erosion and Sediment Control Program; and WHEREAS. DEQ has identified various Countv streams as beina impaired due to excessive sediment, has assicined Roanoke County a waste load allocation for sediment based on regional Total Maximum Daily Load studies, and requires Roanoke County in its Municipal Separate Storm Sewer System permit to provide additional stormwater controls; and Pagel of 26 WHEREAS, it is necessary for Roanoke County to amend Chapter 8.1 of the Roanoke County Code to incorporate the recent legislative and regulatory changes adopted by the Commonwealth of Virginia; and WHEREAS, these amendments revise various definitions and require compliance with water quantity of the Virginia Stormwater Management Program; and WHEREAS, the first reading of this ordinance was held on 4=February 9, 2016, and the second reading and public hearing was held on -2-&February 23 2016• - - I Dates must be verified NOW, THEREFORE, BE IT ORDAINED by the Board of Supervisors of Roanoke County, Virginia, as follows: That Chapter 8.1. — Erosion and Sediment Control be amended to read and provide as follows: Chapter 8.1 - EROSION AND SEDIMENT CONTROL Sec. 8.1-1. - Title, purpose and authority. This chapter shall be known as the "Erosion and Sediment Control and Steep Slope Development Ordinance of the County of Roanoke, Virginia." The purpose of this chapter is to prevent degradation of properties, stream channels, waters and other natural resources of Roanoke County Gen&epL^ +"o '� .,f the ^„,,.,+„ by establishing requirements for the control of soil erosion, sediment deposition and non-agricultural runoff and- ^o,+;^ ,rota+'^., and by establishing requirements for development of steep slopes, and by establishing procedures whereby these requirements shall be administered and enforced. This chapter is authorized by the Code of Virginia, Title 62.141, Chapter 3_15, Article 2.4 (Seen. 1 ^�0et 6eq-}, known as the Virginia Erosion and Sediment Control Law. Sec. 8.1-2. - Applicability of chapter in Town of Vinton. Page 2 of 26 The provisions of this chapter shall be applicable within the corporate limits of the Town of Vinton. Administrative procedures and review fees may be established to accommodate the review of plans for development located within the town. Sec. 8.1-3. - Definitions. As used in this chapter, unless the context requires a different meaning: Agreement in lieu of a plan means a contract between the plan -approving authority and the owner thatw*,.4 specifies conservation measures that must be implemented in the construction of a single-family residence uetwee�l�wv-zrrvavu��a�rve k6l;rcrred 2,5feet a , squaFa—feet and -IIA -Ir fi ge WURGlre�fi#y (250) to five h6I, dFed (500) 614.0.. yaFds; this contract may be executed by the plan -approving authority in lieu of a formal site plan. Agreement in lieu of a plan also means a contract between the plan -approving authority and the owner that specifies conservation measures that must be implemented in the construction of any land disturbing activity, other than a single-family residence, that disturbs between two thousand five hundred (2,500) square feet and nine thousand nine hundred and ninety nine (9,999) square feet; this contract may be executed by the plan - approving authority in lieu of a formal site plan. Applicant means any person submitting an erosion and sediment control plan for approval or requesting the issuance of a permit, when required, authorizing land - disturbing activities to commence. Board means the sta+o ;� -.Ad- _+or atie , h..ar,IVirginia State Water Control Board. Certified inspector means an employee or agent of a VESCPpFegFa+q authority who holds a certificate of competence from the B -board in the area of project inspection or (ii) is enrolled in the Board's training program for project inspection and successfully completes such program within one year after enrollment... Certified plan reviewer means an employee or agent of a VESCPq sGra+n authority who-._ {)Holds a certificate of competence from the B -board in the area of plan review; (2)—(ii) is enrolled in the Board's training program for plan review and successfully completes such program within one year after enrollment, or (iii) ids licensed as a professional engineer, architect, certified landscape architect or land surveyor pursuant to Aarticle 1 ( , Sec. 54.1-400 et seq.) of Cehapter 4 of Ttitle 54.1 or a professional soil scientist as defined in Sec. 54.1-2200 of the Code of Virginia. Page 3 of 26 Certified program administrator means an employee or agent of a VESCPpFegFam authority who holds a certificate of competence from the B14oard in the area of program administration or (ii) is enrolled in the Board's training program for program administration and successfully completes such program within one year after enrollment. Clearing means any activity which removes the vegetative ground cover including, but not limited to, root mat removal or top soil removal. �esi^i A-RtFih +iRg t.,oe�-� A+iM _. +r+r@A_tPA@.A+, The Plan Shall AAtA A all PA County means the County of Roanoke. QP_Q. d_P-d- w, a. +o. -w, o pp! med to la Rd +hat how hoo., ph YSi^olly dis+-HPh- ed ;-;Ad-. R Department means the D4epartment of Environmental Quality �+I Win. Development means a tract or parcel of land developed or to be developed as a single unit under single ownership or unified control which is to be used for any business or industrial purpose or is to contain three (3) or more residential dwelling units. Director means the D4irector of ^ .,i+„ d@'V@lr,.,. @Rt hio aGGigR the Department of Environmental Quality. District or Ssoil and W -water Ceonservation Ddistrict refers to the Blue Ridge Soil and Water Conservation District. Erosion and Ssediment Ceontrol P91an or P,nlan means a document containing material for the conservation of soil and water resources of a unit or group of units of land. It may include appropriate maps, an appropriate soil and water plan inventory, and management information with needed interpretations and a record of decisions contributing to conservation treatment. The plan shall contain all major conservation decisions and all information deemed necessary by the County to assure that the entire unit or units of land will be so treated to achieve the conservation obiectives. An Erosion and Sediment Control Plan must be prepared by a Virginia Professional Engineer, Land Surveyor, Landscape Architect, Architect, or Professional Soil Scientist. Page 4 of 26 Erosion impact area means an area of land not associated with current land disturbing activity but subject to persistent soil erosion resulting in the delivery of sediment onto neighboring properties or into state waters. This definition shall not apply to any lot or parcel of land of ten thousand (10,000) square feet or less used for residential purposes. Excavating means any digging, scooping or other methods of removing earth materials. Filling means any depositing or stockpiling of earth materials. Geotechnical report means a report provided at the applicant's expense, prepared and stamped by a professional engineer, that communicates site conditions, and recommends design and construction methods. (1) The geotechnical report shall include any or all of the following basic information, as determined by the professional engineer: a. Summary of all subsurface exploration data, including subsurface soil profile, exploration logs, laboratory or in situ test results, and ground water information; b. Interpretation and analysis of the subsurface data; c. Specific engineering recommendations for design; d. Discussion of conditions for solution of anticipated problems; and e. Recommended geotechnical special provisions. (2) For guidance in investigating site conditions and preparing geotechnical reports, the professional engineer may refer to all applicable sections of: "Checklist and Guidelines for Review of Geotechnical Reports and Preliminary Plans and Specifications", US Department of Transportation, Federal Highway Administration Publication No. FHWA ED -88-053, as amended. (3) The geotechnical report shall be submitted to the plan -approving authority and included in site development files prior to issuance of a land disturbing permit. Grading means any excavating or filling of earth material or any combination thereof, including the land in its excavated or filled conditions. Land -disturbing activity means any man-made land change to the land surface that whiAh may result in soil erosion from water or wind and the movement of sediments into state waters or onto lands in the Ceommonwealth, including, but not limited to, clearing, grading, excavating, transporting and filling of land, except that the term shall not include: (1) Minor land -disturbing activities such as home gardens and individual home landscaping, repairs and maintenance work; (2) Individual service connections; Page 5 of 26 (3) Installation, maintenance, or repairs of any underground public utility lines when such activity occurs on an existing hard-surfaced road, street or sidewalk provided such land-disturbing activity is confined to the area of the road, street or sidewalk thatw4G4 is hard-surfaced; (4) Septic tank lines or drainage fields unless included in an overall plan for land- disturbing activity relating to construction of the building to be served by the septic tank system; (5) Permitted surface or deep mining operations and projects, or oil and gas operations and projects conducted pursuant to Title 45.1 of the Code of Virginia; ( ) pleFati9R .,r dFi111R r fee ^ � . �h^ Well ite ds feed Iin^o % rrc=vr vrca, , ��virac�cca er�rrrcr, -and A_ff-site disposal areas; {7}Tilling, planting, or harvesting of agricultural, horticultural, or forest crops, or livestock feedlot operations; including engineering operations as follows: construction of terraces, terrace outlets, check dams, desilting basins, dikes, ponds, ditches, strip cropping, lister furrowing, contour cultivating, contour furrowing, land drainage, and land irrigation; however, this exception shall not apply to harvesting of forest crops unless the area on which harvesting occurs is reforested artificially or naturally in accordance with the provisions of Cshapter 11 ( Sec. 10.1-1100 et seq.) of Tthistitle 10.1 of the Code of Virginia or is converted to bona fide agricultural or improved pasture use as described in Ssubsection B of Sec. 10.1-1163; (7&)Repair or rebuilding of the tracks, rights-of-way, bridges, communication facilities and other related structures and facilities of a railroad company; (8-9)Agricultural engineering operations including but not limited to the construction of terraces, terrace outlets, check dams, desilting basins, dikes, ponds not required to comply with the Dam Safety Act,aFt!Glez (Va. Code § 10.1-604 et seq.) of Ghapte� 2-�eCed^ ^f V'Fg3R'a, ditches, strip cropping, lister furrowing, contour cultivating, contour furrowing, land drainage, and land irrigation; 1948) Disturbed land areas forallof less than two thousand five hundred (2,500) square feet less than +,.,^ hundred fifh (250) ,.,,hi.. yards in size; except as herein described for residential development in Section 8.1-6(e). (104-) Installation of fence and sign posts or telephone and electric poles and other kinds of posts or poles; (11-2) Emergency work to protect life, limb or property, and emergency repairs; howeverpfev4@4,—##at if the land- disturbing activity would have required an approved erosion and sediment control plan, if the activity were not an emergency, then the land area disturbed shall be shaped and stabilized in Page 6 of 26 accordance with the requirements of th8 Plan appFe„inr authepi4ythis Ord In AnrP Land_ disturbing Ppermit or approval means a permit or other form of approval issued by the Ceounty for the clearing, filling, excavating, grading, transporting of land or for any combination thereof or for any other land disturbing activitve set forth herein. e4en nfernew,en+ and e al a+ien Natural channel design concepts means the utilization of engineering analysis and fluvial geomorphic processes to create, rehabilitate, restore, or stabilize an open conveyance system for the purpose of creating or recreating a stream that conveys its bankfull storm event within its banks and allows larger flows to access its bankfull bench and its floodplain. Owner means the owner or owners of the freehold of the premises or lesser estate therein, a mortgagee or vendee in possession, assignee of rents, receiver, executor, trustee, lessee or other person, firm or corporation in control of a property. Peak flow rate means the maximum instantaneous flow from a given storm condition at a particular location. Permittee means the person to whom the peFmit a„+heriZinr land -disturbing approvalas is issued or the person who certifies that the approved erosion and sediment control plan will be followed. Person means any individual, partnership, firm, association, joint venture, public or private corporation, trust, estate, commission, board, public or private institution, utility, cooperative, county, city, town or other political subdivision of the commonwealth, any interstate body, or any other legal entity. Glist6IrbiRg an+iVi+ies a nit a nits of I.ARds and fer apffeviRg plans r +e G-Rdi+iens that May b@ able @XP@Gt@d tr;;At Af ';;Ad Dre 4eyelenw4ePt refers +e n ndi+iens at the time the eresien And sediment nen+rel +he tome the PPAGOGA and serlin-,en+ nen+rel PlaR fer +he initial Phase I_IbPAi++erl fer appFeval shall establish n e Gl8V8lenw,en+ n n.Ji+ions Page 7 of 26 Responsible land di,;P wher disturber or RLD means an individual holdinq a certificate issued by the Department who is responsible for carrying out the land- disturbinq activity in accordance with the approved ESC plan. In addition, the RLD may be a Virginia Professional Engineer, Land Surveyor, Landscape Architect, Architect, or Professional Soil Scientist, provided that it is the same licensed professional who sealed and signed the ESC plan. The RLD may be the owner, applicant, permittee, designer, superintendent, project manager, contractor, or any other project or development team member. The RLD must be designated on the ESC plan or permit as a prerequisite for engaging in land disturbance.fr^m +ho r 8Gt „r .Joy ol.,r,r, 8Rt teary whe Will be ; nhaFge eff and F86peRS01918 f.,r .. .,i i+ o Io., .J durst irb;ng M..+ilii+�i .. ro.J by approved plan e @Rt lieu of a plan, WhG: Runoff volume means the volume of water that runs off the land development proiect from a prescribed storm event. Single-family residence means a noncommercial dwelling that is occupied exclusively by one (1) family. Steep slope means a slope greater than 3:1, or thirty-three and one-third (33.3) percent. Q+oh7ized meaRS aR aFea that A_ -An ho 0 8Gt8 J to wi+ho+or,.J r, of o e +., atmesph8FOG onS .,i+h,,,,+s. State permit means an approval to conduct a land -disturbing activity issued by the Board in the form of a state stormwater individual permit or coverage issued under a state general permit. State waters means all waters on the surface and under the ground wholly or partially within or bordering the Ceommonwealth or within its jurisdictions. Town means the incorporated Town of Vinton. Transporting means any moving of earth materials from one place to another place other than such movement incidental to grading, when such movement results in destroying the vegetative ground cover either by tracking or the buildup of earth Page 8 of 26 materials to the extent that erosion and sedimentation will result from the soil or earth materials over which such transporting occurs. Virginia Erosion and Sediment Control Program or VESCP means a program approved by the Board that has been established by a VESCP authority for the effective control of soil erosion, sediment deposition, and non-agricultural runoff associated with a land -disturbing activity to prevent the unreasonable degradation of properties, stream channels, waters, and other natural resources and shall include such items where applicable as local ordinances, rules, permit requirements, annual standards and specifications, policies and guidelines, technical materials, and requirements for plan review, inspection, enforcement where authorized in this article, and evaluation consistent with the requirements of this article and its associated regulations. VESCP pPlan-approving authority means the Director of Community Development or his assignee, depal RgeRt 9f „n;+„ deVelePRgeI# which is responsible for determining the adequacy of a R -plan submitted for land -disturbing activities on a unit or units of lands and for aDDrovina Dlans. VESCP authority or arooram authoritv means Roanoketh-e Ceounty which has adopted a soil erosion and sediment control program that has been approved by the B -board. Water Quality Volume means the volume equal to the first one-half inch of runoff multiplied by the impervious surface of the land development project. Sec. 8.1-4. - Administration of chapter in conjunction with subdivision and zoning ordinances. This chapter shall be administered, where applicable, in conjunction with the county's subdivision and zoning ordinances wherein such apply to the development and subdivision of land within the county or where such apply to development on previously subdivided land within the county. Sec. 8.1-5. - Local erosion and sediment control program. (a) Pursuant to section 62.1-44.15:54 of the Code of Virgini:lGede of ` iFgiRia § 'n' _56-2, the Csounty hereby establishes a VESCP program and -adopts the regulations promulgated by the Board (for the effective control of soil erosion and sediment deposition to prevent the unreasonable degradation of properties, stream channels, waters and other natural resources) and the Virginia Erosion and Sediment Control Handbook, as amended., eferegse6, g6l;deliRes, stay .Ad-6PeeifiGat;ens pFemulgated by the —state „a nd a+or a+;,,., beard- and those more stringent local sfeter MaRageMeRt—criteria which the county board of Page 9 of 26 supervisors, may adopt by resolution and incorporate into the manual of regulations and policies entitled "Stormwater Management Design Manual" and "Design and Construction Standards Manual". (b) In accordance with � 62.1-44.15:52 of the Code of Virginia, any plan approved prior to July 1, 2014 that provides for stormwater management that addresses any flow rate capacity and velocity requirements for natural or man-made channels shall satisfy the flow rate capacity and velocity requirements for natural or man-made channels if the practices are designed to (i) detain the water quality volume and to release it over 48 hours; (ii) detain and release over a 24-hour period the expected rainfall resulting from the one year, 24-hour storm; and (iii) reduce the allowable peak flow rate resulting from the 1.5, 2, and 10 -year, 24-hour storms to a level that is less than or equal to the peak flow rate from the site assuming it was in a good forested condition, achieved through multiplication of the forested peak flow rate by a reduction factor that is equal to the runoff volume from the site when it was in a good forested condition divided by the runoff volume from the site in its proposed condition, and shall be exempt from any flow rate capacity and velocity reauirements for natural or man-made channels (24) For plans approved on and after July 1, 2014, the flow rate capacity and velocity requirements for natural and man-made channels shall be satisfied by compliance with water quantity requirements specified in § 62.1-44.15:28 of the Stormwater Management Act and 9VAC25-870-66 of the Virqinia Stormwater Management Program (VSMP) regulations, unless such land -disturbing activities are in accordance with the grandfathering provisions of the Virginia Stormwater Management Program (VSMP) Regulations. The Csounty hereby designates the D4irector of Csommunity 24evelopment or his assignee as the plan -approving authority. (es)The program and regulations provided for in this chapter shall be made available for public inspection at the office of the D4epartment of Csommunity D4evelopment. (f4) Pursuant to Sec. 62.1-44.15:53 of the Code of Virginia§ 4^�.4, an erosion control plan shall not be approved until it is reviewed by a certified plan reviewer. Inspections of land -disturbing activities shall be conducted by a certified inspector. The erosion control program of the Csounty shall contain a certified program administrator, a certified plan reviewer, and a certified inspector, who may be the same person. Page 10 of 26 Sec. 8.1-6. - Regulated land -disturbing activities; submission and approval of plans; contents of plans. (a) Except as provided herein, no person may engage in any land -disturbing activity until he or she has submitted to the D4epartment of Ceommunity 24evelopment an erosion and sediment control plan for the land -disturbing activity and such plan has been approved by the VESCP authority. No approval to begin a land-disturbinq activity will be issued unless evidence of state permit coverage is obtained where it is required. Where land -disturbing activities involve lands under the jurisdiction of more than one VESCP , an erosion and sediment control plan, at the option of the applicant, may be submitted to the Departmentheard for review and approval rather than to each jurisdiction concerned. The Department may charge the applicantC y a fee sufficient to cover the cost associated with conducting the review. -Where the land -disturbing activity results from the construction of a single-family residence, an agreement in lieu of a plan may, at the discretion of the County, be substituted for an erosion and sediment control plan if executed by the plan- approvinq authority. Additional requirements are given below: (1) Where the land -disturbing activity, from the construction of a single-family residence, results in h^+,.,^^n NVe f„^ h,,r,+red (2,599) squaFe +^^+ armless than five thousand (5,000 ) square feet RAdler tIA'e �z of disturbedarea, an "agreement in lieu of a plan” may h^ S„hS+;+„+^,+ +^r ^ n,+ �^,+i,,,^r+ ^RtFel ^Io., i+ ^ ^„+^,+ by the ^I^r apffeViRg „+heFi+ shall be accompanied by a plot plan that meets the County Buildinq Permit Plot Plan requirements. (2) Where the land -disturbing activity, from the construction of a single-family residence, results in betweer--five thousand (5,000) square feet or more a444 f„-^ &8d (599) to r h,_'n..R_Qd fi#Y (759) ^„h;^ y aFds of disturbed area, an "agreement in lieu of a plan” shall be accompanied by e 44--r-a plot plan that meets the County Building Permit Plot Plan`��F^�^�a I R'feFn, c+^+^,.,; +^ r^,+o for h,,;IG;r^ .,;+ PIG)t WaR requirements, prepared by a sertif+ed responsible land disturber, i eF aR 8RgiR88F8Gl ^I^^ pFepaFed b Virginia Professional Engineer, Land Surveyor, Landscape Architect, Architect, or Professional Soil ScientistFef866meRal ^r+;+^ + '^n +�^^r^ a sshewiRg ;-;^d ^di^,^^+ r+r^I . A eerfified responsible land disturber must also be provided and identifieded. _(3) F2 ep FesstFlfis-On tentheR d (49,909) efeet _ h6IGIF8d +i++„ (750) hi. , �r +� of ,+ice h� + ;Tcrr o��i--rneT� zrr ;u ter' Fea ,�'r�reFOSien--arrcr Page 11 of 26 lie era+ G A-RtFeI plan Is t I,o „hr„;++e .The County may require additional information, or may decline to execute an agreement in lieu of a plan and may require an erosion and sediment control plan in instances where, in the County's opinion, it is necessaryappf� aR eres+e^ '^doo.Jir. o^+ eRtFel NaR "' need -le + '^ er'+er to properly protect downstream properties or the environment. v,hip.. has bP@R r F@d by a FGf000 Glial @RgOR88F GF A.or+;f,o�l ar448 R„r ,+ims+-url,o,+ .,f than ten +I,,,wsand (10 nnn� elleyv te d-lete.P.P.A.i.n.e F8q6liF8M8RtS-fer the �.. safe deet �9 8 Exempt fFem CQ_C DlaRj Fed &99A -988 plaR� p8FMitfee; *b6lildiRg peFmit plet plan r F8d X889— 580— oer#,iedRlE, *b6l i l„diR g or+ fo + R' --D, or+if 8d �T.; perpAit fee Page 12 of 26 rety; a *bYi1diRg r, mit plet ploy, if F8GI r8d by +ho plo r,+; (c) An erosion and sediment control plan shall be filed for a development and the buildings constructed within, regardless of the phasing of construction. (d) If individual lots or sections in a residential development are being developed by different property owners, all land -disturbing activities related to the building construction shall be covered by an erosion and sediment control plan or an "Agreement in Lieu of a Plan" signed by the property owner. The property owner is responsible for complying with the provisions of (a) or (b) above for each lot to obtain an erosion and sediment control permit. (e) Land -disturbing activity of less than two thousand five hundred (2,500) square feet on individual lots in a residential development shall not be considered exempt from the provisions of this ordinance, if the total land -disturbing activity in the development is equal to or greater than two thousand five hundred (2,500) square feet. (f4) The standards contained with the "Virginia Erosion and Sediment Control Regulations," and The Virginia Erosion and Sediment Control Handbook, as amended and those more stringent local r.,r, aag8M8Rt criteria which the B -board of Ssupervisors of the County, may adopt by resolution and incorporate into the manual of regulations and policies entitled "Stormwater Management Design Manual" and "Design and Construction Standards Manual" are to be used by the applicant when making a submittal under the provisions of this chapter and in the preparation of an erosion and sediment control plan. -_In cases where one standard conflicts with another, the more stringent applies. The VESCP plan -approving authority, in considering the adequacy of a submitted plan, shall be guided by the same standards, regulations and guidelines. The plan appFeViRg u+heFity mwa-ve edify o of +ho r ..lo+i r. r,o that aFe r.RtFel Page 13 of 26 (ge)The VESCP plan -approving authority shall review erosion and sediment control plans submitted to it and grant written approval within 60 days of the receipt of the plan if it determines that the plan meets the requirements of the Erosion and Sediment Control Law and the Board's regulations, and if the person responsible for carrying out the plan certifies that he will properly perform the measures included in the plan and will conform to the provisions of this ordinance. In addition, as a prerequisite to engaging in the land -disturbing activities shown on the approved plan, the person responsible for carrying out the plan shall provide the name of the responsible land disturber, to the program authority, as provided by § 62.1- 44.15:52, of the Virginia Erosion and Sediment Control Law, who will be in charge of and responsible for carrvinq out the land -disturbing activity. Failure to provide the name of the responsible land disturber, prior to engaging in land -disturbing activities may result in revocation of the approval of the plan and the person responsible for carrying out the plan shall be subject to the penalties provided in this ordinance. However, the VESCP plan -approving authority may waive the certificate of competence requirement for an agreement in lieu of a plan for construction of a single family residence. If a violation occurs during the land -disturbing activity, then the person responsible for carrying out the agreement in lieu of a plan shall correct the violation and provide the name of the responsible land disturber, as provided by 62.1-44.15:52 of the Virginia Erosion and Sediment Control Law. Failure to provide the name of the responsible land disturber shall be a violation of this chapter. leA-al nfrel Rd of fho nese„ =e�r�lGaFFYORg 6if the nlon -te,o � � sef#' s-� �f� heA- She Vwill--pFep2F'y p8FfeF fho Ad RAPIOPARAt nr.nfrG the Plan and Will GeRfr,rw, fr. fho P GffhOo nhapter. When the plan is determined to be inadequate, written notice of disapproval stating the specific reasons for disapproval shall be communicated to the applicant within forty-five (45) days. The notice shall specify the modifications, terms and conditions that will permit approval of the plan. If no action is taken by the plan -approving authority within the time specified above, the plan shall be deemed approved and the person authorized to proceed with the proposed activity. Page 14 of 26 ral+ioo pFevi,+o,+ in thio GhapteF The VESCP authority shall act on any erosion and sediment control plan that has been previously disapproved within 45 days after the plan has been revised, resubmitted for approval, and deemed adequate. r2 +Fe1��eR+� 9.1 3(t)(10) .,f thio Chapter, if o 0AIR40r,nAGAI-IrSd riRg the w_ Af o Dlap" sh-All oma+ +ho v 'AlAt' n And p vide the narne Af on helding o fi..o+o .,f .. OG1 h�� +i.,r 1!1 1 561 Af +ho o+o+o o ., .J se#� ^etc�;�as�a ��es thio Ghapt8F Ug) The VESCP authority may require changes to aan,444 approved plan may be when: (1) The inspection reveals that the plan is inadequate to satisfy applicable regulations; or (2) The person responsible for carrying out the plan finds that because of changed circumstances or for other reasons the approved plan cannot be effectively carried out, and proposed amendments to the plan, consistent with the requirements of this chapter, are agreed to by the plan approving authority and the person responsible for carrying out the plan. (L4)Variances: The VESCP plan -approving authority may waive or modify any of the standards that are deemed to be inappropriate or too restrictive for site conditions, by granting a variance. A variance may be granted under these conditions: (1) At the time of plan submission, an applicant may request a variance to become part of the approved erosion and sediment control plan. The applicant shall explain the reasons for requesting variances in writing. Specific variances which are allowed by the plan -approving authority shall be documented in the clan. (2) During construction, the person responsible for implementing the approved plan may request a variance in writing from the plan -approving authority. The plan -approving authority shall respond in writing either approving or disapproving such a request. If the plan -approving authority does not approve a variance within 10 days of receipt of the request, the request shall be considered to be disapproved. Following disapproval, the applicant may resubmit a variance request with additional documentation. (3) The VESCP authority shall consider variance requests judiciously, keeping in mind both the need of the applicant to maximize cost Page 15 of 26 effectiveness and the need to protect off-site properties and resources from damage. (1) In order to prevent further erosion, the Ceounty may require aFea.the property owner of land identified by the County as an erosion impact area to immediately take actions to minimize the delivery of sediment onto neighboring properties or into state waters, and to prepare and submit to the County an Erosion and Sediment Control Plan that details how the erosion impact area will be Permanently stabilized. Failure by the property owner to comply with County directions to immediately take actions to minimize the delivery of sediment onto neighboring properties or into state waters; or failure to submit an Erosion and Sediment Control Plan within a reasonable time period set by the County; or failure to implement the Erosion and Sediment Control Plan after approval by the County within a reasonable time period set by the County shall be a violation of this ordinance. Such violation shall be subiect to all of the penalties and other leaal actions contained in Section 8.1-10. (m+)When a land -disturbing activity will be required of a contractor performing construction work pursuant to a construction contract, the preparation, submission, and approval of an erosion control plan shall be the responsibility of the owner. (nt) In accordance with the procedure set forth in §62.1-44.15:55 (E) of the Code of Virginia, any person engaging, in more than one jurisdiction, in the creation and operation of wetland mitigation or stream restoration banks, which have been approved and are operated in accordance with applicable federal and state guidance, laws, or regulations for the establishment, use, and operation of wetland mitigation or stream restoration banks, pursuant to a mitigation banking instrument signed by the Department of Environmental Quality, the Virginia Marine Resources Commission, or the U.S. Army Corps of Engineers, may, at the option of that person, file general erosion and sediment control specifications for wetland mitigation or stream restoration banks annually with the Board for review and approval consistent with guidelines established by the Board. Approval of general erosion and sediment control specifications does not relieve the owner or operator from compliance with any other local ordinances and regulations including requirements to submit plans and obtain permits as may be required by such ordinances and regulations. Page 16 of 26 Th hall have sixty (69) day Whi..h to a e the s ..ifi..a+i.,. -s If r, a..fi.,., TT Ol"I'laTl"I"!Q"PC��. "fl\T�9GTCIGp 0s tan R by th ar.J Y. ithiR 69 days, tho S GifiGatieRs; shall be, deae ed a e The heard shall have the autheFity to 8Rfe FGe a ped s ..ifi..atieRS (2k)State agency projects are exempt from the provisions of this chapter, except as provided for in the Code of Virginia, Sec. 62.1-44.`I_ 56§49-. 564. (pl) If the grade of a site is more than thirty-three and one-third (33.3) percent, refer to the International Building Code, Chapter 18, as amended, for foundation clearances from slopes f„r Maar, deer GI8V8l„r,r 8Rt r RtS (qm) Cut slopes or fill slopes shall not be greater than 2:1 (horizontal:vertical), unless a geotechnical report is provided for the proposed slopes. (4) Cut slopes or fill slopes shall not be greater than twenty-five vertical feet in height, unless a geotechnical report is provided for the proposed slopes. Cut slopes or fill slopes less than or equal to 3:1 (horizontal:vertical) may exceed twenty-five (25) vertical feet in height and shall not require a geotechnical report. (se)For any cut slopes or fill slopes greater than or equal to 2:1 (horizontal:vertical) ora44 4 greater than or equal to twenty-five (25) vertical feet in height with a slope greater than 3:1 (horizontal:vertical), as -built plans showing that the finished geometry, based on a field survey performed by a licensed surveyor, is in substantial conformity with the design shall be provided to the plan -approving authority. (Ip) Fill materials, compaction methods and density specifications shall be indicated on the site development plans. Fill areas intended to support structures shall also be indicated on the site development plans. r,,mpaGtieR fos 866+46 (PeF V -DOT $ta.,�ac) ?hall be s-Hhw, Otted to the plan a iltheFity. (14q)Development plans for all new subdivisions shall show proposed lot grades to ensure positive drainage. Sec. 8.1-7. — Special provisions for land -disturbing activities that disturb less than ten thousand (10,000) square feet Page 17 of 26 (a)_ This section applies to all land -disturbing activities that disturb_ less than ten-_- - thousand (10,000) square feet, except as herein described for residential development in Section 8.1-6k). (b) Land -disturbing activities shall meet all of the requirements of this ordinance, except for the following:. (1) The adequacy of downstream channels and pipes are not required to beh analyzed and verified. (2) No stormwater management measures to address any flow rate capacity or velocity requirements for downstream natural or man-made channels shall be required. (3) An agreement in lieu of a plan may, at the discretion of the County, be substituted for an erosion and sediment control plan if executed by the plan - approving authority. All of the requirements of Section 8.1-6(b) shall apply. This provision expands the use of an agreement in lieu of, beyond a single-family residence, to all land -disturbing activities that disturb less than ten thousand (10,000) square feet. Formatted: Font: Formatted: IistO, Indent: Left: 0", First line: 011 Clarified meaning. Formatted: Default Paragraph Font, Font: 12 pt Formatted: Font: Formatted: IistO, Indent: Left: 0.56", First line: 0" (c) Nothing in this section shall be construed to negate any requirements of the.- - - Formatted: IistO, Indent: Left: 0", First line: Stormwater Management Ordinance of the County of Roanoke, where applicable.. 011 Formatted: Font: Sec. 8.1-8. - Permits; fees; suretybs4d4g; etc. (a) Agencies authorized under any other law to issue grading, building, or other permits for activities involving land -disturbing activities may not issue any such permit unless the applicant submits with his application an approved erosion and sediment control plan_-a4d-certification that the plan will be followed and evidence of state permit coverage where it is required. (b) No person shall engage in any land -disturbing activity until he has acquired a land - disturbing permit, unless the proposed land -disturbing activity is specifically exempt from the provisions of this chapter, and has paid the fees and posted the required s u rety4. (c) Fees. An applicant requesting permission to begin land -disturbing activity pursuant to this article shall pay the following fees to cover the administrative expense of review, permitting, and inspection. Disturbed Area (Square Feet) Fee Less than 5,000 $25.00 5,000 - 9,999 $50.00 Page 18 of 26 10,000 — or greater $100.00 + $100.00 per disturbed acre, or portion of an acre F2 - - - AAd/Q S,h+e - - fees Cap - - - Reg64^FReP.t- - - - - - Formatted: Font: Arial, 12 pt, Highlight €eet Yards 42-69�------------------ ------ Mqa_e (td)No land -disturbing permit shall be issued until the applicant submits with the application an approved erosion and sediment control plan or agreement in lieu of an approved erosion and sediment control plan and certification that the plan will be followed. - Formatted: Font: Arial, 12 pt, Highlight Formatted: Font: Arial, Highlight � Formatted: Font: Arial, 12 pt, Highlight Formatted: Font: Arial, Highlight Formatted: Font: Arial, 12 pt, Highlight Formatted: Font: Arial, 12 pt, Highlight Formatted: Font: Arial, Highlight Formatted: Font: Arial, Highlight Formatted: Font: Arial, 12 pt, Highlight Formatted: Font: Arial, 12 pt, Highlight Formatted: Font: Arial, Highlight Formatted: Font: Arial, Highlight Formatted: Font: Arial, 12 pt, Highlight Formatted: Font: Arial, Highlight Formatted: Font: Arial, 12 pt, Highlight Formatted: Font: Arial, 12 pt, Highlight �,, Formatted: Font: Arial, Highlight J Formatted: Font: Arial, 12 pt, Highlight Formatted: Font: Arial, Highlight (f) Surety�eF►d�. All applicants forpermits shall provide to the Ceounty a performance Revised to maintain bond, cash escrow, or an irrevocable letter of credit acceptable to the Ddirector of 10% bond contingency. Csommunity Ddevelopment or his assignee, to ensure that measures could be taken by the Csounty at the applicant's expense should the applicant fail, after proper notice, within the time specified to initiate or maintain appropriate conservation measures required of him as a result of his land -disturbing activity. The amount of the -h^^d^r ^*"^.r &eG ##surety for performance shall ^ edbe the total of the estimated cost to initiate and maintain appropriate conservation action based on unit price for new public or private sector construction in the locality plus a contingency for ^tithe County's administrative costs and inflation. The Page 19 of 26 contingency shall be 10% of the total estimated cost to initiate and maintain the appropriate conservation action, Y41 july 1,291?. ORjuly 1, 2017 and thprpa#e�, the ...,+O.,..^.,..., Shall be 75% Th^ a n+ ..f 5...,+E.,..^.,5., ..r.da.,S^ ,.,i+" Title 1 7 GhapteF 22 Ar+i Sl^ 41 (SeGtO..., 15.2 2241 et S^.. ) ..f the f`ede ..f Vomm ,i (1950) as aimeradded. . Should it be necessary for the Csounty to take such conservation action, the Csounty may collect from the applicant any costs in excess of the amount of the surety held. Within 60 days of adequate stabilization and completion of all other site requirements and permit requirements, including submission of written request by the permittee, as +^+^r...^^ by the RdiFe^+„r „f C-A-G..,.AHRi+„ Rdey^I,,.,.,,^.,+ „r his aseigRee-such surety"^^�' c" ^ r^++^r ^f ^r^ +;+�_ or the unexpended or unobligated portion thereof shall be either refunded +^ the a^^c^a^+ or terminated. (he)These requirements are in addition to all other provisions relating to the issuance of permits and are not intended to otherwise affect the requirements for such permits. Sec. 8.1-99. - Monitoring, reports, and inspections (a) The responsible land disturber, as provided in § 62.1-44.15:52, shall be in charge of and responsible for carrying out the land -disturbing activity and provide for periodic inspections of the land -disturbing activity. The Csounty may require the person responsible for carrying out the plan and9F the r^S.,.,.,Sihl^'a^,+ diSt"Ph^r to monitor and malntahe land -disturbing activity. Theerp son responsible for carrying out the plan4^4d4 r"ter will maintain records of these inspections and maintenance, to ensure compliance with the approved plan and to determine whether the measures required in the plan are effective in controlling erosion and sedimentation. (b) The D4epartment of Csommunity 24evelopment shall periodically inspect the land - disturbing activity in accordance with 9VAC25-840-60 of the Virginia Erosion and Sediment Control Reaulationsas-feg4i=F ;,;Qer +�„�-pia, to ensure compliance with the approved plan and to determine whether the measures required in the plan are effective in controlling erosion and sedimentation. The owner, permittee, or person responsible for carrying out the plan shall be given notice of the inspection. If the D4irector of Ceommunity 24evelopment,. or his assignee,, determines that there is a failure to comply with the plan or if the plan is determined to be inadequate, notice shall be served upon the permittee or; person responsible for carrying out the plan ^r the r^S^^.,S,hl^ la^,+ r,,StuFbeF by registered or certified mail to the address specified in the permit application or in the plan certification, or by delivery at the site of the land -disturbing activities to the agent or employee supervising such activities. The notice shall specify the measures needed to comply with the plan and shall specify the time within which such measures shall be completed. Upon failure to Page 20 of 26 comply within the specified time, the permit may be revoked and the permittee shall be deemed to be in violation of this chapter and, upon conviction, shall be subject to the penalties provided by this chapter. (c) Upon issuance of an inspection report denoting a violation of Va. Code §§ 62.1- 44.15:55, -44.15:56, the Director of Community Development, or his assignee, may, in conjunction with or subsequent to a N+4otice to Ceomply as specified in this chapter, issue a4 Stop Work Oarder requiring that all or part of the land -disturbing activities permitted on the site be stopped until the specified corrective measures have been taken. May, 1R GeRj61RGtieR thiS GhapteF, issue aR eFG18F F8q61iFiRg that all eF part Af the ';;A o hovo hour, +oke4 If land -disturbing activities have commenced without an approved plan or proper permits, the D4irector of Ceommunity G'8VrDevelopment or his assignee may, in conjunction with or subsequent to a N+Rotice to Csomply as specified in this chapter, issue a Stop Work 4:�--049rder requiring that all of the land -disturbing and/or construction activities be stopped until an approved plan or any required permits are obtained. Failure to comply will result in civil charges or penalties as outlined in section 8.1-109 of this chapter. Where the alleged noncompliance is causing or is in imminent danger of causing harmful erosion of lands or sediment deposition in waters within the watersheds of the Ceommonwealth, or where the land -disturbing activities have commenced without an approved plan or any required permits, such a Stop Work +:�--Oarder may be issued without regard to whether the permittee has been issued a N+Rotice to Csomply as specified in this chapter. Otherwise, such a Stop Work 04girder may be issued only after the permittee has failed to comply with such as N+Rotice to Ceomply.--T The Stop Work Oarder shall be served in the same manner as as N+Rotice to Csomply, and shall remain in effect for a period of seven (7) days from the date of service pending application by the CountV8RfeFGiRg aut4e i+„ or permit holder for appropriate relief to the Ceircuit Csourt. The County shall serve such Stop Work Oarder for disturbance without an approved plan or permits upon the owner by mailing with confirmation of delivery to the address specified in the land records. Said Stop Work Oarder shall be posted on the site where the disturbance is occurring, and shall remain in effect until permits and plan approvals are secured, except in such situations where an agricultural exemption applies. Page 21 of 26 If the alleged violator has not obtained an approved plan or any required -permits—,-- within permits—,--within seven (7) days from the date of service of the Stop Work Oerder -the_ D4irector of Csommunity 24evelopment or his assignee may issue as Stop Work O' - girder to the owner requiring that all construction and other work on the site, other than corrective measures, be stopped until an approved plan and any required permits have been obtained. Such an order shall be served upon the owner by registered or certified mail to the address specified in the permit application or the land records of the Csounty. Formatted: Font: Arial Formatted: Normal, Justified, Indent: Left: 0.3", Space Before: 12.6 pt, Line spacing: Exactly 12.85 pt, Font Alignment: Baseline Formatted: Font: Arial Formatted: Font: Arial The owner may appeal the issuance of a Stop Work Off --girder to the Csircuit C_sourt_ Formatted: Font: Arial of the Csounty. Any person violating or failing, neglecting or refusing to obey a Stop Work O. -R -girder issued by the D4irector of Csommunity 24evelopment or his - Formatted: Font: Arial assignee may be compelled in a proceeding instituted in the Csircuit Ceourt of the Csounty to obey same and to comply therewith by injunction, mandamus or other appropriate remedy. Upon completion and approval of corrective action or obtaining an approved plan or any required permits, the Stop Work Oerder shall immediately - Formatted: Font: Arial be lifted. Nothing in this section shall prevent the D4irector of Csommunity 24evelopment or his assignee from taking any other action authorized by this chapter. Sec. 8.1-10-9. - Penalties, injunctions, and other legal actions. (a) Violators of this chapter shall be guilty of a Cslass I misdemeanor. (b) Civil penalties: (1) A civil penalty in the amount listed on the schedule below shall be assessed for each violation of the respective offenses: a. Commencement of land disturbing activity without an approved plan as provided in section 8.1-6 shall be one thousand dollars ($1,000.00) per day. b. Vegetative measures. Failure to comply with items 1, 2 an4 3, or 5 of the minimum standards shall be three hundred dollars ($300.00) per violation per day. c. Structural measures. Failure to comply with items -1-, 4, 6, 7, 8, 9, 10, 11, 45,. a -R4 17, or 18 of the minimum standards shall be three hundred dollars ($300.00) per violation per day. d. Watercourse measures. Failure to comply with items 12, 13, 14 and 15 of the minimum standards shall be three hundred dollars ($300.00) per violation per day. e. Underground utility measures. Failure to comply with item 16(a) aFld�si (s) shall be three hundred dollars ($300.00) per violation per day. f. Failure to obey a stop work order shall be one thousand dollars ($1,000) per day. Page 22 of 26 g. Failure to stop work when permit revoked shall be one thousand dollars ($1,000) per day. (2) Each day during which the violation is found to have existed shall constitute a separate offense. However, in no event shall a series of specified violations arising from the same operative set of facts result in civil penalties which exceed a total of ten thousand dollars ($10,000.00), except that a series of violations arising from the commencement of land -disturbing activities without an approved plan for any site shall not result in civil penalties which exceed a total of ten thousand dollars ($10,000.00). The assessment of civil penalties according to this schedule shall be in lieu of criminal sanctions and shall preclude the prosecution of such violation as a misdemeanor under subsection (a) of this section. (c) The D4irector of Csommunity 24evelopment or his assignee, or the owner of property which has sustained damage or which is in imminent danger of being damaged, may apply to the Csircuit Csourt of the Csounty to enjoin a violation or a threatened violation of Va. Code 62.1-44.15:55, 62.1-44.15:564�, without the necessity of showing that an adequate remedy at law does not exist. However, an owner of property shall not apply for injunctive relief unless (i) he has notified in writing the person who has violated the local program, and the program authority, that a violation of the local program has caused, or creates a probability of causing, damage to his property, and (ii) neither the person who has violated the local program nor the program authority has taken corrective action within fifteen days to eliminate the conditions which have caused, or create the probability of causing, damage to his property. (d) In addition to any criminal penalties provided under this chapter, any person who violates any provision of this chapter may be liable to the Csounty in a civil action for damages. (e) Civil penalty enumerated. Without limiting the remedies which may be obtained in this section, any person violating or failing, neglecting, or refusing to obey any injunction, mandamus or other remedy obtained pursuant to this section shall be subject, in the discretion of the Csourt, to a civil penalty not to exceed two thousand dollars ($2,000.00) for each violation. A civil action for such violation or failure may be brought by the Csounty. Any civil penalties assessed by a Csourt shall be paid into the Ttreasury of the Csounty, except that where the violator is the locality itself, or its agent, the Csourt shall direct the penalty to be paid into the state treasury. (f) With the consent of any person who has violated or failed, neglected or refused to obey any regulation or condition of a permit or any provision of this chapter, the Csounty may provide for the payment of civil charges for violations in specific sums, not to exceed the limit specified in subsection (b)(2) of this section. Such civil Page 23 of 26 charges shall be instead of any appropriate civil penalty which could be imposed under subsection (b) or (e). (g) The Ceounty's Aattorney shall, upon request of the Ceounty eF the norFRit "'+take legal action to enforce the provisions of this chapter. (h) Compliance with the provisions of this chapter shall be prima facie evidence in any legal or equitable proceeding for damages caused by erosion, siltation or sedimentation that all requirements of law have been met, and the complaining party must show negligence in order to recover any damages. Sec. 8.1-118. — Hearings and AppealsAppeals and 61diGial r (a) Hearings verbatim .record. of the oroceedinas of such heari aminlstrator, —a nu Lne t--- Formatted: Normal, Left, Indent: Left: 0.25", Hanging: 0.31", Right: 0", No bullets or numbering, Allow hanging hall be taken and filed punctuation, Tab stops: Not at 0.58° I and read as in actions Formatted Formatted Page 24 of 26 (b) Appeals - - Formatted: Font: Arial, 12 pt Formatted: Indent: First line: 0" Formatted Sec. 8-1.124-. - Civil violations, summons, generally. (a) The D4irector of Community Development, or his assignee, shall prepare an appropriate erosion and sediment control civil violation summons for use in enforcing the provisions of this chapter. (b) Anyep rson+RsPesfe of the VESCP plan approving authority charged with enforcing this chapter shall serve upon any owner or permittee in violation of this chapter, a summons notifying the owner or permittee of said violation. If unable to serve the owner or permittee in person, the inspector may notify by summons an owner or permittee committing or suffering the existence of a violation by certified, return receipt requested mail, of the infraction. The Ceounty Ssheriffs office may also deliver the summons. The summons shall contain the following information: (1) The name and address of the person charged. (2) The nature of the violation and chapter provision(s) being violated. (3) The location, date, and time that the violation occurred, or was observed. (4) The amount of the civil penalty assessed for the violation. Page 25 of 26 (5) The manner, location, and time that the civil penalty may be paid to the Csounty. (6) The right of the recipient of the summons to elect to stand trial for the infraction and the date of such trial. (c) The summons shall provide that any person summoned for a violation may, within five (5) days of actual receipt of the summons or, within ten (10) days from the date of mailing of the summons, elect to pay the civil penalty by making an appearance in person, or in writing by mail to the Csounty Ttreasurer's office and, by such appearance, may enter a waiver of trial, admit liability, and pay the civil penalty established for the violation charged and provide that a signature to an admission of liability shall have the same force and effect as a judgment in court; however, an admission shall not be deemed a criminal conviction for any purpose. (d) If a person charged with a violation does not elect to enter a waiver of trial and admit liability, the Csounty shall cause the Ssheriff of the Csounty to serve the summons on the person charged in the manner prescribed by law. The violation shall be tried in Ggeneral D4istrict Ceourt in the same manner and with the same right of appeal as provided for in Title 8.01 of the Code of Virginia. In any trial for a scheduled violation authorized by this section, it shall be the burden of the Csounty to show the liability of the violator by the preponderance of the evidence. Any admission of liability, or finding of liability shall not be a criminal conviction for any purpose. (e) The remedies provided for in this section are cumulative, and are not exclusive and, except as provided above, shall be in addition to any other remedies by law. (f) The owner or permittee may pay the civil penalty to the Ttreasurer prior to the trial date, provided he also pays necessary court costs in addition to the civil penalty. (g) Within the time period prescribed in (c), above, the owner or permittee, may contest the violation by presenting it to the D4irector of Community Development, who shall certify the contest in writing, on an appropriate form, to the Ggeneral D4istrict Cso u rt. (h) Failure to pay the civil penalty, or to contest the violation, within the time period prescribed in (c), above, shall result in the immediate issuance of a Sstop W� ork Oerder and the revocation of the permit, if any. 2. That this ordinance shall be in full force and effect from and after its adoption. Page 26 of 26 Summary of proposed changes to Stormwater Management Ordinance BACKGROUND: In 2014, Roanoke County revised the local stormwater management ordinance to comply with current state law and regulations. DEQ provided some minor comments on the local ordinance that were not sent to the County until after the ordinance was passed. DEQ requested that the County make their requested changes this year. Since the ordinance needs to be revised, staff is taking this opportunity to proposed changes to improve the program, based on our first year of operating the local stormwater management program. SUMMARY OF PROPOSED SIGNIFICANT ORDINANCE CHANGES 1. Some minor revisions requested by DEQ that do not have any significant impact. 2. The Town of Vinton desires to relinquish their responsibility to be a local VSMP authority. Roanoke County has agreed to accept the role of local authority for Vinton. The Ordinance has been revised to reflect this. 3. Section 23-3.7 — revised to remove requirement to submit formal maintenance agreement for BMPs designed to serve runoff from an individual single-family residential lot. Instead, County will use targeted outreach and education. 4. Section 23-6.3 — revised to remove requirement to submit record drawings where formal maintenance agreements are not provided (see item 3 above). 5. Section 23-6.3 — Require supplemental digital file to accompany record drawings. This is an additional requirement to assist staff in maintaining and improving GIS and other records. 6. Section 23-7.1 — Requires property owners that have BMPs to perform maintenance, even if there is no recorded maintenance agreement. 7. Section 23-9.2 — Changed some terminology (Notice of Violation to Notice to Comply) to better coordinate terminology with erosion and sediment control ordinance. 8. Section 23-9.4 — Added provisions for civil penalties and charges to provide a more effective enforcement mechanism and to better align with enforcement procedures used in erosion and sediment control program. Have revised penalty amounts to better align with those that are in the erosion and sediment control ordinance. REVISED JANUARY 26, 2016 - Formatted: Font: (Default) +Body (Calibri), Bold Stormwater Management Ordinance from Chapter 23 of the County of Roanoke Code Introduction........................................................................................................... Section 23-1 General Provisions.......................................................................... 23-1.1 Title and Authority............................................................................. 23-1.2 —Purpose ................................................................................................ 23-1.3 Applicability.........................................................................._............. 23-1.4 Compatibility with Other Requirements ............................................. 23-1.5— Severability 3-1.5— SeverabiIity.............................................................._........................... 23-1.6 Stormwater Management Technical Criteria for Regulated Land Disturbance Activities....._— ......................................................................... 23-1.7 Stormwater Management Technical Criteria for Regulated Land Disturbance Activities: Grandfathered Projects and Projects subject- tothe Provisions of 9VAC25-870-47B...................................................... 23-1.8 Stormwater Management Design Manual ......................................... 23-1.9 County Right of Entry........................................................................ Section 23-2 Definitions........................................................................................ Section 23-3 Program Permit Procedures and Requirements .......................... 23-3.1 Permit Required................................................................................ 23-3.2 Permit Application Contents.............................................................. 23-3.3 Stormwater Pollution Prevention Plans ............................................. 23-3.4 Pollution Prevention Plans................................................................. 23-3.5 Stormwater Management Plans ........................................................ 23-3.6 Comprehensive Stormwater Management Plans and Regional Stormwater Management Facilities ................................................... 23-3.7 Stormwater Management Facility Maintenance Agreements ............ 23-3.8 Performance Securities..................................................................... 23-3.9 Fees.................................................................................................... 23-3.10 Permit Application Procedure.......................................................... Section 23-4 Exceptions to Stormwater Management Requirements .............. Section 23-5 Property Owner Responsibilities for Drainage Ways .................. Section 23-6 Construction Inspection................................................................. 23-6.1 Notice of Construction Commencement ............................................ 23-6.2 Periodic Construction Inspection....................................................... Page 1 of X4839 REVISED_ JANUARY 26, 2016 - Formatted: Font: (Default) +Body (Calibri), Bald 23-6.3 Final Inspection and Record Documentation Page 2 of 274039 REVISED JANUARY 26, 2016 - - Formatted: Font: (Default) +Body (Calibri), Bold Section 23-7 Post Construction Inspection, Maintenance and Repair Of Stormwater Management Facilities ............................................ 23-7.1 Maintenance Inspections of Stormwater Management Facilities....... 23-7.2 Records of Inspection, Maintenance and Repair ................................. Section 23-8 Hearings and Appeals......................................................... ............. 23-8.1 —Hearings..................................................._.................... ................... 23-8.2Appea Is.............................................................................................. Section 23-9 Enforcement and Penalties............................................................ 23-9.1 —Violations........................................................................................... 23-9.2 Notice to Comply .................................................................................... 23-9.3 Stop Work Orders ......................................................................... 23-9.4 Civil and Criminal Penalties............................................................... 23-9.5 Restoration of Lands......................................................................... 23-9.6 Holds on Certificate of Occupancy .............................. : ................. Page 3 of 274039 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald Chapter 23 Stormwater Management Ordinance County of Roanoke, Virginia INTRODUCTION The County of Roanoke is home to a vast array of scenic natural resources, from the mountains that span our landscape to the streams that flow through our valleys. This picturesque environment has embraced generations of citizens while drawing in more newcomers every year. The continual increase in population aids in the growth and development of this area, improving jobs and enhancing economic stability. Yet, intensive development can degrade the beautiful natural resources that make the County so special. Inadequate management of stormwater runoff from land -disturbing activities and development in watersheds increases flood flows and velocities, erodes and/or silts stream channels, pollutes water, overloads existing drainage facilities, undermines floodplain management in downstream communities, reduces groundwater recharge, and threatens public safety. More specifically, surface water runoff can carry pollutants into receiving waters. The Roanoke River and many of its tributaries inside the County are listed as impaired waters by the Virginia Department of Environmental Quality (DEQ). Many future problems can be avoided through proper stormwater management, and the County is dedicated to preventing the damaging effects that uncontrolled stormwater may present. The lands and waters of Roanoke County are valuable natural resources that need to be protected. The County finds that it is in the public interest to establish a stormwater management program. Pursuant to Code § 62.1-44.15:27, this ordinance is part of an initiative to integrate the County of Roanoke's stormwater management requirements with the County of Roanoke's erosion and sediment control (Chapter 8.1) and floodplain management (Section 30-74) requirements into a unified stormwater program. The unified stormwater program is intended to facilitate the submission and approval of plans, issuance of permits, payment of fees, and coordination of inspection and enforcement activities into a more convenient and efficient manner for both the County of Roanoke and those responsible for compliance with these programs. Page 4 of 274039 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald SECTION 23-1 GENERAL PROVISIONS Section 23-1.1 TITLE AND AUTHORITY A. This ordinance shall be known as the "Stormwater Management Ordinance of the County of Roanoke, Virginia." B. Pursuant to § 62.1-44.15:27 of the Code of Virginia, the County of Roanoke hereby establishes a Virginia Stormwater Management Program (VSMP) for land -disturbing activities within Roanoke County and within the Town of Vinton_ - Extending applicability and adopts the applicable Regulations that specify standards and specificationsofOrdinance toinclude the Town ofVinton. for VSMPs promulgated by the State Water Control Board (State Board) for the purposes set out in Section 23-1.2 of this ordinance. The County of Roanoke hereby designates the Director of Community Development as the Administrator of its Virginia Stormwater Management Program. Section 23-1.2 PURPOSE *sib, ""le The purpose of this ordinance is to promote and protect the general health, safety, and welfare of the citizens of the County and to protect property, state waters, stream channels, and other natural resources from the potential harm of unmanaged stormwater, and to establish requirements whereby stormwater is managed to protect water quality and downstream property owners. This ordinance provides the framework for the administration, implementation, and enforcement of the provisions of the Virginia Stormwater Management Act (VSMA) and delineates the procedures and requirements to be followed in connection with the permits issued by the Administrator; Section 23-1.3 APPLICABILITY A. Except as provided herein, no person may engage in any land -disturbing activity until a permit has been issued by the Administrator in accordance with the provisions of this ordinance. B. A stormwater management plan, or an agreement in lieu of a stormwater management plan, shall be reviewed and approved by the Administrator prior to permit issuance. C. Notwithstanding any other provisions of this ordinance, the following activities are exempt, unless otherwise required by federal law: Page 5 of 274039 REVISED JANUARY 26, 2016 - - Formatted: Font: (Default) +Body (Calibri), Bald Permitted surface or deep mining operations and projects, or oil and gas operations and projects conducted under the provisions of Title 45.1; Clearing of lands specifically for agricultural purposes and the management, tilling, planting, or harvesting of agricultural, horticultural, or forest crops, livestock feedlot operations, or as additionally set forth by the State Water Control Board in regulations, including engineering operations as follows: construction of terraces --terrace outlets, check dams, desilting basins, dikes, ponds, ditches, strip cropping, lister furrowing, contour cultivating, contour furrowing, land drainage, and land irrigation; however, this exception shall not apply to harvesting of forest crops unless the area on which harvesting occurs is reforested artificially or naturally in accordance with the provisions of Chapter 11 (§ 10.1-1100 et seq.) or is converted to bona fide agricultural or improved pasture use, as described in subsection B of § 10.1-1163 of Article 9 of Chapter 11 of Title 10.1 of the Code of Virginia; 3. Single-family residences separately built and disturbing less than one acre and not part of a larger common plan of development or sale, including additions or modifications to existing single-family residential structures; 4. Other land disturbing activities that disturb less than one acre of land area, except land disturbing activities that are part of a larger common plan of development or sale that is one acre or greater of disturbance; 5. Discharges to a sanitary sewer or a combined sewer system; 6. Activities under a state or federal reclamation program to return an abandoned property to an agricultural or open land use; 7. Routine maintenance that is performed to maintain the original line and grade, hydraulic capacity, or original construction of the project. The paving of an existing road with a compacted or impervious surface and reestablishment of existing associated ditches and shoulders shall be deemed routine maintenance performed in accordance with this subsection; and 8. Conducting land -disturbing activities in response to a public emergency where the related work requires immediate authorization to avoid imminent endangerment to human health or the environment. In such situations, the Administrator shall be advised of the disturbance within seven days of commencing the land -disturbing activity and compliance with the administrative requirements of subsection A is required within 30 days of commencing the land -disturbing activity. Page 6 of 274039 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bold D. previsie-n?,- ff this r el- shall Ret be o pliGable w Section 23-1.4 COMPATABILITY WITH OTHER REQUIREMENTS This ordinance is not intended to interfere with, abrogate, or annul any other ordinance, rule or regulation, stature, or other provision of law. The requirements of this ordinance should be considered minimum requirements, and where any provision of this ordinance imposes restrictions different from those imposed by any other ordinance, rule or regulation, or other provision of law, whichever provisions are more restrictive or impose higher protective standards for human health or the environment shall apply. Section 23-1.5 SEVERABILITY 40k, If the provisions of any article, section, subsection, paragraph, subdivision or clause of this ordinance shall be judged invalid by a court of competent jurisdiction, such order of judgment shall not affect or invalidate the remainder of any article, section, subsection, paragraph, subdivision or clause of this ordinance. Section 23-1.6 STORMWATER MANAGEMENT TECHNICAL CRITERIA FOR REGULATED LAND DISTURBING ACTIVITIES The County hereby adopts the technical criteria for regulated land -disturbing activities set forth in Part IIB of the Regulations, as amended, expressly to include 9VAC25-870- 62 [applicability]; 9VAC25-870-63 [water quality design criteria requirements]; 9VAC25- 870-65 [water quality compliance]; 9VAC25-870-66 [water quantity]; 9VAC25-870-69 [offsite compliance options]; 9VAC25-870-72 [design storms and hydrologic methods; 9VAC25-870-74 [stormwater harvesting]; 9VAC25-870-76 [linear development projects]; 9VAC25-870-85 [stormwater management impoundment structures or facilities]; and 9VAC25-870-92 [comprehensive stormwater management plans], which shall apply to all land disturbing activities regulated pursuant to this ordinance, except as expressly set forth in section 23-1.7 of this ordinance. Section 23-1.7 STORMWATER MANAGEMENT TECHNICAL CRITERIA FOR REGULATED LAND DISTURBING ACTIVITIES: GRANDFATHERED PROJECTS AND PROJECTS SUBJECT TO THE PROVISIONS OF 9VAC25-870-47B A. The County hereby adopts the technical criteria for regulated land -disturbing activities set forth in Part 11-C of the Regulations, as amended, expressly to include 9VAC25-870-93 [definitions]; 9VAC25-870-94 [applicability]; 9VAC25- 870-95 [general]; 9VAC25-870--96 [water quality]; 9VAC25-870-97 [stream channel erosion]; 9VAC25-870-98 [flooding]; and 9VAC25-870-99 [regional (watershed -wide) stormwater management plans], which shall only apply to all land disturbing activities regulated pursuant to this section. Page 7 of 274039 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald B. Any land -disturbing activity shall be considered grandfathered and shall be subject to the Part II C technical criteria of the Regulations, provided: A proffered or conditional zoning plan, zoning with a plan of development, preliminary or final subdivision plat, preliminary or final site plan, or any document determined by R o a n o k e C o u n ty t#t s to be Change requested by equivalent thereto (i) was approved by R o a n o k e C o u n ty+"--;eGa;i`� DEQ. prior to July 1, 2012, (ii) provided a layout as defined in 9VAC25-870- 10 and section 23-2, (iii) will comply with the Part II C technical criteria of the VSMP Regulation, and (iv) has not been subsequently modified or amended in a manner resulting in an increase in the amount of phosphorus leaving each point of discharge, and such that there is no increase in the volume or rate of runoff; A state permit has not been issued prior to July 1, 2014; and Land disturbance did not commence prior to July 1, 2014. C. County, state, and federal projects shall be considered grandfathered and shall be subject to the Part II C technical requirements of the Regulations, provided: There has been an obligation of county, state, or federal funding, in whole or in part, prior to July 1, 2012, or the Department has approved a stormwater management plan prior to July 1, 2012; A state permit has not been issued prior to July 1, 2014; and Land disturbance did not commence prior to July 1, 2014. D. Land disturbing activities grandfathered under subsections B and C of this section shall remain subject to the Part II C technical criteria of the Regulations for one additional state permit cycle. After such time, portions of the project not under construction shall become subject to the technical criteria in effect at that time. E. In cases where governmental bonding or public debt financing has been issued for a project prior to July 1, 2012, such project shall be subject to the technical requirements of the Part II C technical criteria of the Regulations. Land disturbing activities that obtain general permit coverage or commence land disturbance prior to July 1, 2014, shall be conducted in accordance with the Part II C technical criteria of the Regulations and Roanoke County's local stormwater management requirements that were in effect at the time of receiving general permit coverage or commencing land disturbance. Such projects shall remain subject to these requirements for an additional two general permit cycles, if general permit coverage is maintained. After that time, portions of the project, Page 8 of 274039 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald not under construction, shall become subject to the technical criteria in effect at that time. G. An operator may choose to decline grandfather status and to instead comply with the technical requirements of section 23-1.6 of this ordinance. Nothing in this section shall preclude an operator from constructing to a more stringent standard at his discretion. Section 23-1.8 STORMWATER MANAGEMENT DESIGN MANUAL A. The County will utilize the policies, criteria. and information contained within the County Stormwater Management Design Manual for proper implementation of the requirements of this ordinance. B. The County Stormwater Management Design Manual may be updated and revised from time to time. The Administrator shall recommend any updates, supplements, or modifications of the County Stormwater Management Design Manual subject to the authorization and approval by the Board of Supervisors by resolution. Section 23-1.9 COUNTY RIGHT OF ENTRY A. The Administrator and/or duly authorized employees, agents, or representatives of the County, bearing proper credentials and identification, may, at any reasonable times and under reasonable circumstance, enter any establishment or upon any property, public or private, which has a VSMP permit or a maintenance agreement, for the purpose of enforcing this ordinance, including, but not limited to: 1. Obtaining information or conducting surveys or investigations; 2. Taking samples of discharges; 3. Inspecting monitoring equipment; 4. Inspecting and copying documents relevant to the enforcement of this ordinance; 5. Initiating or maintaining appropriate actions which are required by the permit conditions associated with a land -disturbing activity when a permittee, after proper notice, has failed to take acceptable action within the time specified; 6. Inspecting stormwater management facilities or other Best Management Practices (BMPs1 or to initiate or maintain appropriate actions which are required to restore proper functioning of a —stormwater management facility or other BMP operation when a land Page 9 of 274039 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald owner, after proper notice, has failed to take acceptable action within the time specified; And such other items as may be deemed necessary for the enforcement of this ordinance. B. If the Administrator has cause to believe an activity regulated under this ordinance is occurring without a VSMP permit, or if the person in charge of the property refuses to allow the Administrator to enter in accordance with subsection A, then the Administrator may present sworn testimony to a magistrate or court of competent jurisdiction and request the issuance of an inspection warrant to enter the property for the purpose of making such inspection and investigation. The Administrator shall make a reasonable effort to obtain consent from the owner or person in charge of the property prior to seeking the issuance of an inspection warrant under this section. SECT I..N 23-2 DEFINITIONS 40 In addition to the definitions set forth in 9VAC25-870-10 of the Virginia Stormwater Management Regulations, as amended, which are expressly adopted and incorporated herein by reference, the following words and terms used in this ordinance have the following meanings, unless otherwise specified herein. Where definitions differ, those incorporated herein shall have precedence. "Administrator" means the VSMP authority responsible for administering the VSMP on behalf of the County of Roanoke. The Administrator shall be the Director of Community Development and any duly authorized agent of the Director of Community Development, or the person designated by the County Administrator to administer this ordinance on behalf of the County. "Agreement in lieu of a Stormwater Management Plan" means a contract between the VSMP authority and the owner or permittee that specifies methods that shall be implemented to comply with the requirements of a VSMP for the construction of a single-family residence; such contract may be executed by the VSMP authority in lieu of a stormwater management plan. "Applicant" means any person submitting an application for a permit or requesting issuance of a permit under this Ordinance. "Best Management Practice or BMP" means schedules of activities, prohibitions of practices, including both a -structural or nonstructural practices, maintenance procedures, and other management practices to prevent or reduce the pollution of surface waters and groundwater systems from the impacts of land -disturbing activities. Page 10 of 274039 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald "Clean Water Act or CWA" means the federal Clean Water Act (33 United States Code 1251 et seq.), formerly referred to as the Federal Water Pollution Control Act or Federal Water Pollution Control Act Amendments of 1972, Public Law 92-500, as amended by Public Law 95-217, Public Law 95-576, Public Law 96-483, and Public Law 97-117, or any subsequent revisions thereto. "Common plan of development or sale" means a contiguous area where separate and distinct construction activities may be taking place at different times on different schedules. "Control measure" means any best management practice or other method used to prevent or reduce the discharge of pollutants to tatesw#aeel waters_ - - Change requested by DEQ. "County" means the County of Roanoke, Virginia. "Department" means the Department of Environmental Quality. "Development" means land disturbance and the resulting landform associated with the construction of residential, commercial, industrial, institutional, recreation, transportation or utility facilities or structures, or the clearing of land for non-agricultural or non- silvicultural purposes. "Executed Development Agreements" means documents that are executed by the applicant and County that implements the various sureties. "Fee in lieu" means a payment of money to the County for the use of a regional stormwater management facility in place of meeting all or part of the stormwater performance standards required by this Ordinance on the site. "General permit" means the state permit titled GENERAL PERMIT FOR DISCHARGES OF STORMWATER FROM CONSTRUCTION ACTIVITIES found in Part XIV (9VAC25-880-1 et seq.) of the Regulations authorizing a category of discharges under the CWA and the Act within a geographical area of the Commonwealth of Virginia. "Illicit discharge" means any discharge to a municipal separate storm sewer that is not composed entirely of stormwater, except discharges pursuant to a VPDES or VSMP permit (other than the VSMP permit for discharges from the municipal separate storm sewer), discharges resulting from firefighting activities, and discharges identified by and in compliance with 9VAC25-870-400 D 2 c (3). "Land disturbance" or "Land -disturbing activity" means a manmade change to the land surface that potentially changes its runoff characteristics including any clearing, grading, or excavation, except that the term shall not include those exemptions specified in Section 23-1.3 of this Ordinance. Page 11 of 274039 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald "Layout" means a conceptual drawing sufficient to provide for the specified stormwater management facilities required at the time of approval. "Minor modification" means an amendment to an existing general permit before its expiration not requiring extensive review and evaluation including, but not limited to, changes in EPA promulgated test protocols, increasing monitoring frequency requirements, changes in sampling locations, and changes to compliance dates within the overall compliance schedules. A minor general permit modification or amendment does not substantially alter permit conditions, substantially increase or decrease the amount of surface water impacts, increase the size of the operation, or reduce the capacity of the facility to protect human health or the environment. "Municipal separate storm sewer" means a conveyance or system of conveyances otherwise known as a municipal separate storm sewer system or "MS4," including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man- made channels, or storm drains: 1. Owned or operated by Roanoke County; 2. Designed or used for collecting or conveying stormwater; 3. That is not a combined sewer; and 4. That is not part of a publicly owned treatment works. "Municipal separate storm sewer system" or "MS4" means all municipal separate storm sewers that are located within the portion of the County that is identified as "urbanized" by the U.S. Bureau of the Census in the latest Decennial Census. "Municipal Separate Storm Sewer Management Program" or "MS4 Program" means a management program covering the duration of a permit for a municipal separate storm sewer system that includes a comprehensive planning process that involves public participation and intergovernmental coordination, to reduce the discharge of pollutants to the maximum extent practicable, to protect water quality, and to satisfy the appropriate water quality requirements of the CWA and regulations and the Act and attendant regulations, using management practices, control techniques, and system design and engineering methods, and such other provisions that are appropriate. "Off-site facility" means a stormwater management measure located outside the subject property boundary described in the permit application for land -disturbing activity. "Operator" means the owner or operator of any facility or activity subject to regulation under this Ordinance. "Permit or VSMP Authority Permit" means an approval to conduct a land disturbing activity issued by the Administrator for the initiation of a land -disturbing activity, in accordance with this Ordinance, which may only be issued after evidence of general permit coverage has been provided by the Department. Page 12 of 274039 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald "Permittee" means the person to whom the VSMP Authority permit is issued "Person" means any individual, corporation, partnership, firm, association, joint venture, public or private or municipal corporation, trust, estate, commission, board, public or private institution, utility, cooperative, county, city, town or other political subdivision of the Commonwealth, any interstate or governmental body, or any other legal entity, or any agent or employee of any such person. "Regional stormwater management facility" or "Regional facility" means a facility or series of facilities designed to control some or all of the adverse impacts from stormwater runoff from two or more parcels or lots, located in the same watershed, although only portions of the area may experience development. "Regulations" means the Virginia Stormwater Management Program (VSMP) Ott Regulations, 9VAC25-870-10 et seq., as amended. "Site" means the land or water area where any facility or land -disturbing activity is physically located or conducted, including adjacent land used or preserved in connection with the facility or land -disturbing activity. ;. "State" means the Commonwealth of Virginia. "State Board" means the State Water Control Boar V "State Permit" means an approval to conduct` a land -disturbing activity issued by the State Board in the form of a state stormwater individual permit or coverage issued under a state general permit or an approval issued by the State Board for stormwater discharges from an MS4. Under these state permits, the Commonwealth imposes and enforces requirements pursuant to the federal Clean Water Act and regulations, the Virginia Stormwater Management Act and the Regulations. "State Water Control Law" means Chapter 3.1 (§62.1-44.2 et seq.) of Title 62.1 of the Code of Virginia (1950), as amended. "State waters" means all water, on the surface and under the ground, wholly or partially within or bordering the Commonwealth or within its jurisdiction, including wetlands. "Stormwater" means precipitation that is discharged across the land surface or through conveyances to one or more waterways and that may include stormwater runoff, snow melt runoff, and surface runoff and drainage. "Stormwater facility maintenance agreement" means a legally binding agreement between the owner of a property and the County regarding long-term maintenance of stormwater management facilities. Page 13 of 274039 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald "Stormwater Management Facility" or "SWMF" means a device that controls stormwater runoff and changes the characteristics of that runoff including, but not limited to, the volume, rate of flow, quality, the period of release, or the velocity of flow. "Stormwater management plan" means a document(s) containing material #er describing methods for complying with the requirements of Section 23-3.5 of this Ordinance. "Stormwater Pollution Prevention Plan" or "SWPPP" means a document that is prepared in accordance with good engineering practices and that identifies potential sources of pollutants that may reasonably be expected to affect the quality of stormwater discharges from the construction site, and otherwise meets the requirements of this Ordinance. In addition, the document shall identify and require the implementation of control measures, and shall include, but not be limited to. the inclusion of, or the incorporation by reference of, an approved erosion and sediment control plan, an approved stormwater management plan, and a pollution prevention plan. "Subdivision" means the division of a parcel of land into two (2) or more parcels of any size by the establishment of new he-ndaries boundary lines or by the adjustment, relocation, or vacation of existing boundary lines, for the purpose. whether immediate or future, of transfer of ownership or building development. A subdivision includes all changes in street or lot lines, and any portion of any such subdivision previously recorded in which building development or street creation occurs, or is required, subsequent to such recordation. The transfer of ownership of land to the Commonwealth of Virginia or a political subdivision thereof and the division of lands by court order or decree shall not be deemed a subdivision as otherwise herein defined. "Total Maximum Daily Load" or "TMDL" means the sum of the individual waste load allocations for point sources, load allocations for nonpoint sources, natural background loading and a margin of safety. TMDLs can be expressed in terms of either mass per time, toxicity, or other appropriate measures. The TMDL process provides for point versus nonpoint source trade-offs. "Town" means the incorporated Town of Vinton. "Virginia Stormwater Management Act" or "Act' means Article 2.3 (§ 62.1-44.15:24 et seq.) of Chapter3.1 of Title 62.1 of the Code of Virginia. "Virginia Stormwater BMP Clearinghouse website" means a website that contains detailed design standards and specifications for control measures that may be used in Virginia to comply with the requirements of the Virginia Stormwater Management Act and associated regulations. "Virginia Stormwater Management Program" or "VSMP" means a—the program approved by the State Board after September 13, 2011, that has been established by a Page 14 of 274039 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald aesaIOWRoanoke County to manage the quality and quantity of runoff resulting from land -disturbing activities and shall include such items as tesalCounty ordinances, rules, permit requirements, annual standards and specifications, policies and guidelines, technical materials, and requirements for plan review, inspection, and enforcement, where authorized in this Ordinance, and evaluation consistent with the requirements of this Ordinance and associated regulations. "Virginia Stormwater Management Program authority" or VSMP authority" means an authority approved by the State Board after September 13, 2011, to operate a Virginia Stormwater Management Program. For the purpose of this Ordinance, Roanoke County is the VSMP Authority for Roanoke County, including the Town of Vinton. SECTION 23 - PROGRAM PERMIT PROCEDURES AND REQUIREMENTS Section 23-3.1 PERMIT REQUIRED A. No grading, building, or other local permit will be issued for a property until a VSMP authority permit has been issued by the Administrator, unless the activity is specifically exempted from VSMP permitting by this Ordinance. B. No VSMP authority permit will be issued unless and until the permit application and attendant materials and supporting documentation demonstrate that all land clearing, construction, disturbance, land development and drainage will be done according to the requirements of this Ordinance, including an approved erosion and sediment control plan; and an approved stormwater management plan or an executed agreement in lieu of a stormwater management plan. C. No VSMP authority permit will be issued without the general permit registration statement except that construction activity involving a single-family detached residential structure, within or outside of a common plan of development or sale does not require a permit registration statement. Construction activities involving a single-family detached residential structure, within or outside of a common plan of development or sale, shall comply with the requirements of the General Permit. Section 23-3.2 PERMIT APPLICATION CONTENTS A. Unless specifically exempted by this Ordinance, any land—owner or operator desiring a permit for a land disturbance activity shall submit to the County a permit application on a form provided by the County for that purpose. Permit applications shall comply with the requirements contained within the County Stormwater Management Design Manual that is available from the Department of Community Development^fes Page 15 of 274039 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald B. No VSMP authority permit shall be issued by the Administrator, until the following items have been submitted to and approved by the Administrator as prescribed herein. 1. A permit application that includes a fully -executed general permit registration statement, except that construction activity involving a single- family detached residential structure, within or outside of a common plan of development or sale does not require a permit registration statement; 2. An erosion and sediment control plan approved in accordance with the County Erosion and Sediment Control Ordinance [Chapter 8.1]; 3. A stormwater management plan, or agreement in lieu of a stormwater management plan, that meets the requirements of Section 23-3.5; 4. Maintenance agreement in accordance with Section 23-3.7; 5. Performance bonds in accordance with Section 23-3.8; 6. Fees in accordance with Section 23-3.9; and, 7. Executed Development Agreements. x C. Pursuant to § 62.1-44.15:40 of the Code of Virginia, the Administrator may require every VSMP authority permit applicant or permittee, or any such person subject to VSMP authority permit requirements under this Ordinance, to furnish, when requested, such application materials, plans, specifications, and other pertinent information as may be necessary to determine the effect of the permittee's discharge on the quality of state waters, or such other information as may be necessary to accomplish the purposes of this Ordinance. Section 23-3.3 STORMWATER POLLUTION PREVENTION PLANS A. The Stormwater Pollution Prevention Plan (SWPPP) required by the general permit, shall comply with the requirements set forth in 9VAC25-870-54 and shall also comply with the requirements and general information set forth in Section 9VAC25-880-70, Section II [stormwater pollution prevention plan] of the general permit. The SWPPP shall include: 1. An approved erosion and sediment control plan; 2. An approved stormwater management plan, or agreement in lieu of a stormwater management plan; 3. A pollution prevention plan for regulated land disturbing activities; and 4. Description of any additional control measures necessary to address a TMDL. Page 16 of 274039 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald B. The SWPPP shall be amended, by the operator, whenever there is a change in design, construction, operation, or maintenance that has a significant effect on the discharge of pollutants to state waters, which is not addressed by the existing SWPPP. C. The SWPPP shall be maintained at a central location onsite. If an onsite location is unavailable, notice of the SWPPP's location must be posted near the main entrance at the construction site. Operators shall make the SWPPP available for public and County review in accordance with Section II of the general permit, either electronically or in hard copy. Section 23-3.4 POLLUTION PREVENTION PLANS' A. A Pollution Prevention Plan, required by 9VAC25-870-56, shall be developed, implemented, and updated as necessary and must detail the design, installation, implementation, and maintenance of effective pollution prevention measures to minimize the discharge of pollutants. B. At a minimum, such measures must be designed, installed, implemented, and maintained to: 1. Minimize the discharge of pollutants from equipment and vehicle washing, wheel wash water, and other wash waters. Wash waters must be treated in a sediment basin or alternative control that provides equivalent or better treatment prior to discharge; 2. Minimize the exposure of all materials, including, but not limited to building materials, building products, construction wastes, trash, landscape materials, fertilizers, pesticides, herbicides, detergents, sanitary waste, and other materials present on the site to precipitation and to stormwater; and Minimize the discharge of pollutants from spills and leaks and implement chemical spill and leak prevention and response procedures. C. The pollution prevention plan shall include effective best management practices torop hibit the following discharges: 1. Wastewater from washout of concrete, unless managed by an appropriate control; 2. Wastewater from washout and cleanout of stucco, paint, form release oils, curing compounds, and other construction materials; 3. Fuels, oils, or other pollutants used in vehicle and equipment operation and maintenance; and 4. Soaps or solvents used in vehicle and equipment washing. Page 17 of 274039 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald D. The pollution prevention plan shall prohibit discharges from dewatering activities, including discharges from dewatering of trenches and excavations, unless managed by appropriate controls. Section 23-3.5 STORMWATER MANAGEMENT PLANS A. No application for land -disturbing activity will be approved unless it includes a stormwater management plan or agreement in lieu of a stormwater management plan, as required by this Ordinance, detailing how runoff and associated water quality impacts resulting from the activity will be controlled or managed. B. Submittal, review, approval, and resubmittal of stormwater management plans, and agreements in lieu of stormwater management plans shall comply with the requirements set forth in this Ordinance and the County Stormwater Management Design Manual. C. The stormwater management plan shall apply the stormwater management technical criteria set forth in Section 23-1.6 of this Ordinance to the entire common plan of development or salela-Fid- ar.: ;PNORg- amity. Individual lots in new residential, commercial, or industrial developments, including those developed by subsequent owners, shall not be considered to be separate land - disturbing activities�. - - Revisions requested by DEQ. D. A stormwater management plan that is approved for a residential, commercial, or industrial subdivision shall govern the development of the individual parcels, including those parcels developed under subsequent owners E. The stormwater management plan must consider all sources of surface runoff and all sources of subsurface and groundwater flows converted to surface runoff. F. If an operator intends to meet the water quality and/or quantity requirements set forth in 9VAC25-870-63 or 9VAC25-870-66 through the use of off-site compliance options, where applicable, then a letter of availability from the off-site provider must be included. Approved off-site options must achieve the necessary nutrient reductions prior to the commencement of the applicant's land -disturbing activity except as otherwise allowed by §62.1-44.15:35 of the Code of Virginia. G. Elements of the stormwater management plans that include activities regulated under Chapter 4 (§54.1-400 et seq.) of Title 54.1 of the Code of Virginia shall be appropriately sealed and signed by a professional registered in the Commonwealth of Virginia pursuant to Article 1 (§ 54.1-400 et seq.) of Chapter 4 of Title 54.1 of the Code of Virginia. H. Where a stormwater management plan is required, a construction record drawing for permanent stormwater management facilities shall be submitted to the Administrator and approved prior to the release of bonds. The construction record drawing shall be appropriately sealed and signed by a professional Page 18 of 274039 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald registered in the Commonwealth, certifying that the stormwater management Page 19 of 274039 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald facilities have been constructed in compliance with the approved plan. Stormwater management facilities include all storm drain structures, storm drain pipes, culverts, open channels, BMPs, and all other facilities used to convey, control, or treat stormwater runoff. The stormwater management plan shall include the following information: 1. Information on the type and location of stormwater discharges; information on the features to which stormwater is being discharged including surface waters or karst features, if present, and the pre -development and post - development drainage areas; 2. Contact information including the name, address, and telephone number of the owner and the tax reference number and parcel number of the property or properties affected; 3. A narrative that includes a description of current site conditions and final site conditions or if allowed by Roanoke County, the information provided and documented during the review process that addresses the current and final site Icondltlons; - Revisions requested by DEQ. 4. A general description of the proposed stormwater management facilities and the mechanism through which the facilities will be operated and maintained after construction is complete; 5. Information on the proposed stormwater management facilities, including: (i) The type of facilities; (ii) Location, including geographic coordinates; (iii) Acres treated; and (iv) Surface area, volume, depth, and width of facilities, if applicable; (v) The surface waters or karst features, if present, into which the facility will discharge ;and (vi) The Hydrologic Unit Code (HUC) into which the facilities drain. 6. Hydrologic and hydraulic computations, including runoff characteristics; 7. Documentation and calculations verifying compliance with the water quality and quantity requirements of the regulationsl - - Revision requested by DEQ. 8. A map or maps of the site that depicts the topography of the site and includes: (i) All contributing drainage areas; (ii) Existing streams, ponds, culverts, ditches, wetlands, other water bodies, and floodplains; (iii) Soil types, geologic formations if karst features are present in the Page 49-Gf-39 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bold area, forest cover, and other vegetative areas; (iv) Current land use, including existing structures, roads, and locations of known utilities and easements; (v) Sufficient information (such as grades, structures and pavements, and other appropriate information) on adjoining parcels to assess the impacts of stormwater from the site on these parcels; (vi) The limits of clearing and grading, and the proposed drainage patterns on the site; (vii) Proposed buildings, roads, parking areas, utilities, and stormwater management facilities; and (viii) Proposed land use with tabulation of the percentage of surface area to be adapted to various uses, including but not limited to planned locations of utilities, roads, and easements. An agreement in lieu of stormwater management plan shall conform to the Regulations and the County Stormwater Management Design Manual. Section 23-3.6 COMPREHENSIVE STORMWATER MANAGEMENT PLANS AND REGIONAL STORMWATER MANAGEMENT FACILITIES A. The County may develop comprehensive stormwater management plans in accordance with 9VAC25-870-92 as a means to more effectively and efficiently address water quality objectives, quantity objectives, or both; through the implementation of regional stormwater management facilities. B. Once a comprehensive stormwater management plan is adopted by the County and approved by the Director of the Virginia Department of Environmental Quality, it is enforceable under this Ordinance. C. Stormwater management plans for land disturbing activities located in areas that have a comprehensive stormwater management plan, adopted by the County, and approved by the Director of the Virginia Department of Environmental Quality, shall comply with the requirements of the comprehensive stormwater management plan. If a proposed regulated land -disturbing activity is located in a watershed that has a regional stormwater management facility currently constructed, and if the regional stormwater management facility is in accordance with a comprehensive stormwater management plan, the County shall have the option to require the payment of a fee -in -lieu of providing a portion or all of the proposed regulated land -disturbing activities stormwater management requirements. The fee -in -lieu shall be based on the reasonable proportion of stormwater impacts from the proposed regulated land -disturbing activity compared to the total stormwater impacts that the regional stormwater management facility is designed to mitigate, multiplied by the total estimated project costs. The reasonable proportion of project costs shall be solely determined by the County. Project costs include, but are not limited to, the costs of land, professional services for investigations, REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald studies, design, environmental permitting, surveying, construction phase REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald services, legal services, and construction. Project costs may also include County staff costs for project development, design, construction, permitting, oversight, or other project activities; and other direct costs. Project costs shall also include the present value of the estimated operation and maintenance costs for the next 20_years, if the County is responsible for the regional stormwater management facility's operation and maintenance. D. The County and any other party (ies) may mutually agree to share the costs of a regional stormwater management facility, in the absence of a comprehensive stormwater management plan. The fee -in -lieu shall be based on project costs apportioned to each party in reasonable proportion of each party's contribution to the total stormwater impacts that the regional stormwater management facility is designed to mitigate, as mutually negotiated. Section 23-3.7 STORMWATER MANAGEMENT FACILITY MAINTENANCE AGREEMENTS A. Maintenance of a4-stormwater management facilities shall be ensured through the creation of a formal maintenance agreement that is executed by the property owner and submitted prior to plan approval and recorded by the County in the County land records prior to permit termination. The maintenance agreement shall be binding on all subsequent property owners. B. The property owner of the site shall execute an access easement agreement, prior to plan approval, to provide for access to stormwater management facilities at reasonable times for periodic inspection by the County, or their contractor or agent, to ensure that the facility is maintained in proper working condition to meet design standards and any other provisions established by this Ordinance. The easement agreement shall be recorded in the County land records by the County and it shall be binding on all subsequent property owners. C. A stormwater management facility that serves more than one parcel shall be located on its own, separate parcel. The land owners of each parcel served by the stormwater management facility shall be jointly and severally responsible for the maintenance of the stormwater management facility through a formal maintenance agreement with the County. D. Responsibility for the operation and maintenance of stormwater management facilities, unless assumed by a governmental agency, shall remain with the property owner and shall pass to any successor or owner. If portions of the land are to be sold, legally binding arrangements, acceptable to the County, shall be made to pass the responsibility to successors in title. These arrangements shall designate for each land owner, governmental agency, or other legally established entity to be permanently responsible for maintenance. REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald E. As part of the maintenance agreement, a schedule shall be developed identifying anticipated routine maintenance, to be performed by the property owner, needed for proper function of the stormwater management facility. The maintenance agreement shall also include a schedule for periodic inspections, to be performed by the property owner, to ensure proper performance of the facility between scheduled routine maintenance activities, and it shall require repairs when needed for proper function of the SWMF. The maintenance agreement shall require that the property owner document routine maintenance, repair, and periodic inspection activities, maintain said documentation for five (5)_years, and submit said documentation to the County, if requested. The maintenance agreement shall also include "failure to maintain" provisions. In the event that maintenance or repair is neglected, or the stormwater management facility becomes a danger to public health, safety, or the environment, the County reserves the authority to perform the necessary maintenance or repair work and to recover the costs from the property owner. Nothing in this Ordinance shall be construed to mean that the County has the responsibility to maintain privately -owned SWMFs. G. Prior to the release of the performance security or bond, the developer shall either (1) transfer the maintenance responsibilities of the stormwater management facilities to a Home Owners Association or (2) provide the County with a maintenance security. - 1. Requirements for Transfer of Maintenance Responsibilities to the Home Owners Association (HOA) i. Submission of acceptable record drawings. ii. Acceptable final inspection of the stormwater management facility by the County. iii. Transfer of the necessary property to the HOA. iv. Organize and hold a meeting attended by the developer, the County and members of the HOA. Provide evidence to the County that each member of the HOA was provided prior notice of the meeting. The meeting shall be held at a place and time convenient for members of the HOA. v. Provide a copy of the recorded documents establishing the Home Owners Association to the County. vi. Provide the County with evidence that the Home Owners Association is funded. Minimum funding shall be based on the following schedule: 1-20 lots = $1,000 21-50 lots = $1,500 51 and over = $1500 + $30 per lot over 50 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bold 2. Requirements for Posting Maintenance Security. i. The County shall require a maintenance guaranty in the amount of twenty (20%) percent of the construction costs of the stormwater management facility. ii. The maintenance security shall contain forfeiture provisions for failure, after proper notice, to complete work within the time specified, or to initiate or maintain appropriate actions which may be required of the permittee in accordance with the approved stormwater management plan. iii. If the County takes such action upon such failure by the permittee, the County may collect from the permittee the difference should the amount of the reasonable cost of such action exceed the amount of the security held. iv. The maintenance agreement and security will be the responsibility of the permittee or owner until such time as the permittee or owner provides the County with the necessary requirements for Transfer of Maintenance Responsibilities to the Home Owners Association as outlined above in (1). At the discretion of the Administrator, a formal maintenance agreement and Required to addressnse -------------------------------------------------------------- access easement agreement mayee94 not be required for stormwater ofagreementsinlieu ofSWMPlans for single management facilities designed to treat stormwater runoff primarily from an familyresidential construction. individual single-family residential lot on which they are located, provided it is demonstrated to the satisfaction of the Administrator that future maintenance of such facilities will be addressed through an enforceable mechanism at the discretion of the Administra4eeRor. If a formal maintenance aareement and access easement aareement is not required as described in paragraph H above, the Administrator shall develop a strategy for addressinq maintenance of stormwater management facilities designed to treat stormwater runoff primarily from an individual single-family residential lot on which they are located. Such a strategy may include periodic inspections, homeowner outreach and education, or other method targeted at promoting the long-term maintenance of such facilities. Such facilities shall not be subiect to the reauirement for an inspection to be conducted by the Arlministratnr Section 23-3.8 PERFORMANCE SECURITIES A. The County may, at its discretion, require the submittal of a performance security or bond with surety, cash escrow, letter of credit, or other acceptable legal arrangement, all of which shall be in a form approved by the County, prior to plan approval, in order to ensure that the stormwater practices are installed by the permittee, as required by the approved stormwater management plan. B. h; W J64„ 1, _zs4:7-,4The amount of_the performance security shall be -the _--- Revisedtomatcnbond contingency amount in ESC Ordinance. Rage ^��39 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bold total estimated construction cost of the storm drainage systems and stormwater management facilities approved under the permit, plus 10% contingency. A## r julyi , 2917 the o n+ of +h8 peFfe "rm-r'anA-e ses'm'rity-shall -,tee-thrretetE;r@S�iii�a ied nnnc+n in+inn nr.o+ r.f the c+r.rm AFRI O.Rag@ c io+omo a.nrl c+r.rm�n48+8r m on+ s; appFeved 61RG18F8 198FMit, plus 25,4--veRtmtJ 4Y. GGRtiRg@RGY io iR r,rrlanneo.ithTitle 45_, Chapter 22, Ar+inle 41 (§ 1F2_224 et seq.) Af+ho GAGIo Af V'Fginio (1959) as 8FIG18d C. The performance security shall contain forfeiture provisions for failure, after proper notice, to complete work within the time specified, or to initiate or maintain appropriate actions which may be required of the permittee in accordance with the approved stormwater management plan. D. If the County takes such action upon such failure by the permittee, the County may collect from the permittee the difference should the amount of the reasonable cost of such action exceed the amount of the security held. E. Within 60 days of the completion of the requirements of the permit conditions, including request for permit termination by the operator, such bond, cash escrow, letter of credit, or other legal arrangement, or the unexpended or unobligated portion thereof, will be refunded to the permittee or terminated. Section 23-3.9 FEES A. Fees to cover costs associated with implementation of a VSMP related to land disturbing activities and issuance of general permit coverage and VSMP authority permits shall be imposed in accordance with the appropriate fee schedule established, updated and revised from time to time by the County Board of Supervisors by resolution. VSMP costs include County costs associated with stormwater management plan review, VSMP registration statement review, permit issuance, state -coverage verification, inspections, reporting, and compliance activities associated with land -disturbing activities, as well as state program oversight costs. B. Fees for providing coverage under the General Permit for Discharges of Stormwater from Construction Activities shall be imposed in accordance with the appropriate fee schedule established, updated and revised from time to time by the County Board of Supervisors by resolution. Fifty percent (50%) of the total fee shall be paid by the applicant at the time that a stormwater management plan, or agreement in lieu of a stormwater management plan, is submitted for review. The remaining total fee is to be paid by the applicant prior to issuance of coverage under the General Permit for Discharges of Stormwater from Construction Activities. C. When a site or sites has been purchased for development within a previously permitted common plan of development or sale, the applicant shall be subject to fees in accordance with the disturbed acreage of their site or sites according to REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald the fee schedule established, revised and updated from time to time by the County Board of Supervisors by resolution. D. Fees for the modification or transfer of registration statements from the general permit issued by the State Board shall be imposed in accordance with the fee schedule established, revised and updated from time to time by the County Board of Supervisors by resolution. If the permit modifications result in changes to stormwater management plans that require additional review by the County, such reviews shall be subject to the fee schedule established by the County Board of Supervisors, as amended. The fee assessed shall be based on the total disturbed acreage of the site. In addition to the general permit modification fee, modifications resulting in an increase in total disturbed acreage shall pay the difference in the initial permit fee paid and the permit fee that would have applied for the total disturbed acreage in accordance with the fee schedule established, revised and updated from time to time by the County Board of Supervisors by resolution. E. General permit maintenance fees: Annual permit maintenance fees required by 9VAC25-870-830 shall be imposed in accordance with the fee schedule established, revised and updated from time to time by the County Board of Supervisors by resolution, including fees imposed on expired general permits that have been administratively continued. With respect to the general permit, these fees shall apply until the permit coverage is terminated. General permit coverage maintenance fees, for permits issued in a previous calendar year, shall be paid by April 1st of each year that it is in effect. No permit will be reissued or automatically continued without payment of the required fee. General permit coverage maintenance fees shall be applied until a Notice of Termination is effective. F. Persons whose coverage under the general permit has been revoked shall apply to the V i ra in i a Department of Environmental Quality for an Individual Permit for Discharges of Stormwater from Construction Activities. G. No permit application fees will be assessed to: 1) Permittees who request minor modifications to permits as defined in Section 23-2 of this Ordinance. Permit modifications at the request of the permittee resulting in changes to stormwater management plans that require additional review by the Administrator shall not be exempt pursuant to this section. 2) Permittees whose permits are modified or amended at the initiative of the Department or Administrator, excluding errors in the registration statement identified by the Administrator or errors related to the acreage of the site. H. All incomplete payments will be deemed as nonpayments, and the applicant shall be notified of any incomplete payments. Interest may be charged for late payments at the underpayment rate set forth in §58.1-15 of the Code of Virginia and is calculated on a monthly basis at the applicable periodic rate. A 10% late Page 49-Gf-39 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald payment fee shall be charged to any delinquent (over 90 days past due) account. The County shall be entitled to all remedies available under the Code of Virginia in collecting any past due amount. I. In addition to the fees contained on the fee schedule established, revised and updated by the County Board of Supervisors by resolution the County may collect convenience fees associated with processing credit card payments. Section 23-3.10 PERMIT APPLICATION PROCEDURE A. Permit applications and the stormwater management plan, or agreement in lieu of a stormwater management plan, shall include all of the information required by this Ordinance and the County Stormwater Management Design Manual. B. No VSMP authority permit shall be issued until the maintenance agreement required in section 23-3.7 is approved, performance securities required in section 23-3.8 have been submitted and accepted, and fees required to be paid, pursuant to section 23-3.9, are received. C. All applications will be processed in accordance with procedures set forth below and in the County Stormwater Management Design Manual. 1. The Administrator shall determine the completeness of a plan in accordance with section 23-3.2 of this Ordinance and shall notify the applicant, in writing, of such determination, within 15 calendar days of receipt. If the plan is deemed to be incomplete, the above written notification will contain the reasons the plan is deemed incomplete. 2. The Administrator shall have an additional 60 calendar days from the date of the communication of completeness to review the plan, except that if a determination of completeness is not made within the time prescribed above, then plan shall be deemed complete and the Administrator shall have 60 calendar days from the date of submission to review the plan. 3. The Administrator shall review any plan that has been previously disapproved, within 45 calendar days of the date of resubmission. 4. During the review period, the plan shall be approved or disapproved and the decision communicated in writing to the applicant or his/her designated agent. If the plan is not approved, the reasons for not approving the plan shall be provided in writing. Approval or denial shall be based on the plan's compliance with the requirements of this Ordinance. 5. If a plan meeting all requirements of this Ordinance is submitted and no action is taken within the time provided above, the plan shall be deemed approved. REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald D. Approved stormwater management plans may be modified, as follows: 1. Modification to an approved stormwater management plan shall be allowed only after review and written approval by the Administrator. The Administrator shall have 60 calendar days to respond in writing either approving or disapproving such request. The Administrator may require that an approved stormwater management plan be amended, within a time prescribed by the Administrator, to address any deficiencies noted during inspection. E. The Administrator shall require the submission of a construction record drawing for permanent stormwater management facilities.', ,__,. SECTION 23-4 EXCEPTIONS TO STORMWATER MANAGEMENT REQUIREMENTS A. The Administrator may grant exceptions to the technical requirements of Part II B or Part II C of the Regulations, provided that (i) the exception is the minimum necessary to afford relief, (ii) reasonable and appropriate conditions are imposed so that the intent of the Act and this Ordinance are preserved, (iii) granting the exception will not confer any special privileges that are denied in other similar circumstances, and (iv) exception requests are not based upon conditions or circumstances that are self-imposed or self-created. Economic hardship alone is not sufficient reason to grant an exception from the requirements of this Ordinance. 1. Exceptions to the requirement that the land -disturbing activity obtain the required VSMP authority permit shall not be given by the Administrator, nor shall the Administrator approve the use of a BMP not found on the Virginia Stormwater BMP Clearinghouse Website, unless it is duly approved by the De artment D*esto of Environmental Quality_ - - CorreetionperDEQ request. 2. Exceptions to requirements for phosphorus reductions shall not be allowed unless offsite options otherwise permitted pursuant to 9VAC25- 870-69 have been considered and found not available. 3. Nothing in this section shall preclude an operator from constructing to a more stringent standard at their discretion. B. The Administrator may grant an exception from provisions contained in the County Stormwater Management Design Manual when not reasonably achievable, provided that acceptable mitigation measures are provided. C. Requests for an exception to the stormwater technical requirements shall be submitted in writing to the Administrator. REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald SECTION 23-5 PROPERTY OWNER RESPONSIBILITIES FOR DRAINAGE WAYS A. Drainage ways consist of natural watercourses, storm sewers, gutters, manmade channels, and other natural or manmade drainage paths. B. Every person owning property through which a drainage way passes, or such person's lessee, shall keep and maintain that part of the drainage way within the property free of trash, debris, yard wastes, and other obstacles that could pollute, contaminate, or significantly retard the flow of water. C. No person shall sweep, wash, or otherwise place dirt, trash, debris, yard wastes, or other materials in drainage ways where they could be picked up and carried off the person's property by stormwater runoff. D. The property owner or such person's lessee shall maintain healthy vegetation to protect the drainage way from excessive erosion during storm events. Particular care shall be taken to maintain healthy bank vegetation along watercourses. SECTION 23-6 CONSTRUCTION INSPECTION Section 23-6.1 NOTICE OF CONSTRUCTION COMMENCEMENT The permittee shall notify the County in advance before the commencement of land disturbing activities. In addition, the permittee shall notify the County in advance of construction of critical components of a stormwater management facility. Section 23-6.2 PERIODIC CONSTRUCTION INSPECTION A. The Administrator shall periodically inspect the land -disturbing activity during construction for: 1. Compliance with the approved erosion and sediment control plan; 2. Compliance with the approved stormwater management plan, or executed agreement in lieu of a stormwater management plan; 3. Development, updating, implementation with the pollution prevention plan; 4. Development and implementation of any additional control measures necessary to address a TMDL. B. If the County inspections find any violations, the permittee shall be notified in writing of the nature of the violation and the required corrective actions. No additional construction or land -disturbing activity in the area of the violation shall Page 49-Gf-39 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald proceed until any violations are corrected and all work previously completed has received approval from the County. The permittee is responsible f o r maintenance and repair for all stormwater management facilities during construction. C. The person responsible for implementing the approved plan is required to provide adequate inspection monitoring and reports to ensure compliance with the approved plan, to determine whether the measures required in the plan provide effective stormwater management and to allow the registered professional to certify the record documents in accordance with Section 23-3.5. All permittee inspections shall be documented and written reports prepared that contain the following information: 1. The date and location of the permittee inspection; 2. Whether construction is in compliance with the approved stormwater management plan; 2. Variations from the approved construction specifications; 3. Corrective actions that have been taken to correct previous violations; 4. Any violations that exist; an . 5. The name and signature of the person who performed the inspection. Permittee inspection documentation shall be organized chronologically and be stored with the SWPPP. D. If the County determines that there is a failure to comply with the plan, notice shall be served upon the permittee or person responsible for carrying out the plan in accordance with Section 23-9 of this Ordinance. Section 23-6.3 FINAL INSPECTION AND RECORD DOCUMENTATION A. The permittee shall submit record drawings and supporting documentation for all stormwater management facilitiesy and storm drainage systems associated with the project before final County inspection. Record drawings and supporting documents shall comply with the requirements contained in the County Stormwater Management Design Manual. Record drawings shall not be required where the Administrator does not require a formal maintenance agreement and access easement agreement for stormwater management facilities designed to treat stormwater runoff primarily from an individual single-family residential lot on which they are located. - Coordinated With special requirements for individual residential B. Receipt of record drawings and supporting documentation, final inspection and lot conditions. approval by the County, execution and recordation of maintenance agreement, Page 49-Gf-39 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bold and permit termination is required before the final release of performance securities. C. If it is determined from the record drawings, or inspections, that the storm drainage systems and the stormwater management facilities have not been constructed in accordance with the approved stormwater management plan, then corrective action will be taken to comply with the approved Plan or the permittee shall provide studies and information required by the County to demonstrate that the constructed system will function equivalent to the approved Stormwater Management Plan, and that all regulatory requirements are met. D. A suDDlemental diaital file of the record drawinas shall be submitted to the County for its use in maintaining public records. The supplemental digital file shall comply with the requirements contained in the Roanoke County Stormwater Management Design IManuall. - we need this information to aid in staff efficiency with maintaining GIS system. SECTION 23-7 POST CONSTRUCTION INSPECTION, MAINTENANCE AND REPAIR OF STORMWATER MANAGEMENT FACILITES Section 23-7.1 MAINTENANCE INSPECTIONS OF STORMWATER MANAGEMENT FACILITIES " A. Following the completion and acceptance of construction, the property owner is responsible for the maintenance and repair of stormwater structures and stormwater management facilities. The property owner shall ensure that proper maintenance and repair of stormwater structures and stormwater management facilities occur and that periodic inspection, maintenance, and repair are performed so that the structures and facilities operate properly. All inspection, maintenance, and repair activities, performed by the property owner shall be documented. Documentation shall be submitted to the County, if requested. B. Stormwater structures and stormwater management facilities that have recorded stormwater facility maintenance agreements shall be operated, inspected, maintained and repaired, by the property owner, in conformance with the applicable performance requirements contained in the approved stormwater facility maintenance agreement. C. LE*im&-Stormwater-structures -and stormwater m_anagement_facilities were added language to required as a condition for parcel development. Therefore, they shall be make clear that SWM facilities without operated, inspected, maintained and repaired, by the property owner, as agreements still require maintenance under ths ordinance. necessary for proper operation of the structures and facilities even if there is no+hat dr, net have Fero recordf4ed stormwater facility maintenance agreement shall be eperated inS198Gt8d maintained and repaired, by the +ieR f the +r��At ire and fa Amli+ies �er�s--requF er�eFa�sz��. In the event of non-compliance, the County at its discretion, after giving Page 49 -^mfr -39 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald aDDrODrlate notice to the DrODerty Owner may enter the DrODerty for the DurDOse Of maintaining or repairing stormwater management facilities. In the event that the County maintains or repairs stormwater management facilities, the cost and expense thereof shall be assessed against the property owner. —Following are the minimum maintenance requirements for stormwater structures and stormwater management facilities that do not have a recorded stormwater facility maintenance agreement: 1. Stormwater structures and stormwater management facilities shall be inspected and maintained or repaired as needed, by the property owner, after significant rainfall events that cause localized flooding, and at least annually. 2. All structures and slopes shall be kept in a safe condition. Stormwater sheet flow shall not be converted to concentrated flow by extending downspouts or other drains toward streets or property lines. Rain gardens, pervious pavement, and other stormwater management facilities shall not be removed or rendered inoperable. 3. Thp ;Stormwater management facilitiesy and stormwater conveyance systems shall be kept clear of grass clippings, cut brush, and other debris. 4. All pipes and structures shall be kept clean and clear of debris that could decrease flow capacity. 5. Sediment and silt that washes into stormwater management facilities shall be removed and properly disposed of when the sediment and silt builds up to the point that they adversely impact the facility's proper operation. 6. Trees and other woody plants shall be cut and removed from embankment slopes annually. 7. Trees and woody plants shall be cut and removed from non -embankment areas of a stormwater management facility as needed to avoid buildup of debris in the facility and to avoid a nuisance. Periodic cutting and brush removal shall occur at a frequency of at least once in three years. 8. Landscaping and grass cover shall be maintained for proper operation and erosion control. Replace landscaping as required. Repair erosion and replace grass cover as required. 9. Manufactured stormwater management facilities shall be maintained as recommended by the manufacturer. 8-10. Additional maintenance activities shall be performed, as needed, to maintain proper operation. D. In addition to the inspections performed by the property owner, the County will Page 49-G-39 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald periodically inspect stormwater management facilities. In the event that the stormwater management facility has not been maintained and/or becomes a danger to public safety, public health, or the environment, the County shall notify the property owner by registered or certified mail. The notice shall specify the measures needed to comply and shall specify the time within which such measures shall be completed. If the responsible party fails or refuses to correct the violation, the County, after reasonable notice, may correct a violation of the design standards or maintenance needs by performing all necessary work to place the facility in proper working condition, and recover the costs from the property owner. E. If stormwater management facility inspection requires entry into a confined space, or special equipment or training, then the County may hire licensed professionals to perform the inspection, or it may require the property owner to hire a licensed professional to perform the inspection. The cost for any licensed professionals to perform the required inspection shall be paid by or recovered from the owner. F. The County will conduct post -construction inspections of stormwater management facilities pursuant to the County's developed, and State Board's approved inspection program and will inspect each stormwater management facility at least once every five (5) years; except that periodic post -construction inspection, by the County, is not required where- a formal maintenance agreement and access easement agreement is not required by the Administrator for stormwater management facilities designed to treat stormwater runoff Primarily from an individual single-family residential lot on which they arelocated. - - Coordinated special requirement for individual single family Section 23-7.2 RECORDS OF INSPECTION, MAINTENANCE AND REPAIR development. A. Property owners responsible for the operation and maintenance of stormwater management facilities shall make records of all inspections, maintenance, and repairs, and shall retain the records for at least five (5) years. B. Upon request from the County, property owners shall provide copies of records documenting property owner inspections, maintenance, and repairs. SECTION 23-8 HEARINGS AND APPEALS Section 23-8.1 HEARINGS A. Any permit applicant or permittee, or person subject to the requirements of this Ordinance, who is aggrieved by any action, of the County in approving or disapproving any plans required by this Ordinance, or by any enforcement action taken pursuant to Sec. 23-9, shall have the right to request, in writing, a hearing, to+�„t-9 Ge6lFlty ° ristrate-F A -F 1406 heF desigF188 provided, that a petition requesting such hearing is filed with the Administrator within 30 days after REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bold notice of such action is given by the Administrator. t- - - J Formatted: Indent: Left: 0.58", No bullets A-. B. The hearing shall be heard by the County Administrator, or his/her designee. or numbering -&-.C. The hearing shall be held provided that the County Administrator and the aggrieved party has at least thirty (30) days prior notice. 4'—.D. A verbatim record of the proceedings of such hearings shall be taken and filed with the Board of Supervisors. Depositions may be taken and read as in actions at law. Q-. E. The County Administrator, shall have power to issue subpoenas and subpoenas duces tecum, and at the request of any party shall issue such subpoenas. The failure of any witness without legal excuse to appear or to testify or to produce documents shall be acted upon by the County Administrator whose actions may include the procurement of an order of enforcement from the circuit court. Witnesses who are subpoenaed shall receive the same fees and reimbursement for mileage as in civil actions. F. During its review, the County Administrator shall consider evidence presented by all parties. After considering the evidence, the County Administrator's decision shall be final. Section 23-8.2 APPEALS Final decisions of the County Administrat'&,"'ur der this Ordinance, shall be subject to judicial review by the Roanoke County Circuit Court, provided an appeal is filed within thirty (30) days from the date of any written decision adversely affecting the rights, duties, or privileges of any permit applicant, permittee, or person subject to any enforcement action under this Ordinance. SECTION 23-9 ENFORCEMENT AND PENALTIES Section 23-9.1 VIOLATIONS Any land -disturbance activity that is commenced or is conducted contrary to this Ordinance or the approved plans or agreements and permit, may be subject to the enforcement actions outlined in this section and the Virginia Stormwater Management Act. Section 23-9.2 NOTICE TO COMPLYOF tenni ATIQN - - Revised terminology to better coordinate with E&SC Ordinance A. If the Administrator determines that there is a failure to comply with the VSMP authority permit conditions, notice shall be served upon the permittee or person responsible for carrying out the permit conditions by any of the following: verbal warnings and inspection reports, notices of corrective action, consent special Page 49-Gf-39 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bold orders, and notices to comply. B. Written notices shall be served by registered or certified mail to the address specified in the permit application or by delivery at the site of the development activities to the agent or employee supervising such activities. C. If there is no permittee, the notices shall be issued to the property owner. D. The N+4otice to Complye�+eiat shall contain: 1. The name and address of the permittee, or if there is no permittee, the property owner; 2. The address when available or a description of the building, structure, or land upon which the violation is occurring; 11S�6' 3. A statement specifying the nature of the violation; 4. A description of the, Felm. 8d;E;1, remedial +1ese6s�measures necessary oto bring the. Iaxdthe land - disturbing activity into compliance with this Ordinance and a time schedule for the completion of such remedial action_ E. Upon failure to comply within the specified time, the permit may be revoked and the permittee shall be deemed to be in violation of this chapter and, upon conviction, shall be subject to the penalties provided by this chapter.; Section 23-9.3 STOP WORK ORDERS A. If a permittee fails to comply with a notice issued in accordance with Section 23- 9.2 within the time specified, the Administrator may issue an order requiring the owner, permittee, person responsible for carrying out an approved plan, or the person conducting the land -disturbing activities without an approved plan or required permit to cease all construction land -disturbing activities until the violation of the permit has ceased, or an approved plan and required permits are obtained, and specified corrective measures have been completed. Such Stop Work Orders shall become effective upon service on the person by certified mail. return receipt reauested. sent to the address specified in the land records of the locality, or by personal delivery by an agent of the Administrator. B. However, if the Administrator finds that any such violation presents an imminent and substantial danger of causing harmful stormwater runoff impacts to its MS4 Page 49-^&f-39 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bald system or waters within the watersheds of the Commonwealth, it may issue, without advance notice or hearing, an emergency order directing such person to cease immediately all land -disturbing activities on the site and shall provide an opportunity for a hearing, after reasonable notice as to the time and place thereof, to such person, to affirm, modify, amend, or cancel such emergency order. If a person who has been issued an order is not complying with the terms thereof, the Administrator may request the County Attorney to institute a proceeding for an injunction, mandamus, or other appropriate remedy. C. This "Sstop Wwork Oerder" shall be in effect until the County confirms that the land- disturbing activity is in compliance with the requirements of this Ordinance and the violation has been satisfactorily addressed. Upon failure to comply within the time specified, the permit may be revoked and the applicant shall be deemed to be in violation of this article and upon conviction shall be subject to the penalties provided by this Ordinance. Section 23-9.4 CIVIL AND CRIMINAL PENALTIES A. Any person violating or failing, neglecting, or refusing to obey any rule, regulation, ordinance, order, approved standard or specification, or any permit condition issued by the Administrator may be compelled in a proceeding instituted in the Roanoke County Circuit Court to obey same and to comply therewith by injunction, mandamus, or other appropriate remedy. B. Any person who violates any provision of this Ordinance or who fails, neglects, or refuses to comply with any order of the Administrator, shall be subject to a civil penalty not to exceed $32,500 for each violation within the discretion of the court. Each day of violation of each requirement shall constitute a separate offense. C. Violations for which a penalty may be imposed under this Subsection include, but are not limited to the following: 1. No state permit registration; 2. No SWPPP; 3. Incomplete SWPPP; 4. SWPPP not available for review; 5. No approved erosion and sediment control plan; 6. Failure to install stormwater BMPs or erosion and sediment controls; 7. Stormwater BMPs or erosion and sediment controls improperly installed or maintained; 8. Operational deficiencies; Page 49-64-39 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bold 9. Failure to conduct required inspections; 10. Incomplete, improper, or missed inspections; andaP 4 11. Discharges not in compliance with the requirements of Section 9VAC25- 880-70 of the general permit.-. D. The Administrator may issue a summons for collection of the civil penalty and the action may be prosecuted in the appropriate court. E. In imposing a civil penalty pursuant to this Subsection, the court may consider the degree of harm caused by the violation and also the economic benefit to the violator from noncompliance. F. Any civil penalties assessed by a court as a result of a summons issued by the County shall be paid into the County treasury to be used for the purpose of minimizing, preventing, managing, or mitigating pollution of the waters of the County and abating environmental pollution therein in such manner as the court may, by order, direct. G. With the consent of any person who has violated or failed, neglected or refused to obey this Ordinance or any condition of a permit, the County may provide, in an order issued by the A d m i n i s t r a t o rCeu4ty against such person, for the payment of civil charges for violations in specific sums indicated in the followinq schedule: �,�-tie eed + �+ - ----earChange provided to 6hdo-osmAn R Af tm6 S; Ah An, Aharoes; ?1�.h �hP Fl6tea.J�" allow assessment of civil charges. Amounts coordinate with those in E&SC Ordinance. 1. Commencement of land disturbing activity without receiving coverage under the General Permit from the Department shall be one thousand 4„ dollars ($17,0&00.00) per day. 2. Commencement of land disturbinq activity without preparation of a SWPPP shall be five hundred 4v dollars ($500&.00) per day. 3. Commencement of land disturbing activity with an incomplete SWPPP, or failure to properly amend a SWPPP to reflect changes in design, construction, operation, or maintenance that has a significant effect on the discharge of pollutants to surface waters and has not been previously addressed in the SWPPP shall be three&e*eT hundred dollars ($37-0&0.00) per day; 4. State permit registration statement not posted, or SWPPP not available for review shall be three hundred dollars ($300.00) per day. 5. Failure to comply with SWPPP requirements shall be three hundred dollars ($300.00) per day; Page 49 -^mfr -39 REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bold 6. Failure to conduct and document reauired inspections shall be three hundred dollars ($3800.00) per day. 7. Incomplete, improper, or missed inspections, including lack of proper signature shall be three hundred dollars ($300.00) per day. 8. Discharges not in compliance with the requirements of Section 9VAC25- 880-70 of the general permit shall be three hundred dollars ($300.00) per day. 9. Failure to obey a stop work order shall be one thousand dollars ($1,000.00) per day. 10. Failure to stop work when a permit is revoked shall be one thousand dollars ($1,000.00) per day. H. The total civil charges are not to exceed the limit specified in subdivision B of this section. Such civil charges shall be instead of any appropriate civil penalty which could be imposed under subdivision B. Any civil charge shall be paid into the County treasury to be used for the purpose of minimizing, preventing, managing, or mitigating pollution of the waters of the County and abating environmental pollution. Notwithstanding any other civil or equitable remedy provided by this Section or by law, any person who willfully or negligently violates any provision of the Ordinance, any order of the Administrator, any condition of a permit, or any order of a court shall, be guilty of a misdemeanor punishable by confinement in jail for not more than 12 months or a fine of not more than $2,500, or both. A. Any violator may be required to restore land to its undisturbed condition or in accordance with a notice of violation, stop work order, or permit requirements. B. In the event that restoration is not undertaken within a reasonable time after notice, the County may take necessary corrective action, the cost of which shall be covered by the performance security, or become a lien upon the property until paid, or both. Section 23-9.6 HOLDS ON CERTIFICATE OF OCCUPANCY Final certificates of occupancy may not be granted, at the discretion of the (Administrator{, - Added language to until corrections have been made in accordance with the approved plans, notices of make sure that it was clear that tMswas violation, stop work order, or permit requirements, and accepted by the County. discretionary. REVISED JANUARY 26, 2016 --------------------------------------------------- Formatted: Font: (Default) +Body (Calibri), Bold -END- Summary of revisions to be made to Stormwater Management Design Manual General all chapters will: • Have updated references to current manuals. • Spelling/grammar corrections. • Acronyms and units revised to correct nomenclature. Many chapters have numerous minor changes in technical or procedural requirements in response to our experience over the past year running the local Virginia Stormwater Management Program (VSMP). Following are some of the more significant proposed changes: Chapter 1 - Require additional information for development with wetlands: o Require wetland delineation, a copy of wetland permits, wetland flagging in the field, and wetlands to be shown on the plans. o Defines who can provide a wetland delineation shall be performed by a professional experienced in wetland delineation. Chapter 2 - Require stormwater master plan for phased plans in a common plan development. • Chapters 2 & 5 - Require additional information for stormwater plans to improve review efficiency and recordkeeping. o Requires the use of State Plane Coordinate system for horizontal control and NAVD 88 for vertical elevations. o Requires information for proposed channels to improve review efficiency and recordkeeping. • Chapter 8 - Add section on residential lot grading and drainage: o Require more grading and drainage information on initial subdivision site plans. o Require plot plans to be consistent with approved grading plan. Chapter 15 - Expand the requirements for as -built (record) drawings: o Need more consistent format to facilitate obtaining information for GIS. o Provide more direction as to what is required on as built drawings. o Requires submission of digital CAD files (to assist with GIS updates and County tracking). COUNTY OF ROANOKE STORMWATER MANAGEMENT DESIGN MANUAL �.�n �»X 1, 2016 ALLY!,TT Department of Community Development 5204 Bernard Drive Roanoke, Virginia 24018 r,rLY 1,204-4x 1, 2016 TABLE OF CONTENTS COUNTY OF ROANOKE STORMWATER MANAGEMENT DESIGN MANUAL IWNDIW.Ty01 Roanoke County's intent is to comply with the state Stormwater Management Law and Regulations, through implementation of the Roanoke County Stormwater Management Ordinance. All BMPs proposed for use in the County must be previously approved by DEQ and they must be contained on the VA BMP Clearinghouse. This Design Manual has local requirements that aid in the implementing of the state requirements and that supplement the state requirements. This ML X42016 edition of the Design Manual replaces the Septa .43er- 11, 2007July 1, - - Formatted: Highlight 2014 Design Manual, as approved by the Board of Supervisors by Resolution Formatted: Highlight oat'^. Due to the complexity of the subject, it is necessary for engineers and designers to be familiar with the information contained in all of the references listed in Section 1.8 of this manual. COUNTY OF ROANOKE i TABLE OF CONTENTS q444X/1/16- TABLE OF CONTENTS (Chapter 1— Introduction 1.1 Manual Purpose...............................................................................................1-1 1.2 Water Programs Regulatory Background......................................................1-1 2.3 1.2.1 Erosion and Sediment Control Program.................................................1-2 2.34 1.2.2 Stormwater Management Program.........................................................1-2 2.45 1.2.3 Floodplain Management Program........................................................... 1-2 2.56 1.2.4 Illicit Discharge Detection and Elimination Program.............................1-2 1.2.5 Municipal Separate Storm Sewer System (MS4) Permit ........................1-2 1.3 Contents of the Manual....................................................................................1-3 1.4 Authority...........................................................................................................1-4 1.5 Applicability.....................................................................................................1-4 1.6 Administration..................................................................................................1-4 1.6.1 General...................................................................................................1-4 1.6.2 Manual Amendments..............................................................................1-5 1.6.3 Exceptions..............................................................................................1-5 1.6.4 Appeal of Decisions...............................................................................1-5 1.7 Approval and Permits......................................................................................1-5 1.7.1 Local Approvals and Permits..................................................................1-5 1.7.2 Water and Sewer Approvals and Permits ................................................ 1-5 1.7.3 Joint Permit Application ...................................... .................... ............. 1-6 1.8 Reference Sources............................................................................................1-6 1.8.1 County of Roanoke Code and Ordinances .............................................. 1-6 1.8.2 Virginia Law and Regulations................................................................1-7 1.8.3 Virginia Manuals, Handbooks and Websites .......................................... 1-7 1.9 Acronyms and Abbreviations..........................................................................1-7 Appendix 1A — Roanoke County Policy on Common Plan of Development or Sale Chapter 2 Stormwater Management Plan Review and Approval 2.1 Overview of the Review and Approval Process..............................................2-1 2.2 Concept Stormwater Management Plan Submittal.......................................2-1 2.3 Stormwater Management Master Plan Submittal.........................................2-1 2.34 Stormwater Management Plan Submittal......................................................2-1 2.45 Submittal of Stormwater Calculations...........................................................2-2 2.56 Changes and Modifications to an Approved Plan..........................................2-3 Chapter 3 Easements 3.1 General..............................................................................................................3-1 3.2 Drainage Easements.........................................................................................3-1 3.2.1 Culverts and Storm Drains...................................................................... 3-2 3.2.2 Open Channels....................................................................................... 3-3 3.3 Access Easements.............................................................................................3-4 3.4 Maintenance of Easements.............................................................................. 34 - - Commented [AG1]: This page will need to be updated once all revisions have been made. COUNTY OF ROANOKE ii TABLE OF CONTENTS q444X/1/16- TABLE OF CONTENTS Appendix 3A — Standard Easement Agreements (Chapter 4 Stormwater Hydrology 4.1 References.........................................................................................................4-1 5.2.1 Major and Minor Channels..................................................................... 4.2 Design Frequencies...........................................................................................4-1 5-1 5.2.3 Hydrology.............................................................................................. 4.2.1 General...................................................................................................4-1 5.2.4 Channel Hydraulics................................................................................ 5-2 4.2.2 Storm Drainage Systems........................................................................4-1 5.2.6 Channel Slope........................................................................................ 4.2.3 Stormwater Management Facilities........................................................4-2 5.2.7 Cross Sectional Area.............................................................................. 4.3 Time of Concentration (t�) and Travel Time(Tt)...........................................4-2 5-5 5.2.9 Freeboard Requirements......................................................................... 4.3.1 General...................................................................................................4-2 5.2.10 Calculation of Depth of Flow at Bends and Curves ................................ 5-7 4.3.2 Overland Flow........................................................................................4-2 5-7 5.3 Environmental Considerations and Fishery Protection ................................ 4.3.3 Shallow Concentrated Flow....................................................................4-3 5.5 Maintenance Requirements............................................................................. 5-8 4.3.4 Channelized Flow...................................................................................4-3 4.3.5 Pipe Flow...............................................................................................4-3 4.4 Selection of Methodologies...............................................................................4-3 4.4.1 General...................................................................................................4-3 4.4.2 Peak Discharge Methods for Design of Storm Drainage Systems ..........4-4 4.4.3 Hydrograph Methods for Design of Stormwater Management Facilities 4-4 4.5 Methodologies...................................................................................................4-4 4.5.1 Rational Method.....................................................................................4-4 4.5.2 Modified Rational Method.....................................................................4-6 4.5.3 SCS Method...........................................................................................4-7 Appendix 4A — Design Aids, From Chapter 6, VDOT Drainage Manual Appendix 4B — Design Aids, From Chapter 4, VA SWM Handbook Appendix 4C — Information from VDOT Hydraulic Design Advisories Chapter 5 Open Channels 5.1 References.........................................................................................................5-1 5.2 Design Methodology and Criteria...................................................................5-1 5.2.1 Major and Minor Channels..................................................................... 5-1 5.2.2 Design Flow........................................................................................... 5-1 5.2.3 Hydrology.............................................................................................. 5-1 5.2.4 Channel Hydraulics................................................................................ 5-2 5.2.5 Channel Velocity....................................................................................5-2 5.2.6 Channel Slope........................................................................................ 5-3 5.2.7 Cross Sectional Area.............................................................................. 5-4 5.2.8 Channel Lining....................................................................................... 5-5 5.2.9 Freeboard Requirements......................................................................... 5-6 5.2.10 Calculation of Depth of Flow at Bends and Curves ................................ 5-7 5.2.11 Channel Location and Width Restrictions on Residential Lots ............... 5-7 5.3 Environmental Considerations and Fishery Protection ................................ 5-8 5.5 Maintenance Requirements............................................................................. 5-8 COUNTY OF ROANOKE iii TABLE OF CONTENTS q444X/1/16- TABLE OF CONTENTS 5.6 Floodplain Studies............................................................................................5-8 Appendix 5A — Aids for Open Channel Design, From Chapter 7, VDOT Drainage Manual_ , - Commented [AGz]: Revise COUNTY OF ROANOKE iv TABLE OF CONTENTS q444X/1/16- TABLE OF CONTENTS Chapter 6 Culverts 6.1 References.........................................................................................................6-1 6.2 Design Methodology and Criteria...................................................................6-2 6.2.1 Computation Methods............................................................................ 6-2 6.2.2 Hydrology.............................................................................................. 6-2 6.2.3 Culvert Hydraulics.................................................................................. 6-2 6.2.4 Structural Design....................................................................................6-5 7-2 6.2.5 Materials.................................................................................................6-6 7-3 6.2.6 Culvert Sizes.......................................................................................... 6-7 6.2.7 End Conditions.......................................................................................6-7 7-7 6.2.8 Multiple Barrel Culverts.........................................................................6-8 6.2.9 Culvert Skew..........................................................................................6-8 6.2.10 Buoyancy................................................................................................6-8 7.3 6.2.11 Debris and Trash Racks..........................................................................6-9 7-10 6.3 Installation........................................................................................................ 6-9 6.3.1 Bedding Material.................................................................................... 6-9 6.3.2 Backfill...................................................................................................6-9 7-11 6.4 Environmental Considerations and Fishery Protection ................................ 6-9 6.5 Maintenance Requirements........................................................................... 6-10 Appendix 6A — Aids for Stormwater Culvert Design, From Chapter 8, VDOT Drainage Manual Chapter 7 Storm Drains 7.1 References.........................................................................................................7-1 7.2 Design Methodology and Criteria...................................................................7-1 7.2.1 Computation Methods............................................................................ 7-1 7.2.2 Hydrology.............................................................................................. 7-2 7.2.3 Design Flows..........................................................................................7-2 7.2.4 Measures to Convey Stormwater Runoff to Inlets .................................. 7-2 7.2.5 Storm Drain Inlets.................................................................................. 7-3 7.2.6 Storm Drain Pipes.................................................................................. 7-5 7.2.7 Determination of Hydraulic Grade Line ................................................. 7-7 7.2.8 100 -Year Conditions............................................................................7-10 7.2.9 Materials...............................................................................................7-10 7.2.10 Structural Design..................................................................................7-10 7.3 Installation...................................................................................................... 7-10 7.3.1 Bedding Material..................................................................................7-11 7.3.2 Backfill.................................................................................................7-11 7.3.3 Separation of Utilities........................................................................... 7-11 7.4 Environmental Impacts................................................................................. 7-11 7.5 Erosion Protection at Outfalls.......................................................................7-11 7.6 Maintenance Requirements...........................................................................7-11 COUNTY OF ROANOKE v TABLE OF CONTENTS q444X/1/16- TABLE OF CONTENTS Appendix 7A — Aids for Storm Drain System Design, From Chapter 9, VDOT Drainage Manual Appendix 7B — Installation Procedures Chapter 8 Residential Lot Drainage 8.1 References.........................................................................................................8-1 8.2 General Lot Grading ........ ................................................................................ 8-1 8.3 Construction Plan Reguirments......................................................................8-1 Chapter 9 (NOT USED) Chapter 10 Energy Dissipation 10.1 References.......................................................................................................10-1 10.2 Design Methodology and Criteria.................................................................10-2 10.2.1 Outlet Velocity..................................................................................... 10-2 10.2.2 Erosion Control Stone..........................................................................10-2 10.2.3 Riprap Outlet Basins............................................................................. 10-2 10.2.4 Baffled Outlets.....................................................................................10-3 10.2.5 Energy Dissipator for Paved Areas ....................................................... 10-4 10.2.6 Additional Energy Dissipators.............................................................. 10-4 10.3 Installation Requirements..............................................................................10-5 10.4 Easements.......................................................................................................10-5 10.5 Environmental Impacts.................................................................................10-5 10.6 Maintenance Requirements...........................................................................10-5 Appendix 10A — Aids for Energy Dissipation Design, From VDOT Drainage Manual Appendix 10B — Aids for Energy Dissipation Design, From VDOT Road and Bridge Standards Appendix 10C — Energy Dissipation Design Schematics Chapter It (NOT USED) Chapter 12 Environmentally Sensitive Areas 12.1 References.......................................................................................................12-1 12.2 Floodplains......................................................................................................12-2 12.2.1 Applicant Flood Study Requirements................................................... 12-3 12.2.2 Floodplain Delineation.........................................................................12-5 12.3 Steep Slopes....................................................................................................12-5 12.3.1 Development Restrictions..................................................................... 12-5 12.3.2 Design Standards.................................................................................. 12-5 12.4 Stream Buffers................................................................................................12-6 12.5 Critical Erosion Areas....................................................................................12-6 COUNTY OF ROANOKE vi TABLE OF CONTENTS q444X/1/16- TABLE OF CONTENTS 12.6 Karst Geology.................................................................................................12-7 12.7 Stormwater Hot Spots....................................................................................12-8 12.7.1 Design Restrictions............................................................................... 12-9 12.7.2 Golf Course Development....................................................................12-9 Appendix 12A — Design Aids, From Local Assistance Manual, Chesapeake Bay Local Assistance Department Chapter 13 Geotechnical Studies (RESERVED) Chapter 14 Maintenance of Stormwater Management Facilities 14.1 Responsibility for Maintenance.....................................................................14-1 14.2 Maintenance Agreements..............................................................................14-1 14.3 Maintenance Program...................................................................................14-2 14.4 Additional Maintenance and Repair.............................................................14-5 14.5 Inspection and Maintenance Records...........................................................14-5 14.6 References.......................................................................................................14-5 Appendix 14A — Maintenance Agreements Appendix 14B — Maintaining Stormwater Systems, A Guidebook for Private Owners and Operators in Northern Virginia Chapter 15 Inspection and Enforcement 15.1 Construction Inspections...............................................................................15-1 15. 1.1 Notifications to the County of Roanoke...............................................15-1 15.1.2 Periodic Inspections.............................................................................. 15-2 15.1.3 Final Inspection and As -Built Documentation......................................15-2 15.2 Post -Construction Inspections and Maintenance.........................................15-3 15.3 Records...........................................................................................................15-4 15.4 Enforcement...................................................................................................15-4 15.4.1 Notice of Violation...............................................................................15-4 15.4.2 Stop Work Orders................................................................................. 15-5 15.4.3 Restoration of Land.............................................................................. 15-5 Appendix 15A — Inspection Forms , - Commented [AG3]: Revise COUNTY OF ROANOKE vii TABLE OF CONTENTS q444X/1/16- Chapter 1 - Introduction 1.1 Manual Purpose As land is developed and woodlands and pastures are converted to more intensive commercial and residential uses, the increase in impervious surfaces (pavements -+1+4, buildings etc_ and managed turf, cause adverse effects including: , - Formatted: Highlight • Increased flooding • Increased erosion and deposition of sediment in streams • Less base flow in streams due to less groundwater recharge • Increased runoff of pollutants (nutrients, sediment, bacteria, oil) • Decreased stream biodiversity (e.g.,aquatic insects and fish) • Loss of recreational uses such as swimming and fishing The County of Roanoke stormwater management goals are to minimize these adverse effects of land development by implementing effective stormwater management Best Management Practices (BMPs) as required by the County Code for new and redevelopment, and over , - I Formatted: Highlight time, by providing BMP measures to mitigate the adverse effects of past land development activities. The County of Roanoke Stormwater Management Design Manual, hereafter called the Design Manual, contains local requirements that supplement local ordinances, state regulations and guidance, and federal regulations. In general, D eet* direction and guidance from these sources is not repeated in this Design Manual. Refer to the listing of Reference Sources at the end of this chapter. 1.2 Water Programs Regulatory Background The County of Roanoke implements, and is regulated by, several water programs as briefly described below. Land Disturbing Activities are regulated under the erosion and sediment control, stormwater management, and floodplain management programs. Existing Development is regulated by the illicit discharge detection and elimination program and, if the property contains a permanent BMP, by the stormwater management program. The County of Roanoke itself is regulated by the MS4 Permit program. While the MS4 permit only directly regulates the County, it may indirectly impact anyone living in, owning property, or developing in the County of Roanoke through the impact of County actions that are required by its permit. COUNTY OF ROANOKE 7444X/1/16 1-1 INTRODUCTION 1.2.1 Erosion and Sediment Control Program The County is the local Erosion and Sediment Control (E&SC) authority. E&SC requirements are contained in the County of Roanoke Erosion and Sediment Control Ordinance and Virginia Erosion and Sediment Control Regulations. The County administers the program under the oversight of the Virginia Department of Environmental Quality (DEQ). 1.2.2 Stormwater Management Program The County is the local Virginia Stormwater Management Program (VSMP) authority. VSMP requirements are contained in the County of Roanoke Stormwater Management Ordinance and Virginia Stormwater Management Regulations. The County administers the program with oversight of the DEQ. The proper understanding of the meaning of "common plan of development or sale" is critical to understanding the applicability of stormwater management requirements for land disturbing activities. The County's policy concerning common plan of development or sale is contained in Appendix IA. 1.2.3 Floodplain Management Program The County regulates development in the floodplain through its Zoning Ordinance. This Program was developed and is administered to comply with Federal Emergency Management Agency requirements. 1.2.4 Illicit Discharge Detection and Elimination Program Except for specific limited exceptions, only uncontaminated stormwater may be discharged into stormwater systems. The County operates an Illicit Discharge Detection and Elimination Program in accordance with the County of Roanoke Illicit Discharge Ordinance, as required by its MS4 Permit. The DEQ provides oversight of this program. 1.2.5 Municipal Separate Storm Sewer System (MS4) Permit The County of Roanoke is regulated under a General Permit for Small Municipal Separate Storm Sewer Systems issued by the DEQ. MS4 permits generally impact urban areas and they require the locality to implement specific Minimum Control Measures (MCM) to protect local water quality. These MCM's generally fall into six 61 categories: 1. Public Education and Outreach on Stormwater Impacts 2. Public Involvement and Participation 3. Illicit Discharge Detection and Elimination 4. Construction Site Stormwater Runoff Control 5. Post Construction Stormwater Management COUNTY OF ROANOKE 7444X/1/16 1-2 INTRODUCTION 6. Pollution Prevention and Good Housekeeping for Municipal Operations The MS4 Permit also requires that the locality address water impairments that are identified by a Total Maximum Daily Load (TMDL) Study where the locality has been given a Waste Load Allocation (WLA). The County of Roanoke has WLA' for a number of its streams for impairments caused by sediment, bacteria, and PCB'' -s. See the Roanoke County website, Department of Community Development, Stormwater Management page for more information concerning the MS4 Permit and TMDL's. 1.3 Contents of the Manual —The Design Manual is divided into 15 chapters. An overview of each chapter is presented below. Chapter 1 — Introduction. Chapter 1 presents the general background and purpose behind the Design Manual. The chapter documents the goals of the program, the applicable requirements for stormwater management, and the administration of the program. Chapter 2 — Stormwater Management Plan Review and Approval. Chapter 2 presents the process that the applicant and the County of Roanoke follow to assure that the requirements of the stormwater management program and the Stormwater Management Ordinance are met. Chapter 3 — Easements. Chapter 3 establishes the requirements for easements for BMPs and storm drainage systems. Chapter 4 — Stormwater Hydrology. Chapter 4 documents the hydrologic design practices used to establish design flows necessary to design storm drainage systems and BMPs. Chapter 5 — Open Channels. Chapter 5 presents the requirements for open channel hydraulics, including cross section requirements, side slopes, widths, slopes, channel linings, and calculation methods. Chapter 6 — Culverts. Chapter 6 presents the requirements for culverts, including materials, slopes, headwater and tailwater limitations, and design calculation methods. Chapter 7 — Storm Drains. Chapter 7 presents the requirements for storm drains, including storm drain piping sizes, and lengths, and storm drain inlet hydraulics. Chapter 8 —Residential Lot Drainage. 'pP'S��Chapter 8 presents the requirements for residential lot drainage by providing drainage and/or grading the land to direct surface drainage away from building and toward streets, drainage conveyance structures, or sheet flow. COUNTY OF ROANOKE 7444X/1/16 1-3 INTRODUCTION Chapter 9 – Stormwater Detention. Chapter 9 presents requirements and design criteria for stormwater storage facilities. Design criteria include location, sizing, requirements, site access, release rates, and spillway requirements.–T4&-we 4.04 44 r`1...,.re f 11. Chapter 10 – Energy Dissipation. Chapter 10 includes the requirements for velocity and energy reduction devices at the discharge from storm drains, culverts, open channels, and other stormwater management systems. Energy dissipation is required to prevent excessive velocities and erosion in downstream channels. Chapter 11– NOT USED. Chapter 12 – Environmentally Sensitive Areas. Chapter 12 presents requirements for development of environmentally sensitive areas including floodplains, stream buffers, steep slopes, erodible soils, and stormwater pollutant hot spots. Chapter 13 – Geotechnical Studies. (RESERVED) Chapter 14 – Maintenance of Stormwater Management Facilities. Chapter 14 presents the requirements for establishing a maintenance program for stormwater management facilities, and the establishment of a maintenance agreement to assure that stormwater management facilities are properly maintained. Chapter 15 – Inspection and Enforcement. Chapter 15 presents the inspection and enforcement procedures to ensure that construction of stormwater management facilities comply with the approved plans and are properly maintained post-construction.As-built , - Formatted: Highlight requirements are also addressed in this chapter. 1.4 Authority The Design Manual provides supplemental information to implement the provisions of the County Code as they pertain to stormwater management, including storm drainage, and land development. In the event that any part of this Design Manual is held to be illegal or void, this shall not have the effect of making illegal or void the Design Manual in its entirety, or any section thereof, which shall remain effective. 1.5 Applicability —The requirements of this Design Manual apply to all land disturbance activities requiring permits. COUNTY OF ROANOKE 7444X/1/16 1-4 INTRODUCTION —Portions of this Design Manual apply to maintenance and repair of stormwater management facilities and other best management practices after construction is completed. 1.6 Administration 1.6.1 General —The policies and procedures contained within this Design Manual shall be administered by the County of Roanoke, Director of Community Development (Director), or designee. 1.6.2 Manual Amendments This Design Manual may be periodically amended, as recommended by the Director Formatted: indent: Left: 0.75", First line: o", Tab stops: of Community Development, or designee, and approved by the Board of Supervisors. o.7s", Left Amendments to this Design Manual will be posted on the County website, and will — - - Formatted: indent: Left: 0.75", First line: o", Tab stops: become effective on the date listed on the website. It is the manual user's 0.75 , Le ft responsibility to check the website and verify that they have the latest - - Formatted: Font: Bold requirements. 1.6.3 --Exceptions Requests for exceptions of any provisions of this Design Manual shall be made in writing to the County of Roanoke, Director of Community Development. The exception request shall clearly identify the Design Manual provision that is desired to be modified; the justification to support the issuance of an exception, and the alternative measures that are proposed to meet the intent of the Design Manual. All requests for an exception will receive a written response outlining the reasons for approval, or denial, after receipt of all information requested by the Director. In reviewing the request, the Director shall closely examine the proposed development and evaluate the variance request based on the conditions set forth in the Design Manual, County of Roanoke Code, Stormwater Management Ordinance; and the requirements and recommendations of the VA SWM Handbook, VDOT Drainage Manual, VA BMP Clearinghouse, and other sources. 1.6.4 Appeal of Decisions Appeals of decisions may be filed in accordance with the procedures provided in the County of Roanoke Code, Stormwater Management Ordinance. 1.7 Approvals and Permits The applicant is responsible for acquiring all required approvals and permits. 1.7.1 --Local Approvals and Permits COUNTY OF ROANOKE 7444X/1/16 1-5 INTRODUCTION The review and approval of stormwater management plans shall be an integral part of the overall review of site plans. Local permits and approvals include Erosion and Sediment Control Approval, Virginia Stormwater Management Program Permit, Land Disturbance Permit, Zoning Permit, and Building Permit. Retaining walls with a height of 2' or greater require a building permit. 1.7.2_ Water and Sewer Approvals and Permits Public water and sewer requires approval from either the Western Virginia Water Authority (WVWA) or the Town of Vinton_(, depending on the geographic location. 1 the site is located in the Town of Vinton or to the east of the Town of Vinton, within the Town of Vinton service area; then, Town of Vinton approval is required. If public water and/or sewer is located elsewhere in the County; then, WVWA approval is required. For areas not served by public water and sewer, local health department approval is required for wells and onsite sanitary sewage disposal. 1.7.3. --Joint Permit Application Wetlands and streams are protected under several Federal and State programs. Whenever jurisdictional wetlands or streams are impacted by land disturbing activities, a Joint Permit Application must be completed and filed with the Virginia Marine Resources Commission (VMRC). VMRC will distribute the joint permit application to The U.S. Army Corps of Engineers (E9EUSACE) and the Virginia Department of Environmental Quality (DEQ). The C-4h-USACE and DEQ will consult with other Federal and State agencies in processing the permit application. Upon receipt of an acceptable application the following permits may be issued: • GOC—USACE Federal Section 404 Permit • DEQ Water Protection Permit (VWP) • VMRC Permit The Design Professional shall provide She County of Roanoke a copy of the required _ - Formatted: Highlight wetland permit; or with written documentation that a wetland permit isnot required by \ ' Formatted: Highlight the USACE, DEQ, or VRMC. The written documentation shall be prepared Eby a 3rd Formatted: Highlight party professional experienced in wetland delineation. Plans shall show the surveyed Formatted: Highlight wetland boundary delineation-apA, provide geographic location of the wetland flags, provide acreage of wetlands, and linear footage of streams. Wetlands shall be numbered and flagged in the field. Wetland delineations shall be performed in accordance with the 1987 Corns of Eneineers Wetland Delineation Manual and the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Eastern Mountains and Piedmont Region. � - - Formatted: Indent: Left: 0.63", First line: 0" COUNTY OF ROANOKE 7444X/1/16 1-6 INTRODUCTION 1.8 Reference Sources Managing stormwater runoff from land disturbing activities and prior developed land is a complex issue. There are a number of laws, ordinances and guidance sources that those that design land disturbance activities (land development) must follow. The requirements and recommendations of the following sources, latest editions, are incorporated into this Design Manual by reference. All of the referenced sources are readily available on the internet. 1.8.1_ County of Roanoke Code and Ordinances Design and construction of land disturbing activities shall comply with all relevant portions of the County of Roanoke Code including: • Stormwater Management Ordinance • Erosion and Sediment Control Ordinance • Illicit Discharge Ordinance • Zoning Ordinance • Subdivision Ordinance 1.8.2_ Virginia Law and Regulations Design and construction of land disturbing activities shall comply with all relevant Virginia law and regulations including: • Virginia Stormwater Management Law • Virginia Erosion and Sediment Control Law • Virginia Stormwater Management Regulations • Virginia Erosion and Sediment Control Regulations 1.8.3 --Virginia Manuals, Handbooks, and Websites • Virginia Stormwater Management Handbook, Hereafter throughout this Design Manual referred to as the VA SWM Handbook. • Virginia Department of Transportation Drainage Manual. Hereafter throughout this Design Manual referred to as the VDOT Drainage Manual. COUNTY OF ROANOKE 7444X/1/16 1-7 INTRODUCTION • Virginia Department of Transportation Road and Bridge Standards. Hereafter throughout this Design Manual referred to as the VDOT Standards. • Virginia Department of Transportation Road and Bridge Specifications. Hereafter throughout this Design Manual referred to as the VDOT Specifications. • Virginia Erosion and Sediment Control Handbook. Hereafter throughout this Design Manual referred to as the VA E&SC Handbook. • Virginia Stormwater Management BMP Clearinghouse website (http://vwrrc.vt.edu/swc/). Hereafter throughout this Design Manual referred to as the BMP Clearinghouse. 1.9 --Acronyms and Abbreviations —For clarification, the following is a listing of abbreviations, and acronyms used in stormwater management and throughout this Design Manual. A – Drainage area, acres (stormwater hydrology) A – Cross section area, square feet (open channel or pipe hydraulics) B – VDOT rainfall coefficient, no units (stormwater hydrology) BMP – Best management practice C – Runoff coefficient, no units (stormwater hydrology) Cf– Saturation factor, no units (stormwater hydrology) CMP – Corrugated metal pipe CN – Curve Number (stormwater hydrology) GO&USACE – U.S. Army Corps of Engineers D – VDOT rainfall coefficient, no units (stormwater hydrology) DCR – Virginia Department of Conservation and Recreation De – Critical duration, minutes (stormwater hydrology) DEQ – Virginia Department of Environmental Quality E – VDOT rainfall coefficient, no units (stormwater hydrology) FEMA – Federal Emergency Management Agency g – Gravity coefficient, 32.2 feet/s2 H – Height or depth of water, feet Hf Hi, Hm, FL, Ho – Head losses in piping and structures, feet (storm drain hydraulics) HDPE – High density polyethylene HGL – Hydraulic grade line I – Rainfall intensity, inches per hour (stormwater hydrology) Ip.st – Post -development impervious cover, percentage (water quality Simple Method calculation) I xm.g – Existing impervious cover, percentage (water quality Simple Method calculation) K, Ki, Ko – Head loss coefficients for piping, no units COUNTY OF ROANOKE 7444X/1/16 1-8 INTRODUCTION Lp,e — Pre -development pollutant loading, pounds per year (water quality Simple Method calculation) Lp.st — Post -development pollutant loading, pounds per year (water quality Simple Method calculation) MS4 — Municipal Separate Storm Sewer System n — Manning's equation roughness coefficient, no units (open channel and pipe hydraulics) NFIP — National Flood Insurance Program Q — Stormwater flow, ^a"ars per rainote 'rtpm` at: cubic feet per second (ells) R—Hydraulic radius, feet (open channel hydraulics) r� — Stream bend radius, center, feet (open channel hydraulics) ri — Stream bend radius, inside bank, feet (open channel hydraulics) ro — Stream bend radius, outside bank, feet (open channel hydraulics) S — Slope, feet per feet (open channel or pipe hydraulics) or as a percentage (%) SCS — Soil Conservation Service t� — Time of concentration, hours—minutes (stormwater hydrology) Tp — Time to peak flow,1}ear--minutes (stormwater hydrology) Tr — Time to recede, 4oa�minutes (stormwater hydrology) Tt — Travel time, lminutes (stormwater hydrology) V, Vi, Vo — Velocity, feet per second (open channel and pipe hydraulics) VA E&SC Handbook — Virginia Erosion and Sediment Control Handbook, latest version, as amended VA SWM Handbook — Virginia Stormwater Management Handbook, latest version, as amended VDOT — Virginia Department of Transportation VDOT Drainage Manual — Virginia Department of Transportation, Drainage Manual, latest version, as amended VDOT Specifications — Virginia Department of Transportation, Road and Bridge Specifications, latest version, as amended VDOT Standards — Virginia Department of Transportation, Road and Bridge Standards, latest version, as amended VMRC — Virginia Marine Resources Commission VSMP — Virginia Stormwater Management Program, as administered by PSD DLQ and Roanoke County AZ — Difference in water surface elevation from the inside curve to the outside curve of an open channel, feet (open channel hydraulics) COUNTY OF ROANOKE 7444X/1/16 1-9 INTRODUCTION APPENDIX IA POLICY CONCERNING COMMON PLAN OF DEVELOPMENT OR SALE COUNTY OF ROANOKE '"4x/1/16 IA -1 INTRODUCTION Policy Concerning "Common Plan of Development or Sale" IA.1 General This policy explains how Roanoke County interprets and will apply "common plan of development or sale" in its local VSMP. In the event that this policy conflicts with any guidance issued by DEQ, DEQ guidance will govern. All land -disturbing activities, except those specifically exempted in Section 23-1.3 of the Roanoke County Stormwater Management Ordinance, require approval from Roanoke County as the local VSMP authority and coverage under the state General Permit for Discharges of Stormwater Ffem from Construction Activities prior to commencing land -disturbing activities. Several exemptions apply to land -disturbing activities that disturb less than one acre of land and that are not part of a larger common plan of development or sale. In order to properly apply these exemptions, it is necessary to understand what is meant by "common plan of development or sale." It is critical for developers and land -owners to understand that the permitting exemption can be lost by disturbing more area on a project than planned (exceeding 1 acre land - disturbance) or by taking actions that demonstrate that a small project (less than 1 acre land -disturbance) is part of a larger common plan of development or sale. Actions that increase land disturbance or that create a larger common plan of development after plan approval and during construction will necessitate securing a VSMP permit, may result in possible enforcement and penalty actions, and may result in additional costs and delays due to the need to redesign the site and construct or modify BMPs. Land disturbing activities that are exempt from the requirements of the Stormwater Management Ordinance may not be exempt from the Erosion and Sediment Control stormwater management requirements. Erosion and Sediment Control regulations could still require stormwater management to address Minimum Standard 19. 1A.2 State Definition and Guidance 9VAC25-870-10 defines common plan of development or sale in the following manner: "Common plan of development or sale" means a contiguous area where separate and distinct construction activities may be taking place at different times on different schedules. For the purposes of the VSMP regulations, individual lots within existing residential, commercial, or industrial site plans and subdivision plans that were platted prior to July 1, 2004 may be considered separate land -disturbing activities. COUNTY OF ROANOKE 7444-x/1/16 INTRODUCTION IA -2 1A.3 Discussion and Application 1A.3.1 USEPA guidance(-http://cfpub.epa.gov/npdes/fags.cfm?program id=6 ) A "larger common plan of development or sale" is a contiguous area where multiple separate and distinct construction activities may be taking place at different times on different schedules under one plan. For example, if a developer buys a 20 -acre lot and builds roads, installs pipes, and runs electricity with the intention of constructing homes or other structures sometime in the future, this would be considered a larger common plan of development or sale. If the land is parceled off or sold, and construction occurs on plots that are less than one acre by separate, independent builders, this activity still would be subject to stormwater permitting requirements if the smaller plots were included on the original site plan. The larger common plan of development or sale also applies to other types of land development such as industrial parks or well fields. A permit is required if one (1) or more acres of land will be disturbed, regardless of the size of any of the individually -owned or developed sites. 1A.3.2 The creation of a common plan of development or sale A common plan of development or sale comes into being when there is documentation showing plans or intent to disturb earth regardless of how many phases or how long it will take. Common documents that create a common plan of development include: (a) any announcement or documentation (marketing plans, sign, sales pitch, notice, etc_); (b) any physical demarcation (boundary signs, lot stakes) indicating construction may occur on a specific plot; (c) subdivision plats; or, (d) construction drawings. 1A.3.3 The completion of a common plan of development or sale Once a common plan of development or sale has been created, it remains in force until the contemplated development is substantially completed (less than one (1) acre remaining to be developed). There may be a time when a new developer will want to perform a land disturbing activity on an undeveloped parcel (that was created on or after July 1, 2004), and wants to know if a common plan of development or sale is still valid. In order for the new activity to not be a part of the original common plan of development or sale, it must meet 2 tests. Test 1: Was the original plan, including modifications, ever substantially completed with less than one (1) acre of the original common plan of development or sale remaining (e.g., less than one (1) acre remains to build out)? Test 2: Has there been a clearly identifiable period of time where there is no on- going construction, including meeting criteria for final stabilization? (Roanoke County, by this policy, sets the clearly identifiable period of time at one (1) year.) If the project meets the two tests, then it may be evaluated for permitting purposes on its individual merits. If it does not meet either of the two tests, then it remains part of the original common plan of development or sale, and it requires permit coverage. COUNTY OF ROANOKE 7444--x/1/16 IA -3 INTRODUCTION 1A.3.4 Additional development on an individual parcel after the intended construction is completed When the intended construction on a parcel that is part of a larger common plan of development or sale is completed, any subsequent development or redevelopment of that parcel is considered a new plan of development. 1A.3.5 Effect of adding property to an existing project There are 2 cases where adding land to a project could have permitting impacts. Case 1: A common plan of development or sale has already been created and development of the common plan of development or sale is ongoing. The developer purchases additional property to incorporate into the development. The additional property would become part of the common plan of development or sale. Case 2: A developer subdivides a parcel to create a residential lot. The development of the lot will disturb less than 1 acre. No stormwater permit is required. Prior to a clearly identifiable period of time (1 year) where there is no on-going construction on the first lot, the developer creates a second lot from the original parcel (or markets additional homes prior to creating lots). The development of the second lot would disturb less than 1 acre; however, the development of the first lot and the second lot together would cumulatively disturb 1 acre or more. A larger common plan of development or sale has been created. A permit is required to cover the entire common plan of development or sale (both the construction on Lot 1 as well as Lot 2 and any subsequent lots). Construction on Lot 1 would need to halt until permitting is completed. Stormwater management requirements would need to be met for the entire common plan of development or sale. 1A.3.6 Timing for construction and ownership of BMPs for a common plan of development or sale The technical criteria for stormwater management must be applied to the entire common plan of development or sale. In some cases, portions of a common plan of development or sale may have BMPs with a higher efficiency of pollutant removal or stormwater volume or rate control than other portions of the common plan of development or sale. However, no portion of the common plan of development or sale shall be considered by the County to be completed or be allowed to be occupied until BMPs are completed and functioning that provide stormwater management for that portion of the common plan of development or sale adequate to meet minimum standards (e.g., the construction of BMPs cannot be deferred to a later phase, if the portion of the common plan of development or sale that is currently under construction does not have adequate BMPs to meet the stormwater management technical criteria). COUNTY OF ROANOKE 7444-x/1/16 IA -4 INTRODUCTION BMPs that provide stormwater management for one individual parcel may be on the individual parcel and may be owned and maintained by the property owner of the individual parcel. At the developer's option, BMPs that provide stormwater management for one individual parcel may be made a property association's responsibility as described in the next paragraph. BMPs that provide stormwater management for more than one parcel must be owned and maintained by a property association, consisting of all property owners that are benefiting from the BMP. 1A.3.7 De minimus land disturbance Neither federal nor state definitions or guidance address de minimus land disturbance on a lot within a larger common plan of development or sale. It is obvious that at some point, minor land disturbing activities should not be regulated, within a larger common plan of development or sale; example — disturbance of 20 square feet, on a lot, to erect a temporary sign. For the purpose of implementing the VSMP, Roanoke County considers land disturbance of less than 2,500 square feet to be de minimus and will not fall under the VSMP regulations. If any additional land disturbance occurs on a lot, within a larger common plan of development or sale, within one (1) year of completing the original disturbance, the land disturbance area will be summed. If the summed land disturbance is greater than 2,500 square feet, then the total land disturbed must comply with the VSMP regulations. 1AA Examples 1A.4.1. Example 1 A residential subdivision was started after July 1, 2004. Only 60 of the 100 lots have been developed, with the remaining 40 lots constituting 1 acre or more. No development has occurred since around 2010. A developer intends to develop a vacant'/2 acre lot. This situation applies to a vacant lot in accordance with Section M.3.3. The residential subdivision is a common plan of development or sale. While a clearly identifiable period of time of no construction has passed (Test #2), the project was never substantially completed (Test 91). Therefore, the developer requires a VSMP permit. 1A.4.2 Example 2 A residential subdivision was constructed around 2010. About 80 of the 100 lots have been developed, with the remaining 20 lots constituting 1 acre or more. The owner of one of the constructed homes intends to construct an addition to his home that will disturb 3,000 square feet. This situation applies to an individual parcel after intended construction has been completed in accordance with Section 1.3.4. The residential subdivision is a common plan of development or sale. However, the intended construction has been completed on this lot. Therefore, the addition is treated as a new development project. Since it disturbs less than I acre, no VSMP permit is required. COUNTY OF ROANOKE 7444-x/1/16 1A-5 INTRODUCTION 1A.4.3 Example 3 A regional shopping center was built in the 1990s. It is currently marketing plans to develop several additional buildings in its parking lot. It anticipates that the buildings will be constructed one at a time. The anticipated disturbed area for the construction of each building is less than 1 acre, but the anticipated disturbed area for the construction of all of the additional buildings is over an acre. The common plan of development or sale occurred prior to July 1, 2004, and the original plan is completed. Each of the proposed buildings will disturb under I acre; however, since the 3 buildings are being marketed together, a new common plan of development or sale has been created and the construction of all three buildings must be considered as a single land -disturbing activity. A VSMP permit is required. 1A.4.4 Example 4 A regional shopping center was built in the 1990's. The owner intends to construct a building expansion that will disturb 0.8 acres. Just over a year after completion of the expansion, the owner of the regional shopping center decides to construct another building in its parking lot. The building construction will disturb 0.7 acres. The common plan of development or sale occurred prior to July 1, 2004, and the original plan is completed. The developer intends to construct a building expansion as a stand- alone project. The project will disturb less than I acre; therefore, no VSMP permit is required. After a distinct time period (I year) has passed with no construction activity, the developer decides to construct another building in its parking lot. Since a distinct time period (I year) has passed since the completion of the building addition, and since the new building is not part of the building expansion plan, and since less than I acre is disturbed, no common plan of development or sale is created and no VSMP permit is required. Note If the building expansion and additional building in the parking lot were part of an overall renovation plan that was intended to be constructed in phases, then a common plan of development or sale would have been created and a VSMP permit would have been required. 1A.4.5 Example 5 A congregation intends to build a new church in phases. Phase 1 is for a multipurpose sanctuary and parking and the construction will disturb 2 acres. Phase 2 is for a classroom expansion and its construction will disturb 0.5 acres. The phased church construction is a common plan of development or sale. A VSMP permit will be required for Phase I and Phase 2. COUNTY OF ROANOKE 7444--x/1/16 IA -6 INTRODUCTION 1A.4.6 Example 6 A congregation intends to build a new wing for education use and expand the parking lot. No construction has been built for over a year. The construction will disturb 0.8 acres. The proposed project is separate from the original church construction; therefore, it is not part of a larger common plan of development or sale. Since disturbed area is less than I acre, no VSMP permit is required. 1A.4.7 Example 7 A developer has a plan approved that indicates that 0.9 acres will be disturbed. During construction, the developer actually disturbs 1.2 acres. The developer's plan indicates that less than I acre will be disturbed. Therefore, no VSMP permit was required. However, the developer actually disturbed over 1 acre. Therefore, the County issues a "Stop Work" order until a VSMP permit can be issued. A stormwater management plan meeting the stormwater management regulation technical requirements must be prepared and submitted, along with an executed and recorded maintenance agreement, revised performance security, and additional fees. The developer must ensure that an adequate SWPPP is prepared and available at the site. No further land -disturbance activities may occur until these items are completed and a VSMP permit is issued. The County may undertake other enforcement actions and penalties, depending on the circumstances. 1A.4.8 Example 8 An existing fast food restaurant is part of a partially developed commercial area. It plans a renovation that includes some parking lot changes and a small expansion to its seating area. The construction disturbed area is 0.7 acres. The commercial area is part of an active common plan of development or sale; however, the intended construction (fastfood restaurant) on this parcel has been completed. In accordance with Section M.3.4, the renovation is a separate land -disturbing activity. Since less than I acre is disturbed, no VSMP permit is required. 1A.4.9 Example 9 A developer intends to construct a subdivision in two phases. He intends to develop Phase 1 first, followed by Phase 2. Since the subdivision is a common plan of development or sale, the two phases are treated as a single land disturbance activity and the determination of whether or not adequate stormwater management is being provided is analyzed for the subdivision as a whole. Stormwater management for the subdivision will be accomplished by a combination of BMPs on individual lots, to serve the individual lots; and BMPs intended to serve multiple lots. Due to the characteristics of COUNTY OF ROANOKE 7444-x/1/16 IA -7 INTRODUCTION the site and the layout of the design, the overall plan indicates that the proposed BMPs for Phase 1 are not adequate to meet the pollutant removal requirements, but that with the construction of Phase 2, the overall effectiveness of the BMPs will be increased so they are adequate to meet the pollutant removal requirements for both Phase 1 and Phase 2 upon completion of Phase 2. The proposed plan is unacceptable in accordance with Section 1.3.6. Even though it is expected that portions of the common plan of development or sale will have more effective BMPs than other portions of the common plan of development or sale, and even though the common plan of development or sale is evaluated as a single land -disturbance activity; It is not acceptable to construct a portion of the common plan of development or sale without concurrent construction of adequate BMPs such that the technical requirements of the stormwater management regulations are met as each portion of the common plan of development or sale is completed. 1A.4.10 Example 10 A land -owner owns a parcel with existing public road frontage. The current zoning and subdivision requirements would allow for the parcel to be subdivided into 8 lots without the need for any additional public infrastructure. The property owner divides the parcel to create one 1/4 acre lot and constructs a single family house on it. Several years after completion of the single family house, the property owner divides the parcel again to create another 1/4 acre lot and constructs another single family house. Each project is separated by adequate time that they are independent projects and no VSMP permit is required. 1A.4.11 Example 11 A land -owner owns a 10 acre parcel with existing public road frontage. The current zoning and subdivision requirements would allow for the parcel to be subdivided into 8 lots without the need for any additional public infrastructure. The property owner divides the parcel to create one 1/4 acre lot and sells the individual lot to a developer to construct a single family house on it. After the property sale, the landowner posts a sign on his property stating that "land is available for development and that the owner will subdivide". The owner has created a larger common plan of development or sale by marketing development on his parcel. The developer may continue with his project to construct a single family house, since the property was sold to him prior to the creation of the larger common plan of development or sale. However, any further construction on the land- owner's parcel will require a VSMP permit. COUNTY OF ROANOKE 7444--x/1/16 IA -8 INTRODUCTION STORMWATER MANAGEMENT PLAN REVIEW AND APPROVAL CHAPTER 2 Chapter 2 — Stormwater Management Plan Review and Approval In order to maintain the character and integrity of neighborhoods, to promote excellence of development, to prevent undue traffic and environmental hazards, and to encourage the most harmonious development and use of land, a site development plan, including a storm water management plan and sediment control plan, is required for commercial and residential development and shall be submitted to the County of Roanoke's Department of Community Development. Plans should be submitted in compliance with the Digital Plan Submission Guide policy. (http://www.roanokecountyva.gov/index.aspx?NID=317) These plans will be distributed to the appropriate departments and divisions for review and approval. When required, the applicant is also responsible for submittals to the Virginia Department of Transportation, Virginia Department of Environmental Quality, Western Virginia Water Authority, Town of Vinton, and other applicable regulatory agencies for their review and approval. When applicable, all of these entities must approve the site development plan prior to the issuance of any permits for all types of developments as required by the Zoning Ordinance, Subdivision Ordinance, Erosion and Sediment Control Ordinance, and Stormwater Management Ordinance. In cases where jurisdictional waters exist on the proposed site, the applicant may need to obtain approvals and/or permits from any or all of the following agencies: the U.S. Army Corps of EngineersU( SACE), the Federal Emergency Management Agency, the Virginia Department of Environmental Quality (DEQ), and the Virginia Marine Resource Commission (VMRC). Itis the responsibility of the applicant to obtain all necessary permits from USACE, DEO, VRMC, etc and provide Roanoke County with a copy of the required permit(s). Approval of plans by Roanoke County does not alleviate the applicant's liability of obtaining the required permit(s). 2.1 Overview of the Review and Approval Process No application for land development, land use conversion, or land disturbance can be approved, and no permits issued, without all of the elements required for a VSMP permit, as more fully described in the County Stormwater Management Ordinance and 9VAC25-870- 55. These elements generally include a permit application, erosion and sediment control plan, stormwater management plan, stormwater maintenance agreement, performance bond, fees, and executed development agreements. An agreement in lieu of a stormwater management plan may be accepted for a detached single family residence that is not part of a common plan of development. —The submittal, review, and approval of site development plans, including stormwater management plans will follow the Roanoke County Land Development Procedures. This document is available from the County of Roanoke Department of Community Development website (http://www.roanokeco=va.gov/index.aspx?NID-317). COUNTY OF ROANOKE STORMWATER MANAGEMENT PLAN 7/A444x/1/16 REVIEW AND APPROVAL 2-1 Formatted: Highlight STORMWATER MANAGEMENT PLAN REVIEW AND APPROVAL CHAPTER 2 2.2 Concept Stormwater Management Plan Submittal A concept site development plan, including a concept stormwater management plan, is is strongly encouraged by the County of Roanoke when the proposed - - Formatted: Font: sold development meets any of the conditions set forth in the Roanoke County Land Development Procedures. A concept site plan or concept stormwater management plan may also be submitted for any project at the applicant's option. If submitted, the concept site development plan, including a concept stormwater management plan, should addressed items as outlined in Roanoke County's Land Development Procedures. 2.3 Stormwater Management Master Plan Submittal A stormwater management master plan and calculations are required for all phased proiects that are part of a common plan of development. The master plan shall address grading, stormwater conveyance, and stormwater management BMPs for the overall development. The master plan is required to be approved prior to issuance of any permits. Each phase must provide adequate stormwater treatment to address the stormwater requirements for each individual phase. The Stormwater Master Plan shall show how the Desiener will address stormwater management requirements for the entire proiect. At a minimum, the plans shall show the overall development, the location and type of the proposed BMPs required to treat the entire development, and contours. Additionally, the Designer shall provide applicable drainage areas to the BMPs and provide an accompanying VRRM worksheet to support the overall design" The final stormwater management master plan shall be appropriately sealed and signed by a licensed professional in adherence to all minimum standards and requirements pertaining to the practice of that profession as required in the VA Stormwater Management Regulations. 2.34 Stormwater Management Plan Submittal —An approved site development plan and a local VSMP permit, is executed agreement in lieu of a stormwater management plan, is required prior to issuance of any other permits. The final stormwater management plan shall be appropriately sealed and signed by a licensed professional in adherence to all minimum standards and requirements pertaining to the practice of that profession as required in the VA Stormwater Management Regulations. The VSMP permit application information will be reviewed by the County of Roanoke. In addition to Roanoke County's review, the Virginia Department of Transportation may also COUNTY OF ROANOKE 7/A444x/1/16 2-2 STORMWATER MANAGEMENT PLAN REVIEW AND APPROVAL Formatted: Highlight STORMWATER MANAGEMENT PLAN REVIEW AND APPROVAL CHAPTER 2 review the site development plan with the stormwater management plan, as appropriate. Plans for review by these entities must be submitted directly to them, when required. All commercial protects or sites within a common plan of development that disturb between 0.90 and 0.99 acres shall provide point(s) with northing and castings to delineate the disturbance limits on the plans. The plans shall include a note that the disturbance limits are required to be delineated by a surveyor in the field and orange safety fence shall be installed to mark the delineation. All plans required for single family protects that are part of a common plan of development or commercial proiects shall be prepared using the State Plane Coordinates and NAVD 88. Single family protects that are not part of a common plan of development and do not require as-builts nor a flood study are not required to be tied to the State Plane Coordinate System. 2.45 Submittal of Stormwater Calculations —Calculations shall be submitted to the County of Roanoke supporting the stormwater management and storm drainage design. Calculations shall be well organized and coordinated with the design to allow for efficient review by the County. Calculations shall be bound together in a booklet or stapled together, depending on the number of pages. Each page of She calculations should include the date .prepared, a, unique page number_, and the date , - Formatted: Highlight revised. Formatted: Highlight � Formatted: Highlight Calculations shall follow the following general format: Formatted: Highlight • Cover Sheet — The cover sheet shall contain the project name, property tax parcel(s) number(s), applicant's name, design professional's name, calculation date, and (for final calculations) the seal and signature of the design professional. • Table of Contents — A table of contents shall be provided where the calculations exceeds 25 pages, or where appropriate to assist the reviewer in locating information in the calculations. • Introduction — A general description of the project providing information to assist the reviewer in understanding the nature and scope of the project and of the storm drainage and stormwater management facilities that are proposed. This should also explain existing and proposed conditions. • Criteria and Methodology — A listing of the basic design criteria for water quality compliance, channel protection, flood protection, and TMDL (where appropriate). • References — A listing of references that are used in the calculations COUNTY OF ROANOKE STORMWATER MANAGEMENT PLAN 7/A444x/1/16 REVIEW AND APPROVAL 2-3 STORMWATER MANAGEMENT PLAN REVIEW AND APPROVAL CHAPTER 2 • Assumptions —A listing of all assumptions, and justification of the assumptions that are used in the calculations. • Analysis - The body of the calculations clearly labeled as to what stormwater BMPs or storm drainage system the calculations are for. The calculations shall be step-by- step to ensure that a reviewer that is not familiar with the project can follow the progression of the calculations. If computer printouts are provided highlight the input and output information and ensure that the input information is clearly supported in the calculationsand that the output is properly evaluated in the summary and conclusions. All calculation parameters must be fully supported and documented and include the design storm frequency, intensity and duration, times of concentration mans (including segment lengths, elevations, slopes, and flow types), soil curve numbers or runoff coefficients; calculations identifying pre -and post -development peak runoff rates and total runoff volumes for each watershed area, infiltration rates (where applicable), culvert, storm drain, and open channel capacities, flow velocities, data on the increase in rate and volume of runoff for the specified design storms, pre - and post -development phosphorous runoff rates and all other calculations needed to support the proposed design. • VRRM Worksheet — A digital copy of the VRRM worksheet shall be submitted with the plan submittal. Roanoke County uses an annual rainfall of 42" for all proiects located within Roanoke County and precipitation rates from the NOAA precipitation chart for the Roanoke County Airport. • Drainage Area Maps —Drainage area maps shall be provided for storm drainage inlets and BMPs. Pre and post drainage area maps shall be provided. • Summary and Conclusions — A summary of the results, preferably in tabular or chart form for each storm drain system and stormwater BMP to indicate that the land disturbing project meets County requirements and any conclusions. Provide Oi, 02, and Oio for pre and post conditions. Appendices and Attachments — Any supporting information such as pre -developed and post -developed drainage area maps, soils maps, U.S.G.S. quadrangle maps, NOAA precipitation chart, design nomographs, and computer printouts. Drainage maps must be clearly delineated and labeled to indicate the amount of area draining to each BMP and storm drainage inlet. Formatted: Underline Calculations that are not well organized and coordinated with the design shall be - I Formatted: Font: sold, Underline reiected and the submittal shall not be reviewed until proper calculations are submitted. COUNTY OF ROANOKE 7/A4 -/44x/1/16 2-4 STORMWATER MANAGEMENT PLAN REVIEW AND APPROVAL STORMWATER MANAGEMENT PLAN REVIEW AND APPROVAL CHAPTER 2 2.56 Changes and Modifications to an Approved Plan Changes to an approved subdivision or site plan, including an approved stormwater management plan, must be formally submitted for review to the County of Roanoke Department of Community Development at the counter with the Permit Technicians or via toe Roanoke County's FTP site. The County of Roanoke, upon receipt of the resubmittal of an approved development plan, shall review and approve or disapprove the resubmitted plan according to the Roanoke County Land Development Procedures. Approval or disapproval of the resubmitted plan shall be made in writing to the applicant. Any use, arrangement, location, or construction not in compliance with the approved plan is a violation of the County Code. COUNTY OF ROANOKE STORMWATER MANAGEMENT PLAN 7/A444x/1/16 REVIEW AND APPROVAL 2-5 EASEMENTS CHAPTER 3 Chapter 3 - Easements 3.1 General This manual addresses three types of easements: • Private drainage easements; • Public drainage easements; and • Access Easements Easements may be required as a part of a subdivision plat or site plan review. The purpose of this section is to provide policy, procedures, and guidelines for establishing easements for storm drainage and BMPs. Easements may grant certain rights and privileges to the County or other public entity such as VDOT for public easements, or to specific landowners and/or the County in the case of private easements. Proposed easements will be shown conceptually on preliminary site plans. The easements will be in final form on the submitted stormwater management plan and will be consistent with the design on final plats and site plans. Easements shall be dimensioned to allow them to be located in the field by providing dimensional ties to property corners, or centerline bearings and distances. Where easements are aligned with property lines, offset dimensions will be provided. Verification of easement locations will be required as a part of the as -built drawing requirements. If drainage or BMPs are found to have been constructed outside of the easement; then, the permittee will be responsible for vacating the original easement and recording a new easement, in the proper location, at the permittee's expense. Easements should not split property lines. Where an open channel or storm drain system runs parallel to a property line, it should be offset from the property line an adequate amount so that the easement is totally contained on the property that contains the open channel or storm drain and not be split onto the adjacent property. This provision allows construction of fences at the property line. All easements, shall connect to public access points. Easements shall be wide enough, and shall be located to allow convenient access for inspection and repairs, regardless of the minimum widths given herein. 3.2 Drainage Easements Public drainage easements giving the County or a public entity such as VDOT the right to discharge stormwater runoff onto private property is required for all public storm drainage systems and BMPs that are located on private property. This includes open channels, culverts, inlets, storm drains, stormwater management basins, and other best management practices that are owned, operated, and maintained by the County or other public entity such as VDOT. COUNTY OF ROANOKE EASEMENTS ^//14 x/1/16 3-1 EASEMENTS CHAPTER 3 Public storm drainage systems are used to convey stormwater drainage from public property, public right-of-way, or another public storm drainage system through private property. Once the stormwater is discharged into a perennial or intermittent stream, or is otherwise managed, a public drainage easement is not required. Public BMPs are used to provide appropriate stormwater management for stormwater runoff generated by land development on public property. Examples of situations where a public drainage easement is required include: • Concentrated stormwater runoff from a County or County School Board owned site discharging to private property, including any open channels leaving the property or any storm drains leaving the property. • Concentrated stormwater runoff from public streets and open channels or storm drains from the public street right-of-way which passes onto any private property. Private drainage easements giving a private party the right to discharge concentrated stormwater runoff onto downstream private property is required whenever connection is made to a downstream private storm drainage system. No buildings, foundations, structures, fences or walls, not associated with the storm drainage system or BMP shall be located within a drainage easement. In addition, easements that contain open channels shall not be obstructed by fences or unmanaged vegetation. The closest edge of a storm drainage easement shall not be located within 10 feet of the rear wall of any individual single-family residential structure, except where the easement is required to access a BMP that is solely serving the single-family residence. Underground utility lines and structures shall be kept at least 5 -feet horizontal from drainage pipes, structures, and channels, except at utility crossings. Utility crossings at drainage easements shall be at as near 90-degress as possible. Where a storm drainage system terminates or starts short of a property line, adequate drainage easements shall be dedicated to allow for maintenance and future extension of the system through the property. 3.2.1 Culverts and Storm Drains The minimum width of drainage easements for culverts and storm drains shall be as follows: Pipe Size (width) Minimum Easement Width # Smaller than 36" 20 feet 36" — 42" 25 feet 48" — 60" 30 feet COUNTY OF ROANOKE EASEMENTS ^//14 x/1/16 3-2 EASEMENTS CHAPTER 3 66" — 78" 35 feet `Minimum width given above is for installations with depths of cover of 10 -feet orI Formatted: Font: Bold less (measured at the top of pipe). For each additional 5 -feet of cover over 10 -feet (rounded up), the minimum easement width shall be increased by 10 -feet. for pipes that are larger than given in the table above, and for installations that , - Formatted: Font: Bold result in minimum easement widths greater than 50 -feet due to installation depths, the minimum easement width shall be set by the County based on the width requirements to access the pipe in the future for repair. Drainage easements at the inlet and outlet of all culverts and storm drain inlets shall include the areas inundated by the headwater during the 100 -year storm. The easement shall extend a minimum of 10 feet from culvert inlets and outlets and storm drain inlets to allow for maintenance access. Where steep slopes and/or deep fills exist, additional easement area may be required to allow for proper access. Storm drain easements shall cross private driveways at perpendicular angles to the extent practical. 3.2.2 Open Channels The minimum width of the drainage easement required is dependent on the top width of the channel as indicated in Figure 3-1. The County may require wider easement width, if the open channel is located in rough terrain and additional width is required for access for inspection or repair. COUNTY OF ROANOIKE ^//14 x/1/16 Figure 3-1 Minimum Easement Width for Open Channels 3-3 EASEMENTS EASEMENTS it CHAPTER 3 EASEMENT WIDTH ]0" - —10' TOP WIDTH OF CHANNEL DEPTH OF PROPOSED CHANNEL PROPOSED CHANNEL WIDTH OF BO TT OM 3.3 Access Easements Access easements giving the County the right to access private property for the purpose of inspecting, and if necessary to maintain or repair private BMPs is required for all private BMPs. This includes stormwater management basins, filter strips, bioretention trenches, underground detention areas, and all other BMP's. All structures, pond areas, embankments, inlet and outlet channels, and access and working areas necessary to inspect, maintain, and repair the facilities shall be included in access easements. The 100 -year flooding area of all stormwater basins or other holding structures shall be contained within the access easement area. In addition, all BMPs shall contain a minimum 20 -foot working area around all stormwater management basins and a minimum 10 -foot working area around all other BMPs and an access easement connecting to a public road. Depending on the size and location of the stormwater management facility, more than one vehicle accessible access easement connecting to a public road may be required. All stormwater structures and BMPs shall be accessible by vehicle. Areas within an access easement that are intended to be vehicle accessible shall have a maximum slope of 10 percent for unpaved surfaces and 18 percent for paved surfaces. The vehicle access shall be a minimum of 12 feet in width. The minimum width for an access easement shall be 20 feet. All access easements shall connect to a public road or right of way; unless a suitable blanket access easement is provided. 3.4 Maintenance of Easements COUNTY OF ROANOKE EASEMENTS 74/14-x/1/16 3-4 EASEMENTS CHAPTER 3 Ownership of land within easements shall remain with the property owner. The property owner shall have the responsibility of maintaining the easement areas free of any obstructions or use that would interfere with the rights or privileges granted by the property owner. The property owner shall not alter the existing ground elevations or in any way redirect or obstruct stormwater flow. Any alterations to easements resulting in obstruction or redirection of flow will be returned to existing elevations immediately at the cost of the property owner. COUNTY OF ROANOKE ^//14 x/1/16 3-5 EASEMENTS EASEMENTS APPENDIX 3A STANDARD EASEMENT AGREEMENTS County of Roanoke — Permanent Drainage Easement Agreement COUNTY OF ROANOKE ^//14 x/1/16 3A-1 APPENDIX 3A EASEMENTS EASEMENTS APPENDIX 3A Exemption Claimed: Grantee is exempted from recordation taxes and fees pursuant to § 58.1- 811A(3), Code of Virginia. Prepared By: Tax Map No.: Property Owners: THIS DEED OF EASEMENT, made this and between AND day of 20 , by whether one or more, "Grantor") and the BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA ("Grantee"). WITNESSETH: That for and in consideration of the sum of One Dollar ($1.00), paid in hand at and with the execution and delivery of this Deed of Easement, and other good and valuable consideration, the receipt, adequacy and sufficiency of which is hereby acknowledged, the Grantor does hereby GRANT and CONVEY with General Warranty and Modern English Covenants of Title unto the Grantee, its successors and assigns, the following described easement, to -wit: A perpetual RIGHT and EASEMENT, approximately feet in width, to construct, operate, maintain, inspect and repair or replace a drainage system and related improvements including slope(s), if applicable, together with the right of ingress and egress thereto from a public road, upon, over, under, and across a tract or parcel of land belonging to the Grantor, acquired by deed dated and recorded in the Clerk's Office of the Circuit Court of Roanoke County, Virginia, in Deed Book , page , and designated on the Roanoke County Land Records as Tax Map No. (the "Property"). The location of said easement is more particularly described on the plat attached hereto as "Exhibit A" and by this reference made a part hereof (the "Plat"), and shown traversing as shown on Exhibit A. The Grantee agrees to restore and repair any actual damage to Grantor's Property which may be directly caused by the construction, reconstruction, or maintenance of said project except as hereinafter provided. The Grantor agrees that the Grantee will not be expected to restore the Property to the identical original condition, but rather as near thereto as is practicable, and that the Grantor will cooperate with the Grantee in effectuating such restoration. It is expressly agreed between the parties hereto that the Grantee and its agents shall have the right to inspect the easement herein granted and to cut, clear, and remove all undergrowth, obstructions, or improvements lying within or upon-a�jaee to said easement, that in any way endanger or interfere with the proper use of the same. The Grantor covenants that no building or structure shall be erected upon or within the easement herein granted or placed in such location as to render the said easement inaccessible. In the event that this covenant is COUNTY OF ROANOKE EASEMENTS ^//14 x/1/16 3A-2 EASEMENTS APPENDIX 3A violated, the Grantee shall not be obligated to repair, replace, or otherwise be responsible for such improvements if damaged or removed. The Grantor acknowledges that the plans for the aforesaid project as they affect the Property have been fully explained to the Grantor or Grantor's authorized representative. The fixtures, facilities, lines, utilities, and any other improvements placed upon, under, or across the Property by the Grantee shall remain the property of the Grantee. The easement herein granted is in addition to, and not in lieu of, any easement or right-of-way now in existence or which may be acquired in the future. The Grantor covenants and aggress for themselves, and for their heirs, successors, successors in title, executors, legal representatives, and assigns that the consideration aforementioned and the covenants herein shall be in lieu of any and all claims to compensation and damages by reason of the location, construction, operation, maintenance, or reconstruction of or within the easement herein granted. The grant and provision of this Deed of Easement shall constitute a covenant running with the land for the benefit of the Grantee, its successors and assigns forever to have and hold unto the Grantee, its successors and assigns forever. , County Administrator, or his designee, of Roanoke County, Virginia, hereby joins in the execution of this instrument to signify the acceptance by said Board of Supervisors of the real estate conveyed herein pursuant to Ordinance No. adopted by the Board of Supervisors of Roanoke County, Virginia, on the day of IN WITNESS WHEREOF, the parties hereto have caused this agreement to be executed on their behalf. GRANTOR: (SEAL) (SEAL) (Name) (Name) GRANTOR ACKNOWLEDGMENT COUNTY OF ROANOKE EASEMENTS ^//14 x/1/16 3A-3 EASEMENTS APPENDIX 3A State of - Count -,,/City of: to wit: The foregoing instrument was acknowledged before me this day of and (Notary Public Signature) (Notary Public Printed Name) My Commission expires: Registration # BOARD OF SUPERVISORS OF ROANOKE COUNTY. VIRGINIA: (SEAL) (County Administrator of Roanoke County, Virginia) COUNTY ACKNOWLEDGMENT State of- County/City of: , to wit: The foregoing instrument was acknowledged before me this day of by , County Administrator, on behalf of the Board of Supervisors of Roanoke County, Virginia. (Notary Public Signature) (Notary Public Printed Name) My Commission expires: Registration # COUNTY OF ROANOKE 74/14—x/1/16 3A-4 (SEAL) EASEMENTS STORMWATER HYDROLOGY Chapter 4 - Stormwater Hydrology CHAPTER 4 Stormwater hydrology defines the means and methods to calculating stormwater runoff from a designated area. This section documents the hydrologic practices used to establish design flows necessary to prepare the required stormwater peak flow and storage calculations. 4.1 References Except where more stringent requirements are presented in this Design Manual, stormwater hydrology shall comply with state requirements. The primary design references are: • VDOT Drainage Manual • VA SWM Handbook • BMP Clearinghouse 4.2 Design Frequencies 4.2.1 General Design frequencies shall be selected consistent with good engineering practice and economics. The design frequency requirements given in this Design Manual are minimum, specific conditions may dictate that less frequent design frequency should be used. 4.2.2 Storm Drainage Systems Storm drainage systems consist of manmade open channels, culverts, and storm drains. Designs shall be based on the following minimum design storm frequencies: Manmade Open Channels: , - Formatted: Underline Minor Channel Capacity 10 -year Minor Channel Protective Lining (Drainage Area 5 acres or less) 2 -year Minor Channel Protective Lining (Drainage Area over 5 acres) 10 -year Major Channel Capacity 100 -year Major Channel Protective Lining 10 -year (100 -year if potential for catastrophic failure) Culverts: - - Formatted: Underline Principal Arterial Roads 25 -year COUNTY OF ROANOKE 7444X/1/16 4-1 STORMWATER HYDROLOGY STORMWATER HYDROLOGY Other Roads CHAPTER 4 10 -year Storm Drains 10 -year - - I Formatted: Underline All storm drainage designs for open channels, culverts, and storm drains shall be checked for the 100 -year flow condition where there is the possibility of flooding residences, commercial or industrial buildings, overtopping primary roads, experiencing significant economic loss, or catastrophic failure. Where justified by the consequences of failure, the minimum design frequency shall be increased. 4.2.3 Stormwater Management Facilities Designs shall be in accordance with the VA SWM Handbook and BMP Clearinghouse. 4.3 Time of Concentration (t�) and Travel Time (Tt) 4.3.1 General Time of Concentration (Q is the length of time required for a drop of water to travel from the most hydraulically distant point in the watershed, or subwatershed to the point of analysis. Travel Time (T) is the length of time required for that same drop of water to travel from the study point at the bottom of the sub - watershed to the study point at the bottom of the whole watershed. The travel time is descriptive of the sub -watershed by providing its location relative to the study point of the entire watershed. Therefore Time of Concentration is the summation of Travel Time values for the various consecutive flow segments. Travel Time and Time of Concentration generally consist of four flow types - overland flow, shallow concentrated flow, channelized flow, and pipe systems. Calculations shall be reviewed for reasonableness and the results shall be revised if needed to provide a reasonable velocity and flow time that will best represent the study area. When designing a drainage system, the flow path is not necessarily the same before and after land disturbing activities have been completed. Therefore, the travel time path shall be reflective of the actual conditions both before and after the land disturbing activities. In some cases, runoff from a portion of the drainage area that is highly impervious may result in a greater peak discharge than would occur if the entire area were considered. In this case, adjustments can be made to the drainage area by disregarding those areas where flow time is too slow to add to the peak discharge. COUNTY OF ROANOKE 7444X/1/16 4-2 STORMWATER HYDROLOGY STORMWATER HYDROLOGY CHAPTER 4 To prevent small drainage areas from skewing the time of concentration calculation results, when establishing sub drainage areas for analysis, the largest sub drainage area shall be no greater than 5 times the area of the smallest sub drainage area. Time of concentration maps shall include segment lengths, elevations at beginning and end of segment, slopes, and flow types. 4.3.2 Overland Flow Overland flow is flow that occurs at the upper end of a watershed, where flow is not concentrated and there are no channels. The length of overland flow shall be reflective of actual conditions and shall normally be po greater than 150 feet-------- Formatted: Underline Where the overland flow does not contain any slopes exceeding 5% AND if the soils are not designated as highly erodible, a maximum length of overland flow of 200 feet may be used. Highly erodible soils are designated as United States Department of Agriculture Natural Resources Conservation Service land capability classification (LCC) classes IIIe, IVe, VI, VII, or VIII or having an erodibility index greater than or equal to 8.—Overland flow shall be calculated using the Seelye chart contained in the Appendix 4A for the Rational Method or TR -55 for the SCS Method. Roughness coefficients (Manning's n) for sheet flow can be found in the TR -55 Manual. 4.3.3 Shallow Concentrated Flow Shallow concentrated flow is the flow that occurs when minor rivulets form just downstream from the overland flow. The maximum allowable length for shallow concentrated flow shall be 1000 feet. Shallow concentrated flow shall be calculated using the Overland Flow Velocity - - Formatted: indent: Left: r', First line: 0" Chart from HEC -19 or by using the nomograph entitled "Time of Concentration of Small Drainage Basins," developed by P.Z. Kirpich. Copies of the Kirpich chart and nomograph are contained in Appendix 4A and shall be used for the Rational Method. TR -55 shall be used for the SCS Method. Results from the Kirpich nomograph shall be multiplied by 0.2 for paved channels. 4.3.4 Channelized Flow Channelized flow occurs where stormwater flow converges in gullies, ditches, and natural or man-made water conveyances, including storm drain pipes and culverts. Channelized flow shall be calculated by use of the nomograph entitled "Time of Concentration of Small Drainage Basins," developed by P.Z. Kirpich. A copy of the nomograph is contained in Appendix 4A and shall be used for the Rational COUNTY OF ROANOKE 7444X/1/16 4-3 STORMWATER HYDROLOGY STORMWATER HYDROLOGY CHAPTER 4 Method. TR -55 shall be used for the SCS Method. Results from Kirpich nomographs shall be multiplied by 0.2 for paved channels. 4.3.5 Pipe Flow Pipe flow is the flow that occurs through culverts and storm drains. Use full -flow pipe velocities, unless it may be demonstrated that the pipe will operate at partial full conditions. If it can be shown that the pipe will operate at partial full conditions, then the partial full pipe velocity may be used. Design of flow through culverts is presented in Chapter 6. Design of flow in storm drain systems is presented in Chapter 7. 4.4 Selection of Methodologies 4.4.1 General There are a variety of widely used hydrologic methodologies. Each has its strengths and weaknesses. In the interest of standardizing hydrologic calculations, the following methodologies will be used for all projects, unless the County agrees that good engineering practice dictates the use of another method. 4.4.2 Peak Discharge Methods for Design of Storm Drainage Systems The fAiena4-Rational +netl}ed-Method may be used to design storm drainage conveyance systems for drainage areas up to 200 acres. Minimum time of concentration when using the Rational Method is 5 minutes. The SCS method may be used for drainage areas up to 10 square miles. For drainage areas greater than 10 square miles, calculations shall be performed using at least two separate methods as described in the VDOT Drainage Manual (SCS method, regression equations, and/or stream gage data). The design peak flow shall be selected based on a professional evaluation of the results of the various methods. 4.4.3 Hydrograph Methods for Design of Stormwater Management Facilities COUNTY OF ROANOKE 7444X/1/16 4-4 STORMWATER HYDROLOGY STORMWATER HYDROLOGY CHAPTER 4 The SCS method may be used iii all eases. The SCS ffle�had fffd4 be used whefe miffi4es of shall be used in the design of stormwater BMPs and ponds. Minimum time of concentration when using the SCS method is 6 minutes. 4.5 Methodologies Following is an abbreviated discussion of each method. Refer to the VDOT Drainage Manual and the VA SWM Handbook for a more complete discussion. 4.5.1 Rational Method �1. General ------------------------------------------- Formatted: Font: Bold The Rational Method is expressed as: Q=CMA Where: Q = Peak flow rate of runoff, cubic feet per second (cfs) f= Saturation factor -------------------------------- Commented[AG1]: C = Runoff coefficient representing a ratio of runoff to rainfall (dimensionless) I = Average rainfall intensity for a duration equal to the time of concentration for a selected return period, inches per hour (in/hr) A = Drainage area contributing to the design location, acres (ac) B. Saturation Factor ........ Formatted: Font: Bold The saturation factor (Cf) is an adjustment factor for modifying the runoff coefficient (C) for storms that are less frequent than a 10 -year recurrence interval. The product of Cf and C should not be greater than 1.0. - - Formatted: Indent: Left: 1.44", First line: 0.25" Recurrence Interval (Years) Cf 2, 5, and 10 1.0 25 1.1 50 1.2 100 1.25 Where the product of Cf and C is greater than 1. 0, use 1.0. C. )2unoff Coefficient Formatted: Font: Bold COUNTY OF ROANOKE 7444X/1/16 4-5 STORMWATER HYDROLOGY STORMWATER HYDROLOGY CHAPTER 4 The runoff coefficient (C) is a variable of the Rational Method that requires significant judgment and understanding for proper selection. A range of C - values for a given land use is given in Appendix 4A. The coefficient must account for all the factors affecting the relation of peak flow to average rainfall intensity other than area adjustment. Some of these factors include land slope, condition of cover, and antecedent moisture condition. As the slope of the drainage basin increases, the selected C -value should also increase. The lower range of C -values should be used where the majority of the slopes are less than 2 -percent. The average range of C -values should be used where the majority of slopes are 2 to 5 -percent. The higher range of C - values should be used where the majority of the slopes are greater than 5 - percent. The higher range of C -values should be used in clayey and other less pervious soil areas. D. Average Rainfall Intensity See the VA SWM Handbook. An IDF curve file is located on the Roanoke County webpage for use with HydroCAD and Hydraflow at �ttp://www.roanokecopptyva_gov/index.aspx?NID=317- Q factors are not , - Field Code Changed included for 025 and Qioo in the IDF files and should be accounted for the , - Formatted: Not Highlight calculations. JE._ Drainage Area Formatted: Font: Bold Drainage area (DA) is measured in acres and is determined from evaluating a topographic map of the area. 4.5.2 Modified Rational Method COUNTY OF ROANOKE 7444X/1/16 4-6 STORMWATER HYDROLOGY STORMWATER HYDROLOGY CHAPTER 4 �1. General ------------------------------------------- Formatted: Font: Bold The Modified Rational Method is a means to generate hydrographs for small drainage areas. The parameters for the calculation are the same as the Rational Method, except that a series of average rainfall intensities from different storms with the same frequency and different durations are computed. The hydrograph from the critical duration storm is used to design stormwater management facilities. The Modified Rational Method recognizes that the duration of a storm is often longer than the time of concentration. This longer duration storm, even though it produces a lower peak Q, can produce a larger volume of runoff than the storm duration equal to the actual time of concentration of the drainage area. In order to ensure the proper design of stormwater management facilities, the runoff for the critical storm duration shall be used. —B. Hydrograph Assumptions Formatted: Font: Bold The hydrograph generated by the Modified Rational Method is based on the following assumptions: • Time of Concentration (Q = Time to Peak (Tp) = Time to Recede (Tr) • The length of the critical duration storm (De) is from 0 minutes until the time of selected duration. • The rate of runoff is 0 at time 0 minutes. The rate of runoff increases linearly with time until the peak rate of runoff is reached at time Tp. • The peak rate of runoff is maintained from time Tp until the duration of the storm (De). The rate of runoff then decreases to 0 at time De plus Tr. • The peak rate of runoff is based on the average rainfall intensity (I) for the given storm duration. C._ Critical Duration Storm Formatted: Font: Bold The critical duration storm is the storm of a given frequency that has a duration that yields the greatest volume of storage in a stormwater management facility when the storm hydrograph is routed through the stormwater management facility. The critical duration storm may be estimated for preliminary purposes; however, the actual critical duration COUNTY OF ROANOKE 7/4/14x/1/16 4-7 STORMWATER HYDROLOGY STORMWATER HYDROLOGY CHAPTER 4 storm must be determined by routing the various duration storm hydrographs through the stormwater management facility and demonstrating which storm duration gives the greatest volume of storage. 4.5.3 SCS Method A. General ------------------------------------------- Formatted: Font: Bold The SCS Method may be used for computing peak flows and hydrographs for storms of selected return frequencies. This approach considers the time distribution of the rainfall, the initial rainfall losses to interception and depression storage and an infiltration rate that decreases during the course of a storm. The information required to use the SCS Method to determine the peak rate of runoff, or to develop a runoff hydrograph is: • 24-hour total rainfall, and rainfall distribution type. The 24 hour precipitation rate is based upon NOAA values at the Roanoke Airport. These values can be found on Roanoke County's website or NOAA's website. • Time of Concentration (Q in minutes, rounded up to the nearest whole minute; • Curve Number (CN), which is determined by Cover Types and Hydrologic Soils Groups; and • Drainage Area (A) in acres. If the drainage basin is over 20 acres, or if it contains areas of different land - - Formatted: indent: Left: 1.25", First line: o" uses, the drainage basin should be divided into sub -basins. Each sub -basin should have similar land uses. When sub -basins are used, the following information is required to use the SCS Method to determine the peak rate of runoff, or to develop a runoff hydrograph: • 24-hour total rainfall, and rainfall distribution type. The 24 hour precipitation rate is based upon NOAA values at the Roanoke Airport. • Time of Concentration (Q in minutes for each sub -basin, rounded up to the nearest whole minute; • Curve Number (CN), which is determined by Cover Types and Hydrologic Soils Groups, for each sub -basin; • Drainage Area (A) in acres, for each sub -basin; and COUNTY OF ROANOKE 7444X/1/16 4-8 STORMWATER HYDROLOGY STORMWATER HYDROLOGY CHAPTER 4 Travel Time (Tt) of the flow from each sub -basin as it flows through downstream sub -basins. If the SCS Method is being used to design a stormwater management facility, the following additional information is required to rout the runoff hydrograph through the facility and to generate an outflow hydrograph: • Elevation — Storage Relationship • Elevation — Discharge Relationship B. �4-hour Rainfall and Distribution - " " I Formatted: Font: Bold The 24-hour rainfall is determined by fir..f f«,.,,..,...,.., 1,.,.. ted 4 A....,.44,7:., AB T-4 4:ni44411 d is4*ib..r:,.., rYpe f ,. Oh-@ n,.,.HR-ke 378 -1 -lay is -r.,.., Ti NOAA precipitation amounts for Roanoke Airport. C. Curve Number------------------------------------ --" Formatted: Font: Bold The SCS method uses a combination of soil conditions and land use (ground cover) to assign a runoff factor to an area. These runoff factors, or runoff curve numbers (CN), indicate the runoff potential of an area. The CN requires significant judgment and understanding for proper selection. A table containing CNs for various cover types and soils conditions is contained in Appendix 444A. When calculating existing rates of runoff (pre -construction), assume that all cover types are in good hydrologic condition. Hydrologic Soils Groups (HSG) include types A, B, C, and D, with type A being the most permeable and type D the least permeable. Appendix 4B includes a listing of most soil names with their respective hydrologic soils types. Urban/udorthents soils shall be considered a Type D soil for design purposes. Soils maps for the Roanoke Valley may be obtained by referring to USDA web soil survey. Colored soil maps with support HSG documentation shall be included in the calculations packet D. Prainage Area - Formatted: Font: Bold COUNTY OF ROANOKE 7444X/1/16 4-9 STORMWATER HYDROLOGY STORMWATER HYDROLOGY CHAPTER 4 Drainage areas for each sub -basin should be identified on an appropriate topographic map. E. _Elevation — Storage Relationship _ Formatted: Font: Bold When runoff hydrographs are being routed through a stormwater management facility, the relationship between the elevation (or depth) of stored water in the facility and storage volume needs to be known and input into the calculation. Often this information is obtained by determining the pond area bounded by contour lines on a grading plan. Enough data pairs (elevation — storage) must be provided to properly model conditions at transition points. F. _Elevation — Discharge Relationship ...... ------------ Formatted: Font: Bold When runoff hydrographs are being routed through a stormwater management facility, the relationship between the elevation (or depth) of stored water in the facility and the discharge flow rate from the facility needs to be known and input into the calculation. The development of this relationship requires an understanding of the design conditions and underlying hydraulic principles. The hydraulic principals and equations governing the discharge rate will often change several times at varying elevations. These include weir flow, orifice flow, culvert inlet control, culvert outlet control, open channel flow, and possible effects from downstream backwater. 4.7 Drainage Area Analysis To prevent the undersizing of stormwater management components, upstream properties conditions shall be considered in the drainage area analysis. Stream channel and improvements to any conveyance system shall be analyzed. When a project site contains or is divided by multiple drainage areas, stormwater - - Formatted: indent: Left: r', First line: o" management of each drainage area must be addressed separately. Over detention of one flow is not an effective solution to achieving water quantity goals. Improving the channel immediately downstream is not effective in controlling the actual flow release from the site beingdeveloped, nor does it reduce the impact of the flow on properties further downstream. COUNTY OF ROANOKE 7444X/1/16 4-10 STORMWATER HYDROLOGY STORMWATER HYDROLOGY APPENDIX 4A DESIGN AIDS FROM CHAPTER 6, VDOT DRAINAGE MANUAL Overland Flow Nomagraph — Seelye Overland Flow Velocity Time of Concentration for Small Drainage Basins — Kirpich Average Velocities for Estimating Travel Time for Shallow Concentrated Flow Rational Method Runoff Coefficients Runoff Curve Numbers for Urban Areas Runoff Curve Numbers for Cultivated Agricultural Areas Runoff Curve Numbers for Other Agricultural Areas COUNTY OF ROANOKE 7444X/1/16 4A-1 APPENDIX 4A STORMWATER HYDROLOGY STORMWATER HYDROLOGY nVFBT . A Nil Fl .nW - 4ZFF7 .VF APPENDIX 4A RURWTED WJTN P€:RWISSION FROM 'DATA BOOB FOR CIVIL ENGINEERS` VOL. I-aESIGN Esm EOLTION (19511 BY €.E.SEELYE COUNTY OF ROANOKE 7444s/1/16 STORMWATER HYDROLOGY 4A-2 900 35- 800 T� = 0:2251-0.42 S-o.i�) C-I.o 700 600 T, -Overland Flow Time, minutes 30 L=Length of Strip, feet 500 Paves S=Slope, foot/foot C=Rational "C" Value 400 0.8 1 25- 304 O.i 0.6 dare $oil 0.5 20 a 200 Poor 0.4 Grass Surface-- s�4 LU L Gross p+Vera -Q.3 a 0.5 Uj Z l 00 Sur#aae `- -- 1.0 IL 15- 90 A c) �7- a ` I1► a so Dense - . z FL Grass 0.2 60 LL 5 O z 20 ,s a 40 o 30 LL- iQ Q Uj LE4 ¢ z z a ct e� 7, z c� 10 6 - OVERLAND FLOW TIME RURWTED WJTN P€:RWISSION FROM 'DATA BOOB FOR CIVIL ENGINEERS` VOL. I-aESIGN Esm EOLTION (19511 BY €.E.SEELYE COUNTY OF ROANOKE 7444s/1/16 STORMWATER HYDROLOGY 4A-2 STORMWATER HYDROLOGY APPENDIX 4A OVERLAND FLOW VELOCITY .1 2 3 5 1 Y 3 S Io z4 50 so C,f w 3 Id tLb IL O if7 S Ld co W � g 1 74444xnn6 2 .3 .3 1 2 s 5 VELOCITY, Y ( FT I SEC) 4A-3 Si] 30 20 -j5 90 STORMWATER HYDROLOGY STORMWATER HYDROLOGY APPENDIX 4A TIME OF CONCENTRATION - KIRPICH (Note: MultiDly Tc by 0.2 for Paved Channels) Tc = 13.03948 B-039 X1.13 '% - P AV11M£, MIMES 30 - lim6im rEef L - 1.FkVrR.FEE TIME nF EONCENTRATIDN OF SMALL DRAINAGE BASINS COUNTY OF ROANOKE 7/1444/1/16 4A-4 STORMWATER HYDROLOGY Soo EXAMPLE Tc (MW 4a@ HEffinr - 14113 FT. 2014 - LENUTF!3 MMIA €T. rimE up cmCcNTRATT[]11 = i+ KjM- 158 200 100 150 Fa PA -lag 613 x a o 40 58 50901 3a 4.0 Z: 3o 3� @! 25 e w 1 zaP�Pl9; 1000 l0 � Sip 5 5 4 4 s 3E�J 290 15� 2 � x Ilvrd aei ' by P X Yurine st iFnF €nrd csr.ni*WV&_ h0 Nu. 6. Jux 1940. 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The lowest range of runoff coefficients may be used for flat areas (areas where the majority of the grades and slopes are 2% and less). 2. The average range of runoff coefficients should be used for intermediate areas (areas where the majority of the grades and slopes are from 2% to 5%). 3. The highest range of runoff coefficients shall be used for steep areas (areas where the majority of the grades are greater than 5%), for cluster areas, and for development in clay soil areas. 4. The residential runoff coefficients include impervious and pervious amounts in the coefficient. * Lower runoff coefficients should be used for permanent or established conditions (post - construction), i.e. sizing stormwater management basins. * Higher runoff coefficients should be used to design roadside ditch linings (construction). The design considers the ditch lining as not yet established. - - - Formatted Table Formatted: Font: 11 pt ** Based upon Manufacturer's recommendation and BMP Clearinghouse specifications. - I Formatted: Font: 12 pt COUNTY OF ROANOKE 7444X/1/16 4A-6 STORMWATER HYDROLOGY STORMWATER HYDROLOGY RUNOFF CURVE NUMBERS FOR URBAN AREAS APPENDIX 4A COUNTY OF ROANOKE 7444X/1/16 4A-7 STORMWATER HYDROLOGY Soil Group A B C D Cover type and hydrologic condition Open space (lawns, parks, golf courses, cemeteries): Poor condition (grass cover < 50%) 68 79 86 89 Fair condition (grass cover 50% to 75%) 49 69 79 84 Good condition (grass cover > 75%) 39 61 74 80 Impervious areas: Paved parking lots, roofs, driveways (excluding right-of-way) 98 98 98 98 Streets and roads: Paved; curbs and storm drains (excluding right-of-way) 98 98 98 98 Paved; open ditches (including right-of-way) 83 89 92 93 Gravel (including right-of-way) 76 85 89 91 Dirt (including right-of-way) 72 82 87 89 Urban districts: Commercial and business (85% average impervious area) 89 92 94 95 Industrial (72% average impervious area) 81 88 91 93 Residential districts by average lot size: 0.10 or less, town houses (65% average impervious area) 77 85 90 92 '/4 acre (38% average impervious area) 61 75 83 87 1/3 acre (30% average impervious area) 57 72 81 86 'h acre (25% average impervious area) 54 70 80 85 1 acre (20% average impervious area) 51 68 79 84 2 acre (12% average impervious area) 46 65 77 82 Developing urban areas: Newly graded areas(pervious areas only, no vegetation) 77 86 91 94 COUNTY OF ROANOKE 7444X/1/16 4A-7 STORMWATER HYDROLOGY STORMWATER HYDROLOGY RUNOFF CURVE NUMBERS FOR CULTIVATED AGRICULTURAL AREAS APPENDIX 4A Cover Treatment Hydrologic Soil Group A B C D type condition Fallow Bare soil --- 77 86 91 94 Crop residue Poor 76 85 90 93 Cover (CR) Good 74 83 88 90 Row Crops Straight Row (SR) Poor 72 81 88 91 Good 67 78 85 89 SR and CR Poor 71 80 87 90 Good 64 75 82 85 Contoured (C) Poor 70 79 84 88 Good 65 75 82 86 C and CR Poor 69 78 83 87 Good 64 74 81 85 Contoured & Terraced Poor 66 74 80 82 (C & T) Good 62 71 78 81 C&T and CR Poor 65 73 79 81 Good 61 70 77 80 Small Grain SR Poor 65 76 84 88 Good 63 75 83 87 SR and CR Poor 64 75 83 86 Good 60 72 80 84 C Poor 63 74 82 85 Good 61 73 81 84 C and CR Poor 62 73 81 84 Good 60 72 80 83 C&T Poor 61 72 79 82 Good 59 70 78 81 C&T and CR Poor 60 71 78 81 Good 58 69 77 80 Close -seeded SR Poor 66 77 85 89 or broadcast Good 58 72 81 85 Legumes or C Poor 64 75 83 85 rotation Good 55 69 78 83 Meadow C&T Poor 63 73 80 83 Good 1 51 67 76 80 Comments: Crop residue cover (CR) applies only if residue is on at least 5% of the surface throughout the year. Poor = Factors impair infiltration and tend to increase runoff Good = Factors encourage average and better than average infiltration and tend to decrease runoff. COUNTY OFROANOKE 74/14x/1/16 4A-8 STORMWATER HYDROLOGY STORMWATER HYDROLOGY RUNOFF CURVE NUMBERS FOR OTHER AGRICULTURAL AREAS C'.nmmPntc- APPENDIX 4A Cover Hydrologic Soil Group A B C D type condition Pasture', grassland, or range- Poor 68 79 86 89 continuous forage for grazing Fair 49 69 79 84 Good 39 61 74 80 Meadow — continuous grass, 30 58 71 78 protected from grazing and generally mowed for hay BrusW — brush -weed -grass mixture Poor 48 67 77 83 with brush as the major element Fair 35 56 70 77 Good 30 48 65 73 Woods — grass combination Poor 57 73 82 86 (orchard or tree farm) Fair 43 65 76 82 Good 32 58 72 79 Woods Poor 45 66 77 83 Fair 36 60 73 79 Good 30 55 70 77 Farmsteads — buildings, lanes, 59 74 92 86 driveways, and surrounding lots PasturePoor < 50% ground cover or heavily grazed with no mulch Fair 50% to 75% ground cover and not heavily grazed Good > 75% ground cover and lightly or only occasionally grazed Brush Poor < 50% ground cover Fair 50% to 75% ground cover Good > 75% ground cover Woods Poor — Forest litter, small trees and brush are destroyed by heavy grazing or regular burning Fair — Woods grazed but not burned, and some forest litter covers the soil Good — Woods protected from grazing, litter and brush adequately cover soil COUNTY OF ROANOKE 7444X/1/16 4A-9 STORMWATER HYDROLOGY STORMWATER HYDROLOGY APPENDIX 4B APPENDIX 4B DESIGN AIDS FROM CHAPTER 4, VA SWM HANDBOOK Rational Equation Coefficients for SCS Hydrological Soil Groups, Urban Land Uses Rational Equation Coefficients for SCS Hydrological Soil Groups, Rural and Agricultural Uses Roughness Coefficient "n" for Manning Equation — Sheet Flow Roughness Coefficient "n" for Manning Equation — Pipe Flow Roughness Coefficient "n" for Manning Equation — Constructed Channels Roughness Coefficient "n" for Manning Equation—Natural Stream Channels Hydrologic Soils Names in Virginia (7 sheets) COUNTY OF ROANOKE ^//1�t4X/1/15 4B-1 STORMWATER HYDROLOGY + O OO O N N O O, l— V) 0 0 0 0 0 O o 0 0 �o,ry�o�m mmmry cgo0o00 0000 0000,c�m 000�ov c�a,ry�o�m mryryry A o 0 0 0 0 0 0 0 0 0 +Ovo,cgoo �o�tN� 0 o�ry�o�m mmmm 10 O O o 0 Cl 0 0 0 0 o O moo,-�o�m mc�c�c� c500000 0000 o O�t 00 N0 l- v1 N 0 co m NNNN U 6 0 0 0 0 0 0 0 0 0 + O a, cq V) m O oo �o oo,ry�o�m mmryry 10 O O o 0 0 0 0 Cl 0 0 0 �c 00 0 a, �o m o - o r- m cq cq cq cq Q c500000 0000 0 00�N 'r\ioo- NN° — p W o 0 0 0 0 0 0 0 0 0 0 C7 +o noocq a,rovc c`!c`!c`!c`!q o 'o o 0 0 0 0 0 0 0 0 u o moo,-��N NNN� o c500000 0000 0 �^o oOoor- cqo, o� coo O or�ry ry x 0 0 0 0 0 0 0 0 0 0 w � u N O o a w IO o CIO w � z a W cd m Cd occ �� �00000 a P. °ciwaaaaa I W i + 00 0 o o M M ry ry o �o �o r- �o �o 0 o n 0 0 0 0 0 0 0 0 0 O o 0 0 0 0 c5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 A O O O O O O O O O O O O O O O +� ooN�NooM- N- O 0 0, W 't 'o O O O O O O O O O O O O O O o a 00 W)0,00 00000 0000r - N N r� W� -t W� -zt Wi V -zt c5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o l� V N O N--� N N N— — -- W) V v, vi V U o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 + 10 0 0 0 0 0 0 0 0 0 0 0 0 0 0 vl N �oN -��o�� : m AM m M M M M MM 0000000 000 000 0 N� -� o�ov�M AMM MMry p 0 W o 6 6 0 0 0 0 0 0 0 0 0 0 0 0 C7 + M vi o 0 0 0� M M ry ry ry ry ry ry 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 goo 000vMryry ryryry o c5o 0000000 000 000 s°. N o 0 0 0� ry ry ry ry o W •o � kna� ^a N x °u o C7 0 C7 0 C7 0 C7 0 C7 0 C7 0 C7 0 C7 0 C7 0 C7 0 C7 0 C7 � 1 0 0 N 0 0 N 0 0� .c' co 0 0� .c' o o� o W FSA. Z U v v o 0 0 uE y v o U 0 0 UE y v o U 0 0 UE w a a foo y � 0 0 _ C o U O STORMWATER HYDROLOGY ROUGHNESS COEFFICIENT "n" FOR MANNING EQUATION - SHEET FLOW COUNTY OF ROANOKE 7444X/1/16 Surface Description n Smooth Surfaces (Concrete, 0.011 Asphalt, Gravel, or Bare Soil) Fallow (no residue) 0.05 Cultivated Soils: Residue Cover < 20% 0.06 Residue Cover > 20% 0.17 Grass: Short Grass Prairie 0.15 Dense Grasses 0.24 Bermuda Grass 0.41 Range (Natural) 0.13 Woods: Light Underbrush 0.40 Dense Underbrush 0.80 4B-4 APPENDIX 4B STORMWATER HYDROLOGY STORMWATER HYDROLOGY ROUGHNESS COEFFICIENT "n" FOR MANNING EQUATION - PIPE FLOW Material "n" Range From To Coated Cast Iron 0.010 0.014 Uncoated Cast Iron 0.011 0.015 Vitrified Sewer Pipe 0.010 0.017 Concrete Pipe 0.949013 0 01:7 Common Clay Drainage Tile 0.011 0.017 Corrugated Metal (2 2/3 x Yz) 0.023 0.026 Corrugated Metal (3x1 and 6x1) 0.026 0.029 Corrugated Metal (6x2 structural plate) 0.030 0.033 HDPE 0.012 COUNTY OF ROANOKE 7444X/1/16 4B-5 APPENDIX 4B STORMWATER HYDROLOGY STORMWATER HYDROLOGY APPENDIX 4B ROUGHNESS COEFFICIENT "n" FOR MANNING EQUATION - CONSTRUCTED CHANNEL Lining Material "n" Range From To Concrete Lined 0.012 0.016 Cement Rubble 0.017 0.025 Earth, Straight and Uniform 0.017 0.022 Rock Cuts, Smooth and Uniform 0.025 0.033 Rock Cuts, Jagged and Irregular 0.035 0.045 Winding, Sluggish Canals 0.022 0.027 Dredged Earth Channels 0.025 0.030 Canals with Rough Stony Beds, 0.025 0.035 Weeds on Earth Banks Earth Bottom, Rubble Sides 0.028 0.033 Small Grass Channels: Long Grass — 13" 0.042 Short Grass — 3" 0.034 COUNTY OF ROANOKE 7444X/1/16 4B-6 STORMWATER HYDROLOGY STORMWATER HYDROLOGY APPENDIX 4B ROUGHNESS COEFFICIENT "n" FOR MANNING EQUATION - NATURAL STREAM CHANNEL Channel Lining "n" Range From To 1. Clean, Straight Bank, Full Stage 0.025 0.030 No Rifts or Deep Pools 2. Same as #1, Some Weeds and Stones 0.030 0.035 3. Winding, Some Pools and Shoals, 0.033 0.040 Clean 4. Same as #3, Lower Stages, More 0.040 0.050 Ineffective Slope and Sections 5. Same as #3, Some Weeds and Stones 0.035 0.045 6. Same as #4, Stony Sections 0.045 0.055 7. Sluggish River Reaches, Rather 0.050 0.070 Weedy with Very Deep Pools 8. Very Reedy Reaches 0.075 0.125 COUNTY OF ROANOKE 7/4/14x/1/16 4B-7 STORMWATER HYDROLOGY STORMWATER HYDROLOGY APPENDIX 4B Sail Narnf Hydgru Safi MOM P H,, d9 A Soil .Nam Hyp. APPOMATTOX B AQUENCS D AQUULTS 17 ARAPAIOE 11II7 ARCOLk C ARGENT D ASBURN= C ASHE B ASHLAR B ASSATEAGUE A ATKINS D ATLEE C AUGUSTA C AURA J3 AUSTINVII-.LE B AXIS D AYCOCK B BACKBAY D BADIN B BAIZE D BAILEGAP B BAMA B BAYBORO D REACHES D BECKHAM B BELHAVEN D BELTSVU-LE C BELVOIR C BEM C BERMUDIAN B BERM B BIBB D BILTMORE A BIRDSBORO B BLADEN D BLAMT'ON C BLAND C BLEAKHILL C BLUEMONI* B BOHICKET 1] B+OIAC B BOLLING C BOLTON B BONNEAU A BOOKWOOD B ROTETOURT C BOURNE C BOWMANSVU.LE Bm BRADDOCK B BRADLEY C BRANDYWINE C BRECKINOCK B BREMO C BRENTSVILLE C BROADWAY B BROCKROAIi C BRUSHY B BUCHANAN C BUCKHALL B BUCKS B BUCKTON B BUBFSTAT B BUGLEY CID BUNCOMBE A BURK.ETOWN C BURROWSVILLE C CALVERTON C CALVIN c CAMOCCA AID CANEYVLLI.E C CARBO C CARDIFF B CAROLINE C CARRVALE D CARTECAY C CATASKA D CATHARPIN C CATLETT 0D CATOCTIN C CATPOINT A CAVERNS B CECIL B CHAGRIN B CHAPANOKE C COUNTY OF ROANOKE 74/14x/1/16 STORMWATER HYDROLOGY 4B-8 STORMWATER HYDROLOGY APPENDIX 4B Sail ame CHASTAIN Hxdori D 5m Name CHATUGE Hyd"p D Soil Name CHAVIES Hrdgrn S CI-IFNNEBY C CHESTER B CHEWACLA C CHICI{AHOMINY D CHLLHOWTE C CHINCOTEAGUE D CHIPLEY, C C&IISWELL D CHRISTIAN c CID C CLAPHAM* C CLEARBROOK D CLIFTON C CLUBCAF D CLYAffiR D COASTAL BEACH D CODORUS C COLFAX C COLLEEN C COLVARD B COMBS B COMUS B CONETOE A CONGAREE B COOSAW B COROLLA D CORYDON D COTACO C COURSEY C COWEE B COXIVILLE D CRAIGSVILLE p GRAVEN c CREEDMOOR C CROT€}N D CULLEN C CULPEPER C DALEVTTI.F D DANDRIDGE D DAVIDSON B DAW WOO B; D DECATUR B VARIANT DEK-ALB C DELANCO c DELOSS B/D DERROC B DILLA RD c DOGUE c DOROVAN D DOTHAN B DRAGSTDN C DRALL B DRY?OND D DUCKSTON AID DUFFIELD B DUL.LES D DUMFRIES. S DUNBAR D DUNNING D DUPLIN C DURHAM B DYKE B EBBING C EDGEHILL C EDNEDYTOWN B EDNEYVIL.LE B EDOM c ELBERT D ELIOAK C ELIOK C EL.KTON CID ELLIBER A EL.SINBORA B EMPORIA C ENDCAV C COUNTY OF ROANOKE 7444X/1/16 4B-9 STORMWATER HYDROLOGY STORMWATER HYDROLOGY APPENDIX 4B Sall Nam Elyd-tp Sail N9une Hyd4,rp 5611 Name H ydap ENON C ENOTF C ERNEST C FU13ANKS B EULONLA C EUNOLA C EVANSHAM D EVARD B EVERGREEN B EXUM G FACEVILLE B FAIRF'AX B FALLSINGTON BJD FAUGUIER C FAYWOOD C FEATHERSTONE D FISHERMAN D FLATWOODS C FLETCHER B FLUVANNA C FLtJVAQUENTS D FORESTDALE D FORK C FRANKSTOWN B FREDERICK B FRENCH C FRIPP A GAILA B GAINESBOR0 C GALESTOWN A GEORGEVILLE B GILPIN C GLADEHFLL B GLENELG B GLE1+Iyrn.?z C GLENWOOD B GOLDSBORO B GOLDSTON C GOLDVEIN C GORESVILLE' B GREENLEE B GRI3viSLEY R GRITNEY C GROSECLOSE C GROVER B GUERNSEY C GULLION C GUNSTOCK C GUYAN C GWINNETT B HAGERSTOWN C VARIENT HALEWOOD B KARTLETON B HATBORO D HAWKSBILL B RAYESVILL.E. B HAYMARKET D HAYTER B HAYWOOD B HAZEL C HAZEL C HAZELTON B HELENA C CHANNERY HER.NDON B HFWASSEE B HOADLY C HOBUCKEN D HOGELAND* C HOLLYWOOD D HUNTINGTON B RYATTSVILLE B HYDE BVD HYDRAQUENTS B INGLEDC?VE B =FL L C/D COUNTY OF ROANOKE 7444X/1/16 4B-10 STORMWATER HYDROLOGY STORMWATER HYDROLOGY APPENDIX 4B ,,%il NoXq IRONGATE ¢ B Soil Namc IUKAA Irgtm C Soil N2iLE IZAGORA Hudvrn C JACKLAND D JEDBURG C JEFFERSON B JOHNS C JOHNSTON D JUNALUSKA B KALN A B KELLY D KEMPSVILLE B I{ENANSVILLE A KENAAISVILLE c KEYPORT C V ARLANT KIIdKORA D KINSTON BJD KLEJ B KLU,IESVI LLE CJD KONNAROCK c LAIDIG C LAK_ERUR.ST A LAKELAND A LANE A D VARIANT LANSDALE B LAROQUE B LAVNES D LEAF D LEAKSVH,LE D LECK KILL B LEEDSVILLE• B LEETONIA C LEGORE LEHEW c LENOIR D LEON B D LEVY ❑ LEW B LEV4'ISBERRY 8 LIBRARY D LIGNUiki C LILY 13 LINDSIDE c LITTLETOE B LITZ c LLOYD C LOBDELL B LODI B LOUISA B LOL11SBURG B LOWELL C LLYCKE'TTS B LUCY A LUGNUM C LUMBEE BID LUNT C LYNCHBURG C MACOVE B MADISON B MAGOTAIA D MANASSAS B MANOR B MANTACHIE c MANT'EO CID MARBIE c MARQ0 B MARLBORO B MARK B MARUMSCO c MASADA C MASSANETTA B MASSANUTTEN B MATAFEAKE B MATNELFLAT B MATTAN D COUNTY OF ROANOKE 7444X/1/16 4B-11 STORMWATER HYDROLOGY STORMWATER HYDROLOGY APPENDIX 4B Soil Name Hydgrp Soil Name Aydorij Suil .NaM H4`df.rn MATTAPEX C MATTAPONI C MAURERTOWN D MAYODAN B MCGARY C MCQUEEN C MEADOWS D MEADOWVILI.E B ME.CKLENBURG C MEGGETT D MELI+A D MELVIN D M L"(xm A MINNIEEV ILLS C ML= D ALLUVIUM MOLENA A MONACAN C MONGLE C MONONGAHELA C MONTALTO C MONTItE;SSOR* B MONTROSS C MOOMAW C MORRISONVILLE' B MOR VEN B MOUNT LUCAS C MT WEATHER'S B MUCKALEE D MUNDEN B MURRML B MYATT D MYATT VARIANT D MYERSVILLE B NAHUNTA C NANSEMOND C NASON B NAWN$Y D NEABSCO C NESTORIA CJD NEVARC C NEWARK C NEWBERN C NEWFLAT D NEWHAN A NEWMARC C NICHOLOSON C NTMMO D NIRA C NOLICHUCKY R NOLIN B NOMERVILLE B NORFOLK B OAKHILL B OAKLET C OATLANDS B OCCOQUAN B OCI-MOCKONEE B OKEETEE D OPEQLION C ORANGE D ORANGEBUItG B ORENDA S ORISKANY B OSIER Ao OTHELLO C..'D PACOLET B PACTOLUS A PAGEBROOK D PAMLICO D PAMUNKEY B PAMUNKEY A PANORAMA B VARLkNT PARKER B PARTLOW D PASQUOTANK Rn PEAKS C PEAWICK D PENN GD COUNTY OF ROANOKE 7444X/1/16 4B-12 STORMWATER HYDROLOGY STORMWATER HYDROLOGY APPENDIX 4B Soil tiumc Ilyd rp $oil Nam Hydgrp SW Na= Ficd= PHILO B PHMOMOMT' B PINEYWOODS D PINKSTON B PISGAH C POCATY D POCOMOK.E BID P61NDE=R B POLAWANA ArT) POOLER VARIANT D POPE B POPLWENTO C PORTERS B PORTSMOUTH Bo POUNCEY D PUNCO D PURCELLVnIF B PUIRDY D RABUM B RAINS BID RAMSEY D RAPIDAN B RAPPHANNOCK D RARITAN C RAYNE B READINGTON C REAVILLE. C RFVMW, A RIGLEY B TUON B RIVERVMW 13 ROANOKE D ROHRERSVILLE D ROSS B ROWLAND C RUMF'ORD B RUSHTOWN A RUSTON B SAFELL B SASSAFRAS B SASSAFRAS B VAtTNCX)K B SAVANNAH C SCATTBRSVTLLE• C SCHAFFE'NAKER A SBABROOK C SEDGEFIELD C SEKH, B SENECA B SEQUOIA C SI3ELOCTA B SHENVAL B SHERA DO B SIMVA C SHOT O YEIi B SINDION B SKETERVH,I:E C SLABTOWN B SLAGLE C SLICKENS B SNICKERSVILLE B SPEEDWELL B SPESSARD A SPIVEY B SPOSTSYLVANLA C SPRIGGS G SPRINGWOOD B STANTON D STARR C STATE B STEIN&BURG C STONEVILLE B STUART C STUWTOWN B SUCHES B SUDLEY B SUTEQUEHANNA D SUFFOLK B SUISDLEY B SUSQUEHANNA D SWAMP D COUNTY OF ROANOKE 7444x/1/16 STORMWATER HYDROLOGY 4B-13 STORMWATER HYDROLOGY APPENDIX 4B Cnil Name SWEETAPPLE ILYA= B 5611 Name SWIh•SLEY C Rail Name SYCOiINE Hydgrp D SYLCO C SYLVATUS D TALLADEGA C TALL.APOOSA C TARBORO A TATE B TATUM B TETOTUM C THUNDER B THURMONT B TIDAL MARSH D TBOERVLLLE B TIOGA B TOCCOA B TODDSTAV D TOMOTLEY av TOMS C TOR TA C TOTIER C TOYAWAY BiD TRAPPIST C TREGO B TREN19OLM D TUCKAHOE B TUMBLING B TURBEVILLE C TUSQUITEE B TYGART C UCHEE A U7DIFLUVE.NTS B UNISON B VANCE C VARINA C VAUCLUSE C VER.TREES B WADESBORO B WAHE� D WAKUL.LA A WALLEN B WARMINSTER C WATAUGzA $ WATEREE. B WATT D WAXPOOL D WEAVER C WEAVEP-TON* C WEBBTOWN C WEDOWEE B WEEKSVILLE BA) WEHADKEE D WEIICERT CSD WESTMORELAND B WESTON D WESTPHALLA B WEVERTON B WHEELING B WHITE STONE D WIIITEFORD B WICKHAM B WILKES C WOLFGAP B WOODINGTONT BID WORSHAM D WRIGHTSBORO C WRYICK B WURNO C V,TMCK B YADKIN CID YEMASSEE C YEOPIM B YORK C ZEPP B ZION C ZOAR C COUNTY OF ROANOKE 74/14x/1/16 STORMWATER HYDROLOGY 4B-14 STORMWATER HYDROLOGY APPENDIX 4C APPENDIX 4C INFORMATION FROM VDOT HYDRAULIC DESIGN ADVISORIES Rainfall Intensities (inches/hour) for the Roanoke Valley (Based on VDOT HDA 05-03) COUNTY OF ROANOKE 7444X/1/16 4C-1 STORMWATER HYDROLOGY STORMWATER HYDROLOGY APPENDIX 4C Note: For use with the Rational Method only. Use NOAA precipitation chart for SCS Method. RAINFALL INTENSITY (INMR) FOR THE ROANOKE VALLEY Table based on VDOT Hydraulic Design Advisory HAD 05-03 If = B / (% + D)E where: If = Rainfall intensity for a given recurrence interval, f, in inches per hour t� = Watershed time of concentration (assumed to equal the storm duration), in minutes B,D,E = As taken from HDA 05-03 table for [Roanoke] [Roanoke (city)] based on the designated storm frequency. COUNTY OF ROANOKE 7444k/1/16 4C-2 STORMWATER HYDROLOGY Storm Duration (min) 5 10 15 20 25 30 35 40 45 60 75 90 105 120 2 4.39 3.51 2.94 2.54 2.24 2.01 1.82 1.67 1.54 1.26 1.07 0.94 0.83 0.75 5 5.33 4.29 3.62 3.14 2.79 2.52 2.30 2.12 1.96 1.63 1.40 1.23 1.10 1.00 10 6.04 4.91 4.18 3.66 3.26 2.96 2.71 2.51 2.34 1.96 1.69 1.50 1.35 1.23 25 6.78 5.49 4.68 4.11 3.69 3.36 3.10 2.88 2.70 2.28 2.00 1.79 1.63 1.50 0 50 7.37 5.96 5.09 4.49 4.04 3.70 3.42 3.19 3.00 2.56 2.26 2.04 1.87 1.73 CA 1001 8.08 6.49 5.56 4.92 4.46 4.10 3.81 3.57 3.37 2.92 2.61 2.37 2.19 2.04 Table based on VDOT Hydraulic Design Advisory HAD 05-03 If = B / (% + D)E where: If = Rainfall intensity for a given recurrence interval, f, in inches per hour t� = Watershed time of concentration (assumed to equal the storm duration), in minutes B,D,E = As taken from HDA 05-03 table for [Roanoke] [Roanoke (city)] based on the designated storm frequency. COUNTY OF ROANOKE 7444k/1/16 4C-2 STORMWATER HYDROLOGY OPEN CHANNELS Chapter 5 — Open Channels CHAPTER 5 Open channels are man-made ditches and channels and natural channels, that are used to convey stormwater flow. This section defines criteria and restrictions to be used in designing open channels. Where open channels are a part of a BMP, they shall comply with the state requirements for the purposes of water quality improvement; however, they shall also comply with this Design Manual's requirements for water conveyance. 5.1 References The primary design references are: • VDOT Drainage Manual • VDOT Specifications • VA E&SC Handbook • Hydraulic Engineering Circular Number 15 (HEC -15), Design of Roadside Channels with Flexible Linings, Current Edition, as amended • VA SWM Handbook 5.2 Design Methodology and Criteria 5.2.1 Major and Minor Manmade Open Channels A major channel is designed to convey less frequent storm events which would have significant adverse consequences if it failed. Major channels protect buildings and other important features from flooding and catastrophic failures. A minor channel is designed to convey more frequent storm events and they include most onsite open channels and roadside ditches. These structures have less adverse consequences due to overtopping. 5.2.2 Design Flow Design flow for manmade open channels within a development is contained in Chapter 4.2.2. Channels shall be designed to convey the 10 -year flow. Additionally, all storm drainage designs for open channels, culverts, and storm drains shall be checked for the 100 -year flow condition where there is the possibility of flooding residences, commercial or industrial buildings, overtopping primary roads, experiencing significant economic loss, or catastrophic failure. Where justified by the consequences of failure, the minimum design frequency COUNTY OF ROANOKE 7444X/1/16 5-1 OPEN CHANNELS OPEN CHANNELS CHAPTER 5 shall be increased. Design flows for downstream channels and all natural channels shall comply with the VA SWM Regulations. 5.2.3 Hydrology See Chapter 4 for methodology used to determine peak flows for a given design frequency. 5.2.4 Channel Hydraulics Open channel design will be based on Manning's Equation for open channel flow, unless good engineering practice dictates using HEC -RAS or other method. See the VA SWM Handbook and VDOT Drainage Manual, as appropriate. Q= A x 1.49/n x Rz/' x Slit Where: Q = Flow in the open channel (cfs) A = Cross-section area of the channel (ft) R = A/wetted perimeter (ft) S = Channel slope (ft/ft) n = Channel roughness coefficient Nomographs have been included in Appendix 5A for use in solving Manning's equation setting channel characteristics. 5.2.5 Channel Velocity The lining of minor channels with drainage areas of five acres and less shall be designed to withstand the erosive effects of a 2 -year storm. The lining of minor channels with drainage areas over five acres and major channels shall be designed to withstand the erosive effects of a 10 -year storm. The final design shall be consistent with velocity limitations for the selected channel lining, as presented in Table 5-1. Major channels associated with dam embankment spillways or other structures where catastrophic failure could result from a lining failure may be required to be designed to withstand a more severe storm event. Where open channels receive flow from storm drains, culverts, or other open channels, or in other areas where channel velocity may cause scouring or erosion, outlet protection or energy dissipation may be necessary to reduce the potential for severe erosion. For the design of energy dissipation devices, see Chapter 10. COUNTY OF ROANOKE 7444X/1/16 5-2 OPEN CHANNELS OPEN CHANNELS TABLE 5-1 Maximum Velocity Based on Channel Lining CHAPTER 5 Channel Lining Maximum Velocity (Design Storm) Erosion Resistant Easily Erodible Soils Soils Vegetative Lined Channels Tall Fescue Grass Mixtures 6 fps 4 fps Kentucky Bluegrass 6 fps 4 fps Annual and Perennial Rye 4 fps 3 fps Sod 4 fps 3 fps Geos nthetic LinqA VDOT EC -2 4 fps VDOT EC -3, Type I f s VDOT EC -3, 10 fps Other Per Mfr Recommendations Riprap (see VDOT Drainage Manual Appendix 7-D for n valuesl Dependent on stone size and thickness, see HEC -15 for design of riprap channels Concrete None 1 Erosion resistant soils include those with a high clay content and high plasticity, silty clay, sandy clay, and clay. 2 Easily erodible soils include those with a high content of fine sand or silty, lower plasticity or non -plastic, sand, silt, sandy loam, and silty loam with an erodibility factor (K) greater than 0.35. 3Soils shall be presumed to be easily erodible; unless a geotechnical investigation is performed that samples and tests the soils. 4All channels constructed in fills shall be considered to be in easily erodible soils. 5.2.6 Channel Slope Generally the channel slope shall be established by the site topography. Open channels must be graded to drain with no standing water following a rain event. The minimum allowable grade shall generally be 2 percent for vegetated -lined and riprap-lined open channels and 1 percent for a concrete open channel. The maximum allowable grade for a stormwater channel shall be dependent on the channel lining materials and its ability to withstand erosion during the design storm. COUNTY OF ROANOKE 7444X/1/16 5-3 OPEN CHANNELS OPEN CHANNELS 5.2.7 Cross Sectional Area CHAPTER 5 Open channel cross-section area shall be designed based on site restrictions and channel capacity requirements. The following information as a minimum shall be - , - Formatted: Highlight provided in either a table and/or detail on the design plans that includes the - Formatted: Highlight channel number if multiple swales are proposed, bottom width, top width, slope, Formatted: Highlight side slopes, total depth including freeboard, and liner. Each swale should be Formatted: Highlight included in the chart and not just a worst case scenario. Additionally, Qo, QI 0 water depth, freeboard provided, and Vshall be clearly ..- - Formatted: Subscript indicated in the calculations. - Formatted: Subscript Formatted: Subscript Acceptable cross-sectional area options include: • Vee • Parabolic • Trapezoidal Rectangular - - Formatted: List Paragraph, No bullets or numbering, Tab Yard stops: Not at 1.5' ---------------------------------------------- Formatted: Highlight A. `Vee - - - - - --------------------------------------- Formatted: Font: Bold For design aids, see the VDOT Drainage Manual and the VA E&SC Handbook. Additionally computer software such as North American Green, Flowmaster, etc. can be used for design aids. The maximum side slope of a vee -shape open channel is 3 horizontal to ] vertical for vegetated channels (including reinforced vegetated) and is 2 horizontal to 1 vertical for all other linings engineered to be stable at this slope. B. Yarabolic ------------------------------------------ -- Formatted: Font: Bold For design aids, see the VDOT Drainage Manual and the VA E&SC Handbook. Additionally computer software such as North American Green, Flowmaster, etc can be used for design aids. COUNTY OF ROANOKE 7444X/1/16 5-4 OPEN CHANNELS OPEN CHANNELS CHAPTER 5 C._ Trapezoidal Formatted: Font: Bold For design aids, see the VDOT Drainage Manual and the VA E&SC Handbook. Additionally computer software such as North American Green, Flowmaster, etc. can be used for design aids. The maximum side slope of a trapezoidal -shape open channel is 3 horizontal to 1 vertical for vegetated channels (Including reinforced vegetated) and is 2 horizontal to 1 vertical for all other linings engineered to be stable at this slope. p.___ Rectangular ......... ------------------------------ Formatted: Font: Bold Rectangular channels shall only be allowed where site restrictions prevent the installation of a vee, parabolic, or trapezoidal channel. The requirements for rectangular channels apply to any open channel with side slopes greater than 2 horizontal to 1 vertical. Rectangular channels must either be concrete or gabions. An approved safety barrier must be placed on both sides for the length of the rectangular channel, where the channel is more than 3 -feet deep. Care must be taken to ensure that energy dissipation is placed at the outfall of the rectangular channel to prevent erosion at the discharge point. E. Yard-------------------------------------------`' ------------------------------------------------------------- Yard swales that do not convey stormwater over multiple lots can utilized _ basic yard swale detail without providing calculations if the following - f - - conditions are met: less than 0.25 acres drainage area., 2A�/o minimum longitudinal . lope, 6% maximum longitudinals lope, side slope of 4:1. H:V T\ (maximum 3:ll,-bottom-width-of 0 feet, total depth of 1.1', applicable top width based on side slopes, and type of liner labeled (i.e. grass Designer shall show a detail on the plan that meets the basic yard swale criteria. All other yard swale twill required calculations and an. pplicable detail. Yard swales mustrg ass. COUNTY OF ROANOKE 7444X/1/16 5-5 OPEN CHANNELS Formatted: Highlight Formatted: Indent: Left: 1", Hanging: 0.5" Formatted: Font: Bold, Highlight Formatted: Highlight Formatted: Highlight Formatted, Highlight Formatted: Highlight Formatted: Highlight Formatted: Highlight Formatted: Highlight Formatted: Highlight Formatted: Highlight Formatted: Highlight Formatted: Highlight Formatted: Highlight Formatted: Highlight � Formatted: Highlight Formatted: Highlight OPEN CHANNELS 5.2.8 Channel Lining CHAPTER 5 An open channel lining shall be designed based on the cross-section, slope, and channel velocity requirements. The design may be based on a consideration of either permissive velocity or tractive force as described in the VDOT Drainage Manual. The preferred method for analyzing channel linings is to compare the maximum permissible velocity for the channel lining, listed in Table 5.1 in this chapter of the Design Manual, to the design velocity computed using Manning's equation to verify that the selected lining is adequate. As an alternative, the selected lining may be analyzed using the Tractive Force Method published in the VDOT Drainage Manual. This method analyzes sediment critical shear loading on the open channel bottom and side slope. The permissible tractive force for various soils is located in the Appendix of the VDOT Drainage Manual. Open channels may have different lining materials in different channel reaches based on velocity and potential erosion conditions. Care must be exercised to avoid erosion at open channel transition points. The open channel lining will have an impact on the design capacity in the form of the roughness coefficient. A table of generally accepted roughness coefficient (n) for various channels and linings is included in Appendix 5A. Allowable open channel linings include the following: A. jiatural ... Formatted: Font: Bold To the maximum extent possible, natural channels shall be preserved. Design discharges from permitted land disturbing activities shall comply with the VA SWM Regulations. J1 _ _ Vegetative -Lined - I Formatted: Font: Bold Vegetated or grass -lined channels include man made channels lined with established vegetation. These channels usually include a geosynthetic mat for channel stabilization. The type of grass allowable for vegetative -lined open channels is dependant on the slope of the channel, and the peak calculated velocity. Table 5-1 details the maximum permissible velocities for various channel linings. COUNTY OF ROANOKE 7444X/1/16 5-6 OPEN CHANNELS OPEN CHANNELS CHAPTER 5 A permanent channel stabilization geosynthetic mat should be considered for all vegetated channels. There are a wide variety of geosynthetic stabilization mat options from various manufacturers. The geosynthetic mat selected should be adequate for the slope and design flow velocities calculated for the channel. Where appropriate, VDOT Road and Bridge Standard EC -2 or EC -3 may be used. Where a permanent geosynthetic mat is used to provide channel stabilization, information on the proposed mat, in the form of manufacturer's catalog information, shall be submitted as a part of the stormwater management plan. The catalog information shall include the manufacturer's recommendations for maximum allowable velocity. Design drawings must state that the geosynthetic stabilization mat shall be installed in strict accordance with the manufacturer's recommendations. Where a permanent channel stabilization geosynthetic is not used, a temporary geosynthetic lining designed to provide a measure of bank stability until such time a reasonably stable and mature stand of vegetation is established shall be provided. C.- - - Riprap-Lined-------------------------------- _ Formatted: Font: Bold The use of vegetated and geosynthetic-lined open channels for gentle - sloped open channels and concrete for steep -sloped open channels is recommended. Riprap-lined channels will not be acceptable where vegetated or geosynthetic-lined open channels are feasible. However, where design flow velocities exceed the erosive capability of a natural or vegetative -lined channel, rip rap may be used as a channel liner in areas where erosion is a concern. For an extended length of high velocity channel, consideration should be given to using a concrete channel rather than rip rap. Riprap lining shall be properly embedded in accordance with VDOT standards to maintain intended ditch cross section. Where riprap is required due to velocity conditions, it shall meet VDOT Standards and VDOT Specifications. VDOT recommended 50 percent stone size (D5o) and weight (W5o) and recommended thickness (T) for various riprap classifications is included in Appendix 5A. P. Concrete -Lined - - I Formatted: Font: Bold Reinforced concrete shall be considered where design velocities dictate or where there is a need to provide the maximum level of erosion protection. COUNTY OF ROANOKE 7444X/1/16 5-7 OPEN CHANNELS OPEN CHANNELS 5.2.9 Freeboard Requirements CHAPTER 5 Manmade channels within a development shall have a minimum of 6" of freeboard above the calculated water level during the design peak flow, unless flow is supercritical. Where flow is supercritical, a minimum of 12" of freeboard is required. Yard swales require 6" of freeboard._ Flow -is supercritical when: _ _ _ - - I Formatted: Highlight V/(32.2xIT)05> 1 Where: V — velocity (fps) H — depth of flow (feet) At bends and curves, the freeboard shall be measured from the calculated water level, including the increased depth due to the superelevation of the water surface. 5.2.10 Calculation of Depth of Flow at Bends and Curves Increases in the depth of flow occur at bends and curves due to the superelevation of the water surface. Superelevation of the water surface at bends and curves is calculated by: AZ — Vz / (32.2 x r�) x (ro — ri) where AZ — difference in water surface elevation between the concave and convex banks (ft) V — average velocity (ft/s) r� — radius of the center of the stream at the bend (fl) ro — radius of the outside bank of the stream at the bend (ft) ri — radius of the inside bank of the stream at the bend (fl) The increase in the normal stream flow depth at the outer bank of an open channel bend is one half of AZ. 5.2.11 Channel Location and Width Restrictions on Residential Lots The tops of open channel banks shall be at least 20 -feet from a residence. Where manmade open channels collect stormwater from more than one lot and they are located on a residential zoned lot their use shall be restricted as follows. Where all requirements cannot be met, a closed pipe storm drain system is required. COUNTY OF ROANOKE 7444X/1/16 5-8 OPEN CHANNELS OPEN CHANNELS CHAPTER 5 • Residential lot size 1 acre or greater o No additional restrictions. • Residential lot size 0.5 acre or greater, but less than 1 acre o Open channel top width shall be a maximum of 15 feet o Maximum drainage area passing through the open channel shall be 5 acres. • Residential lot size less than 0.5 acre o Open channel top width shall be a maximum of 15 feet o Maximum drainage area passing through the open channel shall be 3 acres. The above restrictions do not apply if any one of the following conditions is present: • The open channel is a natural channel that has adequate capacity. The retention of natural channels is encouraged. • The open channel is a perennial or intermittent stream that has adequate capacity and will remain undisturbed. • It may be demonstrated that open channels are required as a part of an integrated design to obtain the necessary water quality treatment. 5.3 Environmental Considerations and Fishery Protection Construction or modifications to open channels shall comply with all applicable laws and regulations. The applicant is responsible for procuring all necessary permits, such as US Army Corps of Engineers and VA DEQ Wetland Permits, VA DEQ VPDES Permits, etc., prior to obtaining a Land Disturbance Permit. A copy of these permits shall be submitted to Roanoke County prior to scheduling the precon meeting or the Engineer shall submit a 3rd party report to the County that supports that the permits are not required. 5.4 Maintenance Requirements The permittee is responsible for maintenance of open channels until construction is complete, including final clean up and site stabilization, to the satisfaction of the County of Roanoke. After the completion of construction, the property owner is responsible for maintenance of open channels. Maintenance includes periodically pruning or mowing vegetation and removing debris. COUNTY OF ROANOKE 7444X/1/16 5-9 OPEN CHANNELS OPEN CHANNELS 5.5 Floodplain Studies CHAPTER 5 A floodplain study shall be performed for all drainage areas greater than 100 acres that do not have detailed FEMA Flood Insurance Study flood profiles or elevations. See Chapter 12 for additional information on floodplain requirements. COUNTY OF ROANOKE 7444X/1/16 5-10 OPEN CHANNELS OPEN CHANNELS APPENDIX 5A AIDS FOR OPEN CHANNEL DESIGN FROM CHAPTER 7, VDOT DRAINAGE MANUAL Appendix 7B-1, LD -268, Roadside and Median Ditch Design Form Appendix 7B-3, Channel Stability Work Sheet APPENDIX 5A Appendix 7B-4, Riprap Design Work Sheet for Standard VDOT Riprap Sizes Only Appendix 7B-5, Riprap Design Work Sheet for other than VDOT Standard Riprap Sizes Appendix 7C-1, Nomograph for Solution of Manning's Equation Appendix 7C-2, Trapezoidal Channel Capacity Chart Appendix 7C-3, Nomograph for Solution of Normal Depth Appendix 7D-1, Values of Roughness Coefficient n, 2 sheets Appendix 7D-3, Standard VDOT Riprap Classifications, Weights, and Blanket Thickness Appendix 7D-5, Selection of Stability Factors Appendix 713-6, Permissible Velocities for Erodible Linings Appendix 7E-1, Angle of Repose of Riprap in Terms of Mean Size and Shape of Stone Appendix 7E-2, Permissible Shear Stress for Non -Cohesive Soils Appendix 7E-3, Permissible Shear Stress for Cohesive Soils Appendix 7E-4, Bank Angle Correction Factor (Ki) Nomograph Appendix 7E-5, Correction Factor for Riprap Size Appendix 7E-6, Riprap Size Relationship Appendix 7E-7, Channel Side Shear Stress to Bottom Shear Stress Ratio COUNTY OF ROANOKE 7/1444/1/16 5A-1 OPEN CHANNELS OPEN CHANNELS Appendix 7E-8, Tractive Force Ratio (K2) Appendix 7E-9, Determination of Mean Spherical Diameter COUNTY OF ROANOKE 7444X/1/16 5A-2 APPENDIX 5A OPEN CHANNELS OPEN CHANNELS APPENDIX 5A COUNTY OFROANOKE ^//1�t dx/1/16 5A-3 OPEN CHANNELS OPEN CHANNELS CHANNEL STABILITY WORKSHEET CHANNEL DATA Q = WS) P = (ft-) So _ (ft!ft) R = (ft.) d. (R) '- (fpr,) A=--- ,(ftp) Sine Slope = ;1 STABILITY OF NATIVE MATERIAL 70= 62,4+ R • Sa K, 11 - (sir? 0 / sir? - 62.4. Tp Bed - (Appendix 7E-2 or 3) For D5c= _ ° (Appendix 7E-1) For D7s = _ ° (Appendix 7E-9) Side Slope = _ = A 0=— K,=[1-(sir?9/sir? ]l 0.5 Ki = [1- (sir? / sir's ,)] 15 = Ts Side Slope (SS) = Tp Bed K = TP Bed ( ) (<) (=) (>) T. ( ) Native Material on Bed is (stable) (unstable) TS SS ( ) (<) (=) N to ( ) Native Materpal on Side Slope is (stable) (unstable) APPENDIX 5A Native Material D50 D75 _ n= COUNTY OF ROANOKE 74/14x/1/16 OPEN CHANNELS 5A-4 OPEN CHANNELS RIPRAP DESIGN WORKSHEET (VDOT STANDARD SIZES) CHANNEL DATA Q = (cfs) Sp (fuft) L1,= (ft.) A= (ft -2) DETERMINE RIPRAP SIZE � = 42° Side Slope = Pry = _(ft') R e (t.) V. ` (fps) Side Slope = I 0= 0 K, ` [1 - (sin2 0 I Sine ] 0,5 K, = [1 - (sing �° I sine 4n] 0 5 _ 1 For Specific Gravity = 2.65 and Stability Factor 4 1.2 D,=0.001 •Va3I(dew®05*K,8 D60 = 0.001 • 3/ ( �.$ , ,.) APPENDIX 5A D60 Computed = Note: All VDOT standard dprap (Class Al through Type II) is assumed to have a 0 of ,approximately 4V and a Specific Gravity of 2,55. Therefore, the Computed D50 should be adjusted by the Stability Correction Factor (CSF) (if any) to derive a Final D5, The VDOT slarxt�ard class of ripiap with the next higher D5q sTwuld bu speraried. Correction Factor For Stability Factor (SF) other than 1.2 (Default= 1.0) Csr =( F 11.2),.3 =( 11 2), 5 Final D5a- C57 • Computed D,a = • — RIPRAP RECOMMENDATiON: VDOT (Class) (Type) Thickness (T ) = " (2 • DEO MSD minimum) COUNTY OF ROANOKE 7414x/1/16 OPEN CHANNELS 5A-5 OPEN CHANNELS RIPRAP DESIGN WORKSHEET (NON—VDOT STANDARD SIZES) CHANNEL DATA Q = (rfs) P = (ft.) n = So = (ft/ t) R = (ft.) dfi= 00 V� (fp3) A= (ft) Side Slop: _ A ASSUMED RIPRAP SIZE - Dw = VERIFY ASSUMED RIPRAP SIZE APPENDIX 5A _ ° (Appendix 7E-11) Serle Slope - :1 O= ° K,=[1-(sin26/sine+))9'5 K, = [1 - (sing -0/sin e iI 0.5 = For Specific Gravity = 2.65 and Stability Factor = 1.2 tD,=0.001V/3I(d�'D'- '.) D5„ = D.DD1 • s 1 ( 0.5 , 1 sj = Deo Computed (_) (E) (=) (>) Dso Assumed ( ) Assumed Dso is (correct) (incorrect) Note= The above process of assuming a %, size, determining the natural angle of repose (0) and computing a D5o size should be repeated until the Assumed Dw size equals the Computed DSD size. Once the %,, size determination has been made, it should be adjusted for the Specific Gravity Correction Factor C, (if any) and the Stability Correction Factor (Cs,) (if any) to derive a Final D, Correction Factor For Riprap Specific Gravity (S3) other than 2.65 (Default = 1.4) C,=2.12/(% -1),.s = 2.121( - 1)1.s = Correction Factor For Stability Factor (SF) other than 1.2 (Defauk = 1.0) CSF = (SF 1 1.2)'.s = ( / 1.2)' 6 = Final Correction Factor = C = C.9 ■ C' = _ Final D..= C +Computed D RIPRAP RECOMMENDATION' Thickness (T) = " (2 • D60 MSD minimum) COUNTY OF ROANOKE 7444X/1/16 5A-6 OPEN CHANNELS OPEN CHANNELS APPENDIX 5A NOMOGRAPH FOR SOLUTION OF MANNINGS EQUATION G9+R � noCid h � Al .e } LA 6 COUNTY OFROANOKE 7/1444/1/16 5A-7 an 4 OPEN CHANNELS OPEN CHANNELS APPENDIX 5A TRAPEZOIDAL CHANNEL CAPACITY CHART 11 II u n rl N C7 N ^ 4 d O Q 4 ]n 8 COUNTY OFROANOKE 7/1444/1/16 5A-8 m ci OPEN CHANNELS OPEN CHANNELS APPENDIX 5A NOMOGRAPH FOR SOLUTION OF NORMAL DEPTH d NSTE= Fa a wlzmlal lY f w Z.0 *r h y Q to oMofn vwkm for 2 = 1 10 a r+ m ,r m 4.P d 1 S SUW I POM `57.1 On 0.08 (FT 3,(S) 0,06 2 ❑ C7A5 SL574 -10 Ld 0.ca ®-4 J FZ t7 S.d d_04 V Z 3,0 t— 0.002 cz Ota •n.rt 9A@ O.Ofi SL9� 4.513 AFF) j EXAMPLE: "0 VVEh: FIND. SUW I POM S-0.01 d Gaa0.3 9=1Q FT3/s 00.0.14 a. U.03 d=4.1444)=O56 ET 8-4 FT Z-4 1 4.2 O.® 1.0 COUNTY OF ROANOKE 7414x/1/16 OPEN CHANNELS 5A-9 OPEN CHANNELS APPENDIX 5A VALUES OF ROUGHNESS COEFFICIENT `n' CHANNELS Type of Channel and Description Minimum Normal Maximum LINED CHANNELS (Selected linings) a. Concrete 1. Trowel finish 0.011 0.013 0.015 2. Float finish 0.013 0.015 0.016 3. Gunite, good section 0.016 0.019 0.023 b. Asphalt 1. Smooth 0.013 0.013 --- 2. Rough 0.016 0.016 --- EXCAVATED OR DREDGED a. Earth, straight and uniform 1. Clean, recently completed 0.016 0.018 0.020 2. Clean, after weathering 0.018 0.022 0.025 3. Gravel, uniform section, clean 0.022 0.025 0.030 4. With short grass, few weeds 0.022 0.027 0.033 b. Earth, winding and sluggish 1. No vegetation 0.023 0.025 0.030 2. Grass, some weeds 0.025 0.030 0.035 3. Dense weeds or aquatic plants in deep channels 0.030 0.035 0.040 4. Earth bottom and rubble sides 0.025 0.030 0.035 5. Stony bottom and weedy sides 0.025 0.035 0.045 6. Cobble bottom and clean sides 0.030 0.040 0.050 c. Dragline excavated or dredged 1. No vegetation 0.025 0.028 0.033 2. Light brush on banks 0.035 0.050 0.060 d. Rock cuts 1. Smooth and uniform 0.025 0.035 0.040 2. Jagged and irregular 0.035 0.040 0.050 e. Channels not maintained, weeds and brush uncut 1. Dense weeds, high as flow depth 0.050 0.080 0.120 2. Clean bottom, brush on sides 0.040 0.050 0.080 3. Same, highest stage of flow 0.045 0.070 0.110 4. Dense brush, high stage 1 0.080 1 0.100 1 0.140 COUNTY OF ROANOKE 74/14x/1/16 5A-10 OPEN CHANNELS OPEN CHANNELS APPENDIX 5A VALUES OF ROUGHNESS COEFFICIENT `n' NATURAL STREAMS Type of Channel and Description Minimum Normal Maximum NATURAL STREAMS 1. Minor streams (top width at flood stage <100 ft) a. Streams on Plain 1. Clean, straight, full stage, no rifts or deep pools 0.025 0.030 0.033 2. Same as above, more stones and weeds 0.030 0.035 0.040 3. Clean, winding, some pools/shoals 0.033 0.040 0.045 4. Same as above, but some weeds and stones 0.035 0.045 0.050 5. Same as above, lower stages, more ineffective 0.040 0.048 0.055 slopes and sections 6. Same as 4, but more stones 0.045 0.050 0.060 7. Sluggish reaches, weedy, deep pools 0.050 0.070 0.080 8. Very reedy reaches, deep pools or floodways 0.075 0.100 0.150 with heavy stand of timber and underbrush b. Mountain Streams (no vegetation in channel, banks usually steep, trees and brush along banks submerged at high stages) 1. Bottom: gravels, cobbles, few boulders 0.030 0.040 0.050 2. Bottom: cobbles with large boulders 0.040 0.050 0.070 2. Floodplain a. Pasture, no brush 1. Short grass 0.025 0.030 0.035 2. High grass 0.030 0.035 0.050 b. Cultivated area 1. No crop 0.020 0.030 0.040 2. Mature row crops 0.025 0.035 0.045 3. Mature field crops 0.030 0.040 0.050 c. Brush 1. Scattered brush, heavy weeds 0.035 0.050 0.070 2. Light brush and trees, in winter 0.035 0.050 0.060 3. Light brush and trees, in summer 0.040 0.060 0.080 4. Medium to dense brush, in winter 0.045 0.070 0.110 5. Medium to dense brush, in summer 0.070 0.100 0.160 d. Trees 1. Dense willows, summer, straight 0.110 0.150 0.200 2. Cleared land with tree stumps, no sprouts 0.030 0.040 0.050 3. Same as above, but with heavy sprout growth 0.050 0.060 0.080 4. Heavy stand of timber, a few down trees, little 0.080 0.100 0.120 undergrowth, flood stage below branches 5. Same as above, but with flood stage reaching 0.100 0.120 0.160 branches 3. Major Streams (top width at flood stage > 100 ft) a. Regular section with no boulders or brush 0.025 --- 0.060 b. Irregular and rough section 0.035 --- 0.100 (The n value is less than that for minor streams of the same description, because banks offer less effective resistance.) COUNTY OF ROANOKE 74/14x/1/16 5A-11 OPEN CHANNELS OPEN CHANNELS APPENDIX 5A STANDARD VDOT RIPRAP CLASSIFICATIONS, WEIGHTS, AND BLANKET THICKNESS Classification D50 (ft) W50 (lbs) T (in) Class Al 0.8 50 20 Class I 1.1 100 26 Class II 1.6 300 38 Class III 2.2 1000 53 Type I 2.8 2000 60 Type II 4.5 8000 97 SELECTION OF STABILITY FACTORS Condition Stability Factor Range Uniform flow; straight or mildly curving reach (curve radius/channel 1.0- 1.2 width >30); impact from wave action and floating debris is minimal; little or no uncertainty in design parameters. Gradually varying flow; moderate bend curvature (30 > curve 1.3 - 1.6 radius/channel width > 10); impact from waves or floating debris is moderate. Approaching rapidly varying flow; sharp bend curvature (30 > curve 1.6-2.0 radius/channel > 10); significant impact from floating debris and/or ice, significant wind and/or bore generated waves (1-2 feet); high flow turbulence; mixing flow at bridge abutments; significant amount of uncertainty in design parameters. Channel bends when ratio of curve radius to channel width (R/W) > 30. 1.2 Channel bends when 30 > R/W > 10. 1.3- 1.6 Channel bends when R/W < 10. 1.7 COUNTY OF ROANOKE 7444X/1/16 5A-12 OPEN CHANNELS OPEN CHANNELS APPENDIX 5A PERMISSIBLE VELOCITIES FOR ERODIBLE LININGS Soil type or lining (earth; no vegetation Maximum permissible velocities ft/sec for Water Water carrying Clear carrying sand and water fine silts gravel Fine sand (non colloidal) 1.5 2.5 1.5 Sandy loam (non colloidal) 1.7 2.5 2.0 Silt loam (non colloidal) 2.0 3.0 2.0 Ordinary firm loam 2.5 3.5 2.2 Volcanic ash 2.5 3.5 2.7 Fine gravel 2.5 5.0 3.7 Stiff clay (very colloidal) 3.7 5.0 3.0 Graded, loam to cobbles (non colloidal) 3.7 5.0 5.0 Graded, silt to cobbles (colloidal) 4.0 5.5 5.0 Alluvial silts (non colloidal) 2.0 3.5 2.0 Alluvial silts (colloidal) 3.7 5.0 3.0 Coarse gravel (non colloidal) 4.0 6.0 6.5 Cobbles and shingles 5.0 5.5 6.5 Shales and hard pans 6.0 6.0 5.0 COUNTY OF ROANOKE 7444X/1/16 5A-13 OPEN CHANNELS OPEN CHANNELS APPENDIX 5A ANGLE OF REPOSE OF RIPRAP IN TERMS OF MEAN SIZE AND SHAPE OF STONE MEAN STONE SIZE, ❑S0, FT. 6 8 s i9 2Q 3a 44 Sa 80 lug 29G 300 41m Bao COUNTY OF ROANOKE ^Nisi dx/1/16 MEjkN STONE SIZE, 050.mu,r 5A-14 OPEN CHANNELS OPEN CHANNELS APPENDIX 5A PERMISSIBLE SHEAR STRESS FOR NON -COHESIVE SOILS COUNTY OF ROANOKE 74/14x/1/16 )o PA€?TICLF- 01AMETER, 1) (mrn) 5A-15 OPEN CHANNELS OPEN CHANNELS APPENDIX 5A PERMISSIBLE SHEAR STRESS FOR COHESIVE SOILS t_e 4.5 '% 0.1 lb/112 0.06 0.DI COUNTY OF ROANOKE 7444X/1/16 Chart 2 a_a o6.4 #4.0 P1,ASTl-v ITY INDEX — PA. 5A-16 OPEN CHANNELS HIM ME ME SPA, MEN a_a o6.4 #4.0 P1,ASTl-v ITY INDEX — PA. 5A-16 OPEN CHANNELS OPEN CHANNELS APPENDIX 5A BANK ANGLE CORRECTION FACTOR (K1) NOMOGRAPH 1 74444X/1/16 o Ki - sin sin = Bank angle w-th horizontal m . Material angle of repose (See chart 4) () M 0 M 35 34 1.5,1 K1 .10 34 za .30 2:1 so 25 1 .7Q35 -- . 2i1 ^" 40, 3.5:1_L �a Example Given: Find: Solution; C, 'O186 K o .-c YCF Vary Angular � K1= 0.885 DSO= 1,5 ft. 5A-17 OPEN CHANNELS OPEN CHANNELS APPENDIX 5A CORRECTION FACTOR FOR RIPRAP SIZE C = i.6i SFI-11(Ss -1),.3 C _ D 5q CORRI70ION FACTOR SF = STABILITY FACTOR Ss= SPE=CIFIC GRAVITY OF ROCK Ss c SF 54 2.4 2,0 4.0} 1.9 2-1 1.8 3,0- 22 1,7 25 1,6 2.5- .32,(Y 2.0-- - 1.5 1.5 2-# y S 1.4 2,5- 1.3 2.B 2.0 2.7- .72'5 2.5- 2.9- 2.83.4 3,0 1.0 Q.� Example: Given_ Soluflo : Ss 2.65 C=1-0 SF = 1.2 COUNTY OF ROANOKE 7444k/1/16 5A-18 OPEN CHANNELS OPEN CHANNELS APPENDIX 5A RIPRAP SIZE RELATIONSHIP D . 7 offLrm R.wikp Sato ( a Vs - Avera4o valapty 4n main r}n mc4 tA1rAc} d mg- Average depm In maLi camel (M 4 5d K, _ Eank angle mnjK4on wm 02 020 r dam y' Of 40as f° OA r 20 a0 r �JO r 2S- 15 r s 24 r {� 1.0 75 10 .4 10 6 4 W 3 4 EXRMp le {3hren: Fndi K, � d-73 1 74444X/1/16 5A-19 WLIUD& 0 M .4.43 OPEN CHANNELS ']9Wro0V.10 10116 COUNTY OFROANOKE 7/1444/1/16 5A-20 APPENDIX 5A SIDE SLOPE w 4 yy ki 1.5 M OPEN CHANNELS OPEN CHANNELS 45 40 E d a � e w W 20 0 ww W 15 r9 iJ Y TRACTIVE FORCE RATIO (K2) APPENDIX 5A Chart 14 WousisLe-i -.. I I m NEESE- J 0-2 OA D.6 0.8 1.Q COUNTY OFROANOKE 7444X/1/16 5A-21 KZ OPEN CHANNELS OPEN CHANNELS APPENDIX 5A DETERMINATION OF MEAN SPHERICAL DIAMETER 10, 011D b ilk c: NIS 2.92 2.56 2.24 $_7B L.51 1,32 1 COUNTY OFROANOKE 7414x/1/16 OPEN CHANNELS 5A-22 CULVERTS Chapter 6 - Culverts CHAPTER 6 A culvert is a single run of storm drain pipe that conveys water or stormwater under a road, railway, embankment, sidewalk, or other obstruction. A culvert typically connects two open channels, but they may connect an open channel to a storm drain. Proper culvert design must consider many factors including: • Design Flow • Inlet conditions (flow approach conditions, allowable headwater, culvert inlet configuration) • Culvert conditions (material roughness, pipe slope, and length) • Tailwater depth • Buoyancy potential • Environmental considerations and effects on aquatic life • Design loads and service life of the pipe material Refer to the VDOT Drainage Manual, for a more through discussion of these items. For the design of stormwater inlets and storm drains, see Chapter 7. 6.1 References Except where more stringent requirements are presented in this Design Manual, culverts shall comply with VDOT requirements. The primary design reference is the VDOT Drainage Manual. Other appropriate references include: • VDOT Standards • VDOT Specifications • VA E&SC Handbook • VDOT Instructional and Informational Memorandum IIM-1D-121.15, Allowable Pipe Criteria for Culverts and Storm Sewers • FHWA Hydraulic Design of Highway Culverts HDS No. 5, Pub. No. FHWA- NHI-01-020, Current Edition, as amended • FHWA Debris Control Structures Evaluation and Countermeasures HEC No. 9, Pub. No. FHWA-IF-04-016, Current Edition, as amended COUNTY OF ROANOKE ;444x/1/16 6-1 CULVERTS CULVERTS CHAPTER 6.2 Design Methodology and Criteria 6.2.1 Computation Methods Manual computations use design equations and nomographs. Results are documented on VDOT's Design Form LD -269. Form LD -269 is included in Appendix 6A. There are a number of computer programs available to design culverts. Any of these computer programs will be acceptable if their methodologies are based on the same equations and nomographs accepted by VDOT, and if they provide the same documentation of inputs, assumptions, and output as are contained on VDOT's Design Form LD -269. 6.2.2 Hydrology �1. Design Flow Methodology Formatted: Font: Bold See Chapter 4 for methodology used to determine design flows. Generally culverts shall be designed based on the peak flow (steady state), ignoring the effects of temporary upstream storage. �. Obstruction Allowance Formatted: Font: Bold An obstruction allowance shall be applied in critical areas where excessive backwater may result in property damage or be a potential safety hazard. After using the appropriate design methodology to calculate the peak stormwater flow for a given frequency, an obstruction allowance will be added to the peak flow to establish the design flow rate through the culvert. The minimum obstruction allowance factor is intended to account for normal culvert obstructions, which may lower the actual capacity of the culvert once constructed, and is based on the size of the culvert pipe in accordance with the following tabulation: Culvert Size Minimum Obstruction Allowance Factor 18" and less 25% 21"-24" 20% 30" 15% 36" and greater 10% COUNTY OF ROANOKE ;444x/1/16 6-2 CULVERTS CULVERTS 6.2.3 Culvert Hydraulics CHAPTER 6 ,A._ Design Flow Formatted: Font: Bold The design flow shall be the peak flow from the following frequency storm event, plus the appropriate obstruction allowance: Roadway Storm Frequency Primary & Arterial 25 -year Secondary & Other 10 -year These frequencies are minimum values. Designing for less frequent storms may be required where there is potential damage to structures, loss of human life, injury, or heavy financial loss in the event of flooding. Compliance with the National Flood Insurance Program (NFIP) is necessary for all locations where construction will encroach on a 100 -year frequency flood plain. In addition, the 100 -year peak flow (without the addition of the obstruction allowance) shall be routed through all culverts, determining the headwater depth behind the culvert with road overtopping, to ensure that buildings and other structures are not flooded and that adjacent roadways and adjacent properties do not suffer significantly increased damage during the 100 -year storm event. Storage impacts of water behind the culvert may be considered in the calculation, but is not required. - - Formatted: Indent: Left: 1.5", First line: 0.5" ._Allowable Headwater Formatted: Font: Bold The allowable headwater is the depth of water that can be ponded at the upstream end of the culvert during the design condition, as measured from the culvert inlet invert. The allowable headwater depth shall be limited by the following conditions: • Headwater does not cause upstream property damage; • Headwater does not increase the 100 -year flood elevation, as mapped by NFIP; • During a design storm event, the water surface shall be a minimum of 18 inches below the shoulder of the road at the point where the culvert crosses COUNTY OF ROANOKE ;444x/1/16 6-3 CULVERTS CULVERTS CHAPTER under, or the low point of the road grade where the water would overtop the road; • Headwater depth shall not exceed 1.5 times the diameter or height of the culvert barrel; • Headwater depth shall not be such that stormwater flows to other ditches or terrain, which permits the flow to divert around the culvert. • The maximum overtopping depths during an 100 -year storm event for various street classifications are as follows: Classification Max. Depth at Crown Max. Velocity Local 1 ft* 6 fps Collector 1 ft* 6 fps Arterial No Overflow No Overflow Highway No Overflow No Overflow * Street overflow during a 100 -year storm will not be allowed if the street is the only means of access for 40 or more residences. A variance to this requirement may be granted if the applicant shows that the connecting roads will be experiencing substantial overtopping during a 100 -year storm and that there is no benefit to enforcing this requirement. • In most instances, the roadway overtopping may be treated as a broad crested weir. ,C._ Tailwater Conditions Formatted: Font: Bold Tailwater is the water into which a culvert outfall discharges. Culvert design shall be based on tailwater conditions that could reasonably be anticipated during the design condition. • If an upstream culvert outlet is located near a downstream culvert inlet, the headwater elevation of the downstream culvert may establish the design tailwater depth at the upstream culvert. • If the culvert discharges into a lake, pond, stream, or other body of water, the maximum water elevation of the body of water during the design storm may establish the design tailwater elevation at the upstream culvert. COUNTY OF ROANOKE ;444x/1/16 6-4 CULVERTS CULVERTS CHAPTER Inlet and Outlet Control - Formatted: Font: Bold Culvert hvdraulic design shall consider both inlet and outlet control conditions. For a culvert operating with inlet control, the flow capacity is governed by the inlet geometry. For an outlet control culvert, the inlet geometrv. barrel characteristics and tailwater elevation all impact the flow capacity. Minimum culvert performance is determined by analyzing both inlet and outlet control for a given flow and using the highest resulting headwater. (i) Inlet Control - I Formatted: Underline The following factors are considered when calculating inlet control headwater: • Inlet Area — cross sectional area of the culvert entrance face • Inlet Edge — projecting, mitered, headwall, or beveled edges are common • Inlet Shape — rectangular, circular, elliptical, or arch are common The nomograph for inlet control for circular concrete, corrugated metal and corrugated HDPE culvert pipe is included in Appendix 6A. Nomographs for calculating headwater and flow capacity for other pipe geometries are contained in the VDOT Drainage Manual. ,(ii) Outlet Control - I Formatted: Underline The following factors are considered when calculating outlet control headwater: • Manning's Roughness (n) — based on barrel material, for recommended n values, see the table in Appendix 6A. • Barrel Area — cross section perpendicular to the flow • Barrel Length • Barrel Slope COUNTY OF ROANOKE ;444x/1/16 6-5 CULVERTS CULVERTS CHAPTER 6 • Tailwater Elevation Outlet control affects the hydraulic grade line of the flow through the culvert. To calculate the hydraulic grade, reference the equations for velocity, velocity head, entrance losses, friction losses, and exit losses contained in the VDOT Drainage Manual. The nomograph for outlet control on circular concrete and corrugated metal pipe is included in Appendix 6A. For additional nomographs, cross sections, and pipe materials, see the VDOT Drainage Manual. Formatted: Font: Bold E. Culvert Velocity Outlet velocity must be checked to assure that excessive erosion and scour problems will not occur. MS 19 from the VA E&SC Handbook requires that discharges be made to an adequate channel. Culvert outlet protection shall be provided in accordance with the standards and specifications for Outlet Protection and Riprap in the VA E&SC Handbook. Culverts under roads shall be provided with end sections or endwalls in accordance with the outlet protection requirements of the VDOT Drainage Manual. Where a special design is needed to reduce outlet velocity, it shall be designed in accordance with VDOT standards. The minimum velocity in a culvert barrel must be adequate to prevent siltation at low flow rates. At a minimum this velocity shall be 3 feet per second for a 2 -year storm event. 6.2.4 Structural Design All culverts shall be designed to withstand a HS -20 highway loading, unless it crosses under a railroad, in which case the culvert shall be designed for railroad loads. The structural design shall consider the depth of cover, trench width and condition, bedding type, backfill material, and compaction. 6.2.5 Materials Culverts, both public and private, shall be constructed of materials as follows: COUNTY OF ROANOKE ;444x/1/16 6-6 CULVERTS CULVERTS CHAPTER • Culverts in the VDOT right-of-way shall be VDOT approved materials in accordance with VDOT IIM-LD-121.15 and VDOT Standard PC -1. Minimum depths of cover are shown in the PC -1 details. • Public culverts not in the VDOT right-of-way shall be: o Reinforced concrete pipe (RCP) Class III minimum or greater as required by loading conditions/cover or box. o Aluminized corrugated metal pipe (CMP), is allowed for private systems only for sizes 36 -inch diameter or smaller. Minimum gage thickness for CMP culverts shall be 16 gage for 30 -inch diameter and smaller. Minimum gage thickness for 36 -inch diameter CMP culverts shall be 14 gage. Trench design for CMP culverts shall meet ASTM or AASHTO standards. o Special CMP culverts including diameters greater than 36 -inch, elliptical, and arch designs will be considered on a case-by-case basis by the County of Roanoke for use as culvert pipe material in private storm drain systems. • Private culverts not in the VDOT right-of-way may be: o Reinforced concrete pipe (RCP) Class III minimum or greater as required by loading conditions/cover or of box. o Aluminized corrugated metal pipe (CMP), for sizes 36 -inch diameter or smaller. Minimum gage thickness for CMP culverts shall be 16 gage for 30 -inch diameter and smaller. Minimum gage thickness for 36 -inch diameter CMP culverts shall be 14 gage. Trench design for CMP culverts shall meet ASTM or AASHTO standards. o Special CMP culverts including diameters greater than 36 -inch, elliptical, and arch designs will be considered on a case-by-case basis o Corrugated high-density polyethylene (HDPE) with an integrally formed smooth interior is allowed for sizes 48 -inch diameter or smaller. HDPE culvert pipe minimum cover must be in accordance with the County of Roanoke Inspection Specifications for HDPE Pipe contained in Chapter 7-13- 11. COUNTY OF ROANOKE ;444x/1/16 6-7 CULVERTS CULVERTS 6.2.6 Culvert Sizes CHAPTER 6 The minimum culvert size shall be 18 -inch diameter, except that culverts under private entrance roads or driveways may be 15 -inch diameter if it meets all design flow conditions. Culverts shall meet all cover conditions required. Where the site conditions preclude the use of a single culvert barrel to meet the design flow conditions, multiple barrel culverts are acceptable. The maximum length of a culvert shall be 300 feet. A culvert longer than 300 feet shall have manholes or junction boxes and shall fall under the requirements of Chapter 7. 6.2.7 End Conditions End sections and headwalls shall normally be required on inlets and outlets, as described below. �1. Prefabricated End Sections Formatted: Font: sold —Prefabricated end sections, or flared end sections, provide for a better flow path, improving the design flow and headwater conditions. Prefabricated end sections shall be provided for culverts 18 -inch to 36 -inch diameter, except: • No end section is required for 15 -inch or 18 -inch diameter driveway culverts. • Where culvert alignment exceeds 20 feet in vertical elevation change or culvert slope exceeds a 2:1 slope, a standard concrete headwall shall be provided instead of a prefabricated end section. • Where a concrete headwall is provided. J._ Concrete Headwalls and Structures - - I Formatted: Font: sold Precast concrete headwalls shall be provided at all culvert inlets and outlets, unless other end conditions are allowed, as stated above. Precast concrete headwalls shall meet the requirements of the VDOT Standards and VDOT Specifications. COUNTY OF ROANOKE ;444x/1/16 6-8 CULVERTS CULVERTS CHAPTER Wingwalls may be required in conjunction with headwalls. Culvert pipes 48" or larger in diameter shall have concrete wngwalls. Wingwalls are generally used where the culvert is skewed to the normal channel flow or where the side slopes of the channel or roadway are unstable. Wingwalls shall meet the requirements of the VDOT Standards and VDOT Specifications. Wing walls shall be set at an angle between 30 degrees and 60 degrees from the headwall. Concrete aprons may be used at the entrance or the exit of culvert. Aprons are typically used where high velocities or headwater conditions may cause erosion upstream or downstream of the culvert. An apron shall not protrude above the normal stream bed elevation. Special design concrete slab end treatment, per VDOT Standards, may be used as a concrete end section. 6.2.8 Multiple Barrel Culverts Multiple barrel culverts shall be allowed where single culverts cannot handle the design flow while meeting the required cover or headwater condition requirements. The design of multiple barrels should avoid the need for excessive widening of the upstream or downstream receiving channels. The minimum spacing between culverts in a multiple barrel culvert design shall be that required to provide adequate lateral support and allow proper compaction of bedding material under the pipe haunches. 6.2.9 Culvert Skew Where possible, culverts shall be installed parallel to the flow path. The maximum allowable skew shall be 45 degrees as measured from the line perpendicular to the roadway centerline. 6.2.10 Buoyancy Verify that culvert pipe, end sections, and concrete end wall structures will not fail under hydrostatic uplift conditions. Buoyancy force consists of the weight of water displaced by the pipe and fill material that is over the pipe (below the headwater depth). The force resisting buoyancy includes the weight of the pipe, weight of the water within the pipe, and the weight of fill material over the pipe. Buoyancy is more likely to be a problem where: COUNTY OF ROANOKE ;444x/1/16 6-9 CULVERTS CULVERTS CHAPTER 6 Lightweight pipe is used Pipe is on a steep slope (usually inlet control with the pipe flowing partially full) • There is little weight on the end of the pipe (flat embankment slopes, minimum cover, and/or no endwalls) • High headwater depths (HW/D>1.0) Suitable cover, footings, or anchor blocks may be required to ensure the culvert's integrity during design conditions. 6.2.11 Debris and Trash Racks In general, trash racks or debris deflectors shall not be used where other site modifications may be made to prevent excessive trash or debris from entering the culvert. However, they may be required at specific locations, by the County of Roanoke, where large amounts of storm debris may be anticipated. 6.3 Installation All culvert pipe, headwalls, end sections, outlets, and other peripheral structures shall be installed in accordance with VDOT requirements and the manufacturer's recommendations. The characteristics of the trench, bedding, and pipe material all impact the structural strength of the pipe system. The installed culvert conditions shall comply with the design assumptions and calculations. HDPE pipe installation shall comply with the County of Roanoke's Inspection Specifications for HDPE Pipe. A copy of this installation guide is provided in Chapter 7. 6.3.1 Bedding Material Bedding material and installation shall comply with the requirements of the VDOT Specifications. 6.3.2 Backfill Backfill shall be suitable material and shall be placed and compacted in accordance with VDOT Specifications. A minimum of 12" backfill shall be placed over the top of a HDPE or CMP .- - - Formatted: indent: Left: r', First line: 0" culvert prior to placing pavement or other surface treatment. COUNTY OF ROANOKE ;444x/1/16 6-10 CULVERTS CULVERTS CHAPTER 6.4 Environmental Considerations and Fishery Protection Where compatible with good hydraulic engineering, a culvert shall be located in "dry" conditions. Where this is not possible, the culvert shall be located to minimize impacts to streams or wetlands. When a culvert is set in a perennial stream the invert of the culvert shall be set below the normal flow line of the stream as required in the VDOT Drainage Manual. The grade of the culvert shall not exceed the grade of the natural stream in the area. Where construction requires other environmental permits, the applicant shall be responsible for obtaining all necessary environmental permits and complying with their requirements. 6.5 Maintenance Requirements The permittee is responsible for maintenance of culverts until construction is complete, including final clean up and site stabilization, to the satisfaction of the County of Roanoke. After the completion of construction, the property owner or responsible party is responsible for maintenance of all culverts not located in public easements. No one shall modify culverts in any way that impairs or restricts flow. The property owner shall periodically remove silt and sediment from the pipe and prune vegetation around the pipe entrance to avoid restricting flow capacity and shall correct erosion damage as necessary. All removed silt and sediment shall be properly disposed of away from storm drainage pipes and open channels and shall be properly stabilized with vegetation. COUNTY OF ROANOKE ;444x/1/16 6-11 CULVERTS CULVERTS APPENDIX 6A AIDS FOR STORMWATER CULVERT DESIGN FROM CHAPTER 8, VDOT DRAINAGE MANUAL APPENDIX 6A Appendix 813-1, Culvert Design Form LD -269 Appendix 8C-1, Nomograph for Inlet Control for Circular Concrete Pipe Appendix 8C-2, Nomograph for Inlet Control for Corrugated Metal Pipe Nomograph for Inlet Control for Corrugated HDPE Pipe Note: This table is not from the VDOT Drainage Manual. Appendix 8C-4, Nomograph for Critical Depth, Circular Pipe Appendix 8C-5, Nomograph for Outlet Control for Circular Concrete Pipe Appendix 8C-6, Nomograph for Outlet Control for Corrugated Metal Pipe Appendix 8D-1, Recommended Manning's n -Values Note: This table has been modified from VDOT's standard to include additional pipe materials. Appendix 8D-2, Entrance Loss Coefficients (Ke), Outlet Control, Full or Partly Full COUNTY OF ROANOKE ;444x/1/16 6A-1 CULVERTS CULVERTS APPENDIX 6A CULVERT DESIGN FORM (VDOT LD -269) COUNTY OF ROANOKE ;444x/1/16 6A-2 CULVERTS i LL 3■■0r n ■ .■.■�■■■■■� r■.■■■.■■■E �■■■ on • ■■■■E■.■■■■ I■■■■�■■ ■■■■■■■■■E .■■■.■■■■■.IMEMEMEMEMME [monsoon .■.■.■.■ ■■. 11,10MMEM ■®��■■ .mommmmommill ■■■.■■■■■. ..■..■■■■■. .. E■.■■■■■. IMEMBEEMEMER .■■.■■■■■■. .■■■■■■.■■.r ............ ■■■■■■■■■■�■■■■■� i-■■■■■■ MENOMONEE .■■ ■ ■■■■■■.. ■�■, MIME■■■■MINEENEEMBEE `■�■�■■.■ IMM■■■■■MINME■■�■■■.'. MM.■M■..l y ■■■.■■.., ......,l1 , - ■■■■■■.., . ■■■.■■A.. ■■■.■■EZ, 7 COUNTY OF ROANOKE ;444x/1/16 6A-2 CULVERTS CULVERTS Il` APPENDIX 6A TLET CONTROL, CIRCULAR CONCRETE PIPE CHART 1 Mo Me $r000 EXAMPLE {3} 666 p..! i.e■ae 144 ::m s.ao0 a req.h. }E 4,04q ■ * 6• S. 5.000 Ir.� .y 4. �eY ili S,3 i.�1 4. 2,001D 4.. X66 [tl9 t.t 7.h - 3. �4 Ip PNl �• 96 1 aU0 3. Boo 64 Baa --� -- - t- 900! it 400 !. 3b0 �." I,q Y.3 elp u Pca 1.0 z � �- 54 / = x 40 100 q Ba — r 42 —60 06 110 Fp W- EMTR AIi GE ca 40 4a SGALE TTPE tlt I-0 36 'Jq {11 sy..n.ra .er■ r 9 .$ S3 F.eex.p � ea .9 t'0 #I pram. ■r■.i�. W 30 e..■..0 ; .4 :4 tr .r■]Ie7W is 24 � 7. w. ■e■la lel •e p} h�l1.e� 41 S ■ne lea.+e!4 .a .s■M [15. ihp 4 ...Irel*hE farWny iY.. 1M.np pF.n1 0 iie..e•ar ray.rn a. 6 3 Wl..ir.1.4 .8 ]e r i6 1.0 .a B L Y4 HEADWATER DEPTH FOR rEkGWiRE11SCALES 2BB CONCRETE PIPE CULVERTS ■u.e.uww.LICWPM a.,w.OU aErisED MAY 934 WITH INLET CONTROL COUNTY OF ROANOKE ;/444x/1/16 6A-3 CULVERTS CULVERTS APPENDIX 6A INLET CONTROL, CIRCULAR CORRUGATED METAL PIPE 0 CHART 2 Ie9 X0,400 Is! 8,000 EXAMPLE II) ISB 6,994 m• Si l s... [e.a fNfl 6 ILl '5,000 a•44.H 144 4,000 r R MR 13@ 3,000 0-46 4. Ito i11 I,f f.4 -2,000 m ioe tel !.s 6.0 4• 4. 96 1,009 3. T3 000 S. 1 e4 q 600 1400 S90 1{ 7E . 300 is 800 4 60 h I W � 54 Q W � W 140 l S 7 40 c 60� O J 0, 60 x 42 60 l.0 I.0 -�N a � 40 y4j i.0 F 36 30 1!W ENTFCAN9E ¢ W p SCALE TYPE La o 33 29 N4.d.N1 30 121 Mil.nd to 0..10'.e � ,e I. M.P. ra 87 14 4'+I 1`16146o1.f a e a 84 F 6 .7 w 3 fp un mtr 12) w (31 rm}..r @i T' .e 4 ..n ... t.rlr t. s.4l. I,}, I►.n rM rU.14h1 in Glln4d Ilrr t.r..'k •6 ] 0 ..d 0 re.lr., tr ..'I.eN rl 6 iii nir.r..l.d. Z l 1,9 S HEADWATER DEPTH FOR C. M. PIPE CULVERTS WITH INLET CONTROL WPEAU W Pu9Ll 11 A03 -41"5 COUNTY OF ROANOKE ;444x/1/16 6A-4 CULVERTS CULVERTS APPENDIX 6A INLET CONTROL, CIRCULAR HDPE PIPE COUNTY OF ROANOKE ;444x/1/16 6A-5 CULVERTS �c_ard� t�} 6. 4. D- 36Artles'30feel) 6 44,000HOr C] 4, - 66 CIS HW 5 3J ,49318 D (leer) 200 i1 1.3 5.4 (2) 2:' 6.3 4 ,3) 22 6.6 3 a 1=0 .D in t£!Qt � BOO 3 540 S�41 4DO S 2 T ' __ EXAMPLE 1,5uj 54 cc 48 UlToo '.. /� cd L 7� C' 'te Hier d =u'GALe 40 D Tv / { /}} i��. dEvmp 11 f 3 # 30 . . # {2} MOlare d to 33 20 cmfarm to slope Lu 08 0. 3 � l31 i�rrsj�etin� � p 4.#3 L U_7' 43.2 24 = g p_7 3Ta use scale i2l ;2lOr 3) prajacl x, e. hotizovla!ly to stela � t ), thel use straight inclined lime th•augh 6.6 18 D and 0 =a!ec, or revarse as 2 itusttal. is 4 ry 10 U.5 HEADWATER DEPTH FOR e2 CORRUGATED HDPE CULVERTS WITH INLET CONTROL COUNTY OF ROANOKE ;444x/1/16 6A-5 CULVERTS CULVERTS CRITCAL DEPTH, CIRCULAR PIPE CHART 4 9 r w W x 6 W 6 J Y 61 APPENDIX 6A '.I I I i I I do CAMNQT ixMID Tor W P5t x 9 �4 912 39 dko 50 60 70 00 •G 11212 41§CFliTiGE• 9 - GF9 w W O r r YI O J d �4 �i}0 204 'J9G 49D 5129 699 F912 499 999 F9nC 615CNARCE -9-OF S a] r ■■MENo N■NEM■i■■■■■o s• ■■■■■ DISCHARGE - 9. GFS BUREAU Of PUML14 ROADS DAPI. 194i4 CRITICAL DEPTH CIRCULAR PIPE COUNTY OFROANOKE ;444x/1/16 6A-6 CULVERTS CULVERTS APPENDIX 6A OUTLET CONTROL, CIRCULAR CONCRETE PIPE 7 2404 nw I CCpO C = J 511l LR�GiG OYi LlT 04eyENT FtAwni ryL� .S Y00 YR4 f�r w+err �r rol •Ly/� I+weUM Y N �' lw�N SU4 '36 F yam' l9 400 $04 - T! 2 800 60 4fi W - W 9 �r—'�.`�— ti z 3 cy IOO T Ll i ±t + �•� a yp ry -4 moll 9 1- A $ d 0 40 W bQ txp' a • Q .l 10 20 tl 120 Ya 0 ES Y g Y9 9 4 hEAD FOR CONCRET1= PIPE CULVERTS FLOWING FULL WA -0f O-LSLIC F&*DS 4++1. per} n m 0 0 12 COUNTY OFROANOKE ;444x/1/16 6A-7 CULVERTS CULVERTS APPENDIX 6A OUTLET CONTROL, CIRCULAR CORRUGATED METAL PIPE r 2000 800 b boo 400 Too b! $90 800 *0 400 b! 300 64 400 12 4i 40 44 '00 w x 4■ 40 x 42 as s 50 0 34 40 33 30 Y~l 8£ 30fq� q t 27 d 20 Y4 10 0 a �a s 4 3 R IMMM OF IMALIL IpiO4 ,MN. 1415 W"EKGEO OUTLET CULVERT FIJWIgfi FULL !x P.M erirn. MA wii..".4. —pw. Mw YF _! w11M14 Mi"$ M 1% 41144. V"14.rf LO Q�e +y° O� fp W W e° TJy = Od r. S 3 00 t 4 J •00 40q �o to HEAD FOR STANDARD C. M. PIPE CULVERTS FLOWING FULL n = 0.024 COUNTY OFROANOKE ;444x/1/16 6A-8 CULVERTS CULVERTS APPENDIX 6A OUTLET CONTROL, CIRCULAR CONCRETE PIPE RECONIWNDED MANNING'S n -VALUES Type of Conduit Wall Description Manning's n Concrete Pipe Smooth walls 0.010 - 0.013 Concrete Boxes Smooth walls 0.012 - 0.015 Corrugated Metal 2 2/3 by 'h inch 0.022 - 0.027 Pipes and Boxes, Annular or corrugations Helical Pipe 6 by 1 inch 0.022 - 0.025 corrugations 5 by 1 inch 0.025 - 0.026 corrugations 3 by 1 inch 0.027 - 0.028 corrugations 6 by 2 inch 0.033 - 0.035 structural plate 9 by 2'h inch 0.033 - 0.037 structural plate Corrugated Metal 2 2/3 by 'h inch corrugations 0.012 - 0.024 Pipe Spiral Rib Metal Smooth walls 0.012-0.013 (Steel or Alum.) PVC Smooth interior 0.010 - 0.012 Polyethylene (PE or HDPE) Smooth interior 0.011 - 0.013 Corrugated PE or HDPE Corrugated interior 0.022 - 0.026 Note 1:The values indicated in this table are recommended Manning's "n" design values. Actual field values may vary depending on the effects of abrasion, corrosion, deflection, and joint conditions. Concrete pipe with poor joints and deteriorated walls may have "n" values of 0.014 to 0.018. Corrugated metal with join and wall problems may also have higher "n" values, and in addition, may experience shape changes which could adversely affect the general hydraulic characteristics of the culvert. Note 2:Fore further information concerning Manning n values for selected conduits consult Hydraulic Design of Highway Culverts, Federal Highway Administration, HDS No. 5, page 163. COUNTY OF ROANOKE ;444x/1/16 6A-9 CULVERTS CULVERTS APPENDIX 6A ENTRANCE LOSS COEFFICIENTS (Ke) OUTLET CONTROL, FULL OR PARTIALLY FULL Type of Structure and Design of Entrance Coefficient Pipe, Concrete Mitered to conform to fill slope 0.7 End -section conforming to fill slope 0.5 Projecting from fill, square cut end 0.5 Headwall or headwall and wingwall Square -edge 0.5 Rounded (radius = 1/12 D) 0.2 Socket end of pipe (groove end) 0.2 Projecting from fill, socket end (groove end) 0.2 Beveled edges, 33.7° or 45° bevels 0.2 Side or slope -tapered inlet 0.2 Pipe, Corrugated Metal (or Corrugated HDPE) Projecting from fill (no headwall) 0.9 Mitered to conform to fill slope, paved or unpaved slope 0.7 Headwall or headwall and wingwall, square -edge 0.5 End section conforming and to fill slope 0.5 Beveled edges, 33.7° or 45° bevels 0.2 Side or slope -tapered inlet 0.2 Box, Reinforced Concrete Wingwalls parallel (extension of sides), 0.7 square edged at crown Wingwalls at 10° to 25° or 30° to 75° to barrel, square edged on 3 edges 0.5 rounded on 3 edges to radius of 1/12 barrel 0.2 Wingwalls at 30° to 750 to barrel, crown edge rounded to radius 1/12 of barrel 0.2 Side or slope -tapered inlet 0.2 Note: End Section conforming to fill slope made of metal, concrete, or HDPE, are the sections commonly available from manufacturers. From limited hydraulic test they are equivalent in operation to a headwall in both inlet and outlet control. Some end sections incorporating a closed taper in their design have a superior hydraulic performance. These latter sections can be designed using the information given for the beveled inlet. COUNTY OF ROANOKE ;444x/1/16 6A-10 CULVERTS STORM DRAINS Chapter 7 - Storm Drains CHAPTER 7 A storm drain is a drainage system that conveys water or stormwater, consisting of two or more pipes in a series connected by one or more structures. Storm drains collect and transport stormwater from a site primarily through the use of a closed pipe network. For the storm water to be efficiently handled in a storm drain, the site must also have an efficient way to collect stormwater runoff and have it enter into the piped network. Once in the storm drain, the stormwater is routed to a discharge outfall. Storm drain systems include: Measures to get stormwater runoff to inlets, Inlets, and s1Storm drain pipiftgpipes and structures that stormwater runoff must pass through to reach the outfall This section defines criteria and restrictions that shall be used in designing and constructing public and private storm drains. See the VDOT Drainage Manual for more in-depth information. All storm drains 12 inches in diameter and larger shall have profiles prepared and submitted to the County. 7.1 References Except where more stringent requirements are presented in this Manual, storm drain collection systems shall comply with VDOT and other state requirements. The primary design reference is the VDOT Drainage Manual. Other appropriate references include: • VDOT Standards • VDOT Specifications • VA E&SC Handbook • FHWA Drainage of Highway Pavements HEC No. 12. • FHWA Urban Drainage Design Manual HEC No. 22. • VA Stormwater Management Handbook, Chapter 6 Appendix 6B (Karst Guidelines) COUNTY OF ROANOKE q444x/1/16 7-1 STORM DRAINS STORM DRAINS CHAPTER 7 7.2 Design Methodology and Criteria 7.2.1 Computation Methods Manual computations use design equations and nomographs. Results are documented on VDOT work sheets. Copies of these forms are included in Appendix 7A. • Form LD -204 Stormwater Inlet Computations • Form LD -229 Storm Drain Design Computations • Form LD -347 Hydraulic Grade Line Computations There are a number of computer programs available to design storm drainage systems. Any of these computer programs will be acceptable if their methodologies are based on the same equations and nomographs accepted by VDOT, and if they provide the same documentation of inputs, assumptions, and output as are contained on VDOT's work sheets. Computation methods are explained in detail, including comprehensive design examples, in the VDOT Drainage Manual. 7.2.2 Hydrology ,A._ _ _ Design Flow Methodology Formatted: Font: Bold Calculations establishing the design flow shall be submitted with the Stormwater Management Plan. Design flows shall be based on ultimate build -out of the contributing watershed based on the current Comprehensive Plan. 7.2.3 Design Flows The following minimum storm frequencies shall be used: A._Inlets ------------------------------------------ Formatted: Font: Bold Inlets shall be designed for storm frequencies and intensities consistent with the VDOT Drainage Manual. For reference, the VDOT table and its accompanying notes have been included in Appendix 7A. COUNTY OF ROANOKE q444x/1/16 7-2 STORM DRAINS STORM IMAINS CHAPTER 7 J._-- Storm Drains ----------------------------------- Formatted: Font: Bold Storm drains shall be designed for the storm frequencies and intensities consistent with the VDOT Drainage Manual. For reference, the VDOT table and its accompanying notes have been included in Appendix 7A. Unless otherwise specified by the VDOT Drainage Manual, a 10 -year frequency design storm shall be used in developing design flows. 7.2.4 Measures to Convey Stormwater Runoff to Inlets ,A._ Pavement Drainage _ _ _ _ Formatted: Font: Bold One objective in the site design is to collect and remove stormwater runoff from critical areas as efficiently as possible. A properly designed system will ensure that roadway surfaces are free of stormwater accumulations, and will protect the public from unnecessary hazards associated with water ponding and sheet flow. Except where porous pavement is used, road pavement shall be sloped transversely to drain stormwater from the roadway. A minimum cross slope of 2 percent should be applied to all roads, both primary and secondary. Greater slope should be considered where poor drainage is anticipated. Drainage structures associated with medians, curbs, and gutters should be designed to minimize accumulation of water onto travel lanes of roadways. For additional information concerning drainage of highway pavements, refer to FHWA HEC No. 12. J1 Curb and Gutter Formatted: Font: Bold Curb and gutter at the edge of pavements may be used to collect stormwater runoff from roadways. Curbing captures stormwater runoff and directs it to stormwater collection inlets while protecting adjacent properties from flooding and erosion due to sheet flow runoff from the impervious roadways. A curb and gutter forms a triangular conveyance channel. When a storm occurs, the runoff from the road creates a spread of water from the curb. The curb and gutter must be designed to convey this flow and prevent the COUNTY OF ROANOKE q444x/1/16 7-3 STORM DRAINS STORM DRAINS CHAPTER 7 spread of water from impacting traffic. The spread width of flow is determined by using VDOT nomographs or acceptable hydrological design software. For curb and gutter flow, a Manning's n value of 0.015 is used in the computational analysis. See Appendix 7A for width of maximum allowable spread. Curb and gutter dimensions and design shall meet VDOT Standards. - C._ -Open Channels------------------------------------- Formatted: Font: Bold Open channels may be used to collect site drainage and convey it to a storm drain inlet. Design requirements for open channels are covered in Chapter 5. 7.2.5 Storm Drain Inlets A. General --------------------------------------- Formatted: Font: Bold Storm drain inlets are used to collect stormwater runoff from roads, walks, or low elevations during storm events and provide a method for passing the stormwater into the storm drain system. This is usually accomplished by placing storm drain inlets at regular intervals, low points, or at key locations to intercept flows and control the stormwater spread width. The design criteria for limiting the spread of water on travel lanes are contained in the VDOT Drainage Manual. The current design table and its notes have been included in Appendix 7A There are several different types of storm drain inlets which can be used to meet this purpose, and the designer shall choose the proper inlet structure based upon site conditions and design conditions to maximize the drainage efficiencies. • Curb • Grate • Slotted Drain/Trench • Combination Drainage and Stormwater management plans shall include a contour plan with sufficient contours shown to indicate proper drainage. B. `Curb Inlets - I Formatted: Font: Bold COUNTY OF ROANOKE q4114x/1/16 7-4 STORM DRAINS STORM DRAINS CHAPTER 7 Curb inlets are vertical openings in the curb covered by a top slab. These inlets can convey large quantities of water, but also allow for large amounts of debris to enter the storm drain system. Curb inlets shall be used to the maximum extent possible for pavement drainage. C. Grate _Inlets _ _- Formatted: Font: Bold Grate inlets are horizontal grates usually used in depressed medians or other low elevations. Grate inlets are often referred to as drop inlets or DIs. Grate inlets shall be avoided in paved areas. Where they are used in pavement, inlet grates shall be bicycle safe. D. Combination Inlets ------------ I Formatted: Font: Bold Combination inlets combine both the vertical opening used by curb inlets and the horizontal grate used in grate inlets. These inlets are often used when the inlet chamber is required to be under the gutter or street pavement away from the sidewalk or other utilities. Combination inlets shall be avoided where possible. Where they are used, they shall have bicycle safe grates. E. Slotted Drain Inlets _ _- Formatted: Font: Bold Slotted drain inlets are a narrow slotted opening which can collect flow at a median barrier or curb. These inlets are usually located in areas of limited space and can be used to intercept sheet flow, or collect gutter flow to help reduce ponding depth or spreading at grate inlets. F. jnlet Locations - - I Formatted: Font: Bold Inlets shall be located to meet the design requirements of the VDOT Drainage Manual for maximum spread width. In addition, inlets shall be provided, regardless of contributing drainage area as follows: • Sag points in the gutter grade; • Upstream of median breaks, crosswalks, and street intersections; • Immediately upstream and downstream of bridges; COUNTY OF ROANOKE q444x/1/16 7-5 STORM DRAINS STORM DRAINS CHAPTER 7 • On side streets at intersections, where flow is approaching the main line; • Behind curbs, shoulders, or sidewalks to drain low areas or intercept concentrated flow; and • Any low elevation in the grade. Inlets shall be avoided in pathways likely to be used by pedestrians or bicyclists. $G. Access --------------------------------------- Formatted: Font: Bold All inlets shall have a removable grate or manhole cover to allow access for clean out. All structures greater than 3 feet in depth shall be a minimum of 4-1 feet in diameter for maintenance access. CH` Inlet Capacities Formatted: Font: Bold The capacities of each inlet type are contained in the VDOT Drainage Manual. Documentation of inlet capacity shall be made on VDOT Form LD -204, Stormwater Inlet Computations or equivalent. JII.__ Separation of Pipes in Inlets---------------------------- Formatted: Font: Bold Where two or more pipes enter a concrete structure at or near the same elevation, a 6" minimum horizontal clearance must be maintained between the pipes. Additional clearance between pipes shall be provided if required to protect the structural integrity of the structure. P. Karst Terrain - I Formatted: Font: Bold Water tight joints are required where storm drainage pipe are located in karst terrain. Additionally, an A -lock premium gasket or boot is required for the pipe connection to the storm drainage structure to prevent water loss at the structure connection. 7.2.6 Storm Drain Pipes ,A.___ Flow Capacity----------------------------------- - Formatted: Font: Bold COUNTY OF ROANOKE q444XI1/16 7-6 STORM DRAINS STORM DRAINS CHAPTER 7 Based on the size and slope of the storm drain, the design capacity for a pipe flowing full can be determined using Manning's equation. Q=Ax1.49/nxW"xS"2 Where: Q = Flow in the pipe (cfs) A = Area of the pipe (ft) R = Hydraulic radius, for circular pipe R=Diameter/4 (ft) S = Storm drain slope (ft/ft) n = Pipe roughness coefficient The design flow capacity of a storm drain shall comply with the design frequencies set forth in VDOT Drainage Manual as shown in the table in Appendix 7A. In a roadway underpass, or depressed section, where ponded water can only be removed through the storm drain system, a 100 - year frequency storm event shall be used to design the storm drain at the sag point. Storm drain flow capacities shall be documented on VDOT Form LD -229, Storm Drain Design Computations or equivalent form. J1 Storm Drain Slope ..... Formatted: Font: Bold To deter the settling of debris and sediment in the storm drain pipe, the pipe shall be designed to ensure positive slope and maintain a minimum velocity of 3 feet per second during a 2 -year frequency storm or a minimum of 0.5% slope, whichever is more restrictive. A minimum drop across the structure of 0.1' shall be provided in all storm drainage structures. The maximum pipe velocity io-in any storm drain shall be in , - Formatted: Subscript accordance with VDOT requirements based on the storm drain material, but in no event shall it be greater than 20 fps. Storm drains shall be sloped to meet the velocity requirement set in this chapter. Slopes greater than 16 percent shall be avoided if possible. If unavoidable, drop structures shall be utilized in steeper terrain. In addition, storm drains with slopes steeper than 16% must have anchor blocks for support. `C'_ --Pipe Size ----------------------------------------- Formatted: Font: Bold COUNTY OF ROANOKE q444x/1/16 7-7 STORM DRAINS STORM DRAINS CHAPTER 7 All storm drains located in public easements or rights-of-way shall be a minimum of 15 -inch diameter. Pipe size shall not be reduced along the direction of the flow, except as required for proper operation of stormwater management facilities. p.- --Access - ----------------------------------------- Formatted: Font: Bold Regardless of pipe size, a cleanout access point, either an inlet, manhole, or junction box shall be provided at a maximum of every 300 feet of pipe. Cleanouts can be used for pipes 6" and smaller. All pipes over 6" require an inlet or manhole. JE. ---Joints ----------------------------------------- Formatted: Font: Bold At a minimum, all joints shall be "soil tight". The County strongly recommends the use of "water -tight" joints under pavements and areas that are stormwater "hotspots". "Water -tight" joints are required for karst terrain. See Section IV and corresDondine ADS detail in ADDendix 7B for additional info in water tight ioints 7.2.7 Determination of Hydraulic Grade Line A. General --------------------------------------- Formatted: Font: Bold The hydraulic grade line represents the free water surface elevation of water in a pipe system. Where the hydraulic grade line is above the top of a pipe, the pipe is flowing under pressure. The hydraulic grade line in a manhole or other structure is the elevation to which water will rise. Hydraulic grade lines shall be calculated and evaluated for all storm drains. The hydraulic grade line shall be calculated using VDOT methods and equations that are fully described in the VDOT Drainage Manual. Calculations shall be documented on VDOT Form LD -347, Hydraulic Grade Line Computations, or equivalent. A copy of this form is included in Appendix 7A. Hydraulic grade lines can also be calculated with design software (ie Storm sewer, etc.) The hydraulic grade line shall not exceed any critical elevation during the design storm. Critical elevations include rising above the ground COUNTY OF ROANOKE q444x/1/16 7-8 STORM DRAINS STORM DRAINS CHAPTER 7 elevation at inlets or other structures, or reaching an elevation where storm flow could back-up to cause flooding damage. The calculation of the hydraulic grade line begins at the system outfall and proceeds upstream to each structure on the system. The calculation is based on the principal of conservation of energy as shown below and includes major and minor energy losses: HGL„s= HGLd, + Hf+ Hm Where: HGL, = _ Elevation of hydraulic grade line at the upstream structure Hm = Summation of minor head losses (junctions, bends, etc.) Hf =_ Pipe friction loss HGLds Elevation of hydraulic grade line at the downstream structure Major head losses are attributable to friction losses within the pipe. Minor head losses include losses from: • Junctions • Exits • Entrances • Bends in Pipes • Access holes • Conflict pipes • Plunging flow • Expansions and contractions • Appurtenances such as weirs, diverters, valves and meters B. Outfall Conditions Formatted: Font: Bold The hydraulic grade line starts at the system outfall. At this point the hydraulic grade line shall be the actual tailwater elevation or the elevation of 0.8 times the diameter of the outlet pipe, whichever is higher. If the system discharges into a detention or retention pond, the hydraulic grade shall start at the 10 year water surface elevation. C. JPipe Friction Losses Formatted: Font: Bold The friction slope is the energy slope for that run of pipe. The friction slope is determined by inserting pipe information and design flow into COUNTY OF ROANOKE q444x/1/16 7-9 STORM DRAINS STORM DRAINS CHAPTER 7 Manning's equation and solving for S (slope). The total friction headloss in the run of pipe is the friction slope multiplied by the length of the run. Where the hydraulic grade line falls below the crown of the pipe, the elevation of normal flow is the hydraulic grade line. Formatted: Font: Bold D. Junction Losses J. General - I Formatted: Underline Junction head losses are the summation of entrance (Hi), exit (Ho), and bend losses (Ho). When calculating junction losses it is important to use actual flow velocities. If pipes are flowing partially full, then partially full velocities are used. 2. Entrance (expansion) Losses - I Formatted: Underline Entrance loss at a junction is given by: H;=K;(V,2/2g) Where: Hi= Entrance head loss Ki = Entrance loss coefficient. Ki = 0.35 Vi = Velocity in the inlet pipe. Where more than one inlet pipe - - Formatted: Indent: Left: 2" is present, use the velocity from the pipe that has the greatest momentum (Q*V) g =— Gravitational acceleration constant, 32.2 ft/s2 - - Formatted: Indent: First line: 0.5 3. Exit (contraction) Losses - I Formatted: Underline Exit loss at a junction is given by: Ho=Ko(V 0z/2g) Where: Ho= —Exit head loss Ko Exit loss coefficient. Ko = 0.25, except that Ko = 0.3 when - - Formatted: Indent: Left: 2" computing the loss leaving the initial inlet Vo = Velocity in the outlet pipe. - - Formatted: Indent: First line: 0.25' g = Gravitational acceleration constant, 32.2 ft/s2 COUNTY OF ROANOKE q444x/1/16 7-10 STORM DRAINS CHAPTER 7 4. JBend Losses - I Formatted: Underline Bend loss at a junction are dependent on the angle between the inlet and outlet pipes. If the inlet and outlet pipe are in line with one another no bend) the angle is 0 degrees and there is no bend loss. As the angle increases towards 90 degrees, the bend loss increases. Storm drain systems should not be designed with bend angles greater than 90 degrees. The bend loss is given by: Ho = K (V;z / 2g) Where: - - Formatted: Indent: Left: 1.75", First line: W - - Formatted: Indent: Left: 1.75", First line: W Ho = Head loss at bend K = Bend loss coefficient. K is determined by consulting Figure 9-10 in the VDOT Drainage Manual. A copy is included in appendix 7A. Vi = Velocity in the inlet pipe. g = Gravitational acceleration constant, 32.2 ft/s2 5. J!Iunging Losses - I Formatted: Underline Where surface inlet inflow is 20 percent or more of the total flow - - Formatted: Indent: Left: 1.75", First line: o" through a junction, or when a lateral pipe enters a junction with its invert elevation above the crown of the outgoing pipe and the flow in the lateral pipe is 20 percent or more of the total flow through the junction, the total headloss from the structure (Hi +Ho + Ho) shall be multiplied by 1.3 (increased by 30 percent). This adjustment is cumulative with the adjustment for inlet shaping. 6. Jnlet Shaping ------ I Formatted: Underline Inlet shaping refers to how the invert is shaped to provide smooth flow - - Formatted: Indent: Left: 1.75", First line: o" through the structure and is required in all manholes and inlets. When VDOT Standard IS -1, inlet shaping, is used in a structure the total headloss from the structure (Hi +Ho + Ho) shall be multiplied by 0.5 (decreased by 50 percent). This adjustment is cumulative with the adjustment for plunging losses. 7.2.8 100 -Year Conditions COUNTY OF ROANOKE q444x/1/16 7-11 STORM DRAINS STORM DRAINS CHAPTER 7 Where there is the possibility of building structures flooding, conditions during .- - - Formatted: Indent: Left: r', First line: 0" the 100 -year storm shall be analyzed to verify that all existing and proposed structures do not flood. Flow from the 100 -year storm may be carried overland as well as by the storm drain system. 7.2.9 Materials A. Structures --------------------------------------- Formatted: Font: Bold • All stormwater structures (inlets, manholes, and Junction boxes) F- - - Formatted: Indent: Left: 1.5", First line: 0", Bulleted + located in public easements or rights-of-way shall be recast or cast -in- Level: 1 +Aligned at: 0.75" +Indent at: r', Tab stops: p p 1.75", Left place concrete. All structures, frames, grates, and covers shall be in accordance with VDOT Standards and VDOT Specifications. - - Formatted: Indent: Left: 1", First Zine: 0" • All storm drain structures over four (4) feet in depth -must have steps. — - - Formatted: Indent: Left: 1.5", First line: 0", Bulleted + Level: 1 + Aligned at: 0.75" + Indent at: 1", Tab stops: 1.75", Left J1 Storm Drain Pipe - - I Formatted: Font: Bold • Storm drains in the VDOT right-of-way shall be VDOT approved materials in accordance with VDOT IIM-LD-121.15 and VDOT Standard PC -1. • Storm drains not in the VDOT right -of way shall be: o Reinforced concrete pipe (RCP). o Corrugated high-density polyethylene pipe (HDPE) with an integrally formed smooth interior is allowed for sizes 48 -inch diameter or smaller. HDPE pipe is allowed for pipe slopes less than 12% and with a velocity 12 fps or less. HDPE culvert pipe cover must be in accordance with the County of Roanoke Inspection Specifications for HDPE Pipe. A copy of this document is included in Appendix 713. - - Formatted: List Paragraph, Indent: Left: 1.81", No bullets o Culverts 60 inches in diameter or greater may be Corrugated or numbering, Tab stops: 1.56", Left Aluminized Metal Pipe (CAMP) or corrugated aluminum with a minimum 14 gauge metal. - - Formatted: List Paragraph, Indent: Left: 1.81", No bullets o The minimum cover for all pipes is two (2) feet measured from the or numbering, Tab stops: 1.56", Left final surface. Special applications for less than two (2) feet of cover COUNTY OF ROANOKE q444x/1/16 7-12 STORM DRAINS STORM DRAINS CHAPTER 7 will be reviewed and approved by the County Engineer individually. The maximum cover for storm drainagepipes shall at a minimum comply with the requirements of the VirginiaDepartment of Transportation Design Manual. .- - - Formatted: List Paragraph, No bullets or numbering 7.2.10 Structural Design All inlet structures, frames and grates; and pipes shall be designed to withstand a HS -20 loading, unless a pipe crosses a railroad, in which case the pipe shall be designed for railroad loads. The structural design shall consider the depth of cover, trench width and condition, bedding type, backfill material, and compaction. 7.3 Installation All inlets, pipes, and associated structures shall be installed in accordance with VDOT - - Formatted: Indent: First line: 0" Specifications and the manufacturer's recommendations. The characteristics of the trench, bedding, and pipe material all impact the structural strength of the pipe system. The installed pipe conditions shall comply with the design assumptions and calculations. HDPE pipe installation shall comply with the County of Roanoke Inspection Specifications for HDPE Pipe. A copy of this document is included in Appendix 7B. Storm drains shall not be installed through contaminated soils or groundwater 7.3.1 Bedding Material Bedding material and installation shall comply with the requirements of the VDOT Specifications. Use Class I backfill (crusher run and #21) to one foot over the pipe for HDPE, up to the spring line for RCP. #57 stone is not allowed as pipe bedding_ 7.3.2 Backfill Backfill shall be suitable material and shall be placed and compacted in accordance with the VDOT Specifications (PB -1 detail). Use Class I backfill (crusher run) to one foot over the pipe for HDPE, and up to the spring line for RCP. — - - Formatted: Indent: First line: 0" - - Formatted: Indent: Left: 0.5", First line: 0" A minimum of 12" cover shall be placed over the top of a storm drain pipe prior - - Formatted: Indent: Left: r', First line: 0" to placement of pavement or other surface treatment. Additional minimum depth of cover shall be provided if recommended by the manufacturer. COUNTY OF ROANOKE q444x/1/16 7-13 STORM DRAINS STORM DRAINS CHAPTER 7 All pipe installed must be inspected and approved by the County's .- - - Formatted: Indent: Left: r', No bullets or numbering, Tab Inspector prior to any backfill being placed. The Contractor must provide 24 hour stops: 0.5", Left notice to County prior to installing backfill so that County staff can be present for inspections. 7.3.3 Separation of Utilities Where storm drains cross other utilities, at least 1 -foot of vertical separation shall be provided. Where 1 -foot of vertical separation cannot be provided, special provisions shall be made in the bedding and backfill to avoid settlement that could cause point loadings on the storm drain or other utility. Water lines shall not pass through a storm drain inlet or manhole. 7.4 Environmental Impacts Construction or modifications to storm drains shall comply with all applicable - - Formatted: Indent: Left: r', First line: 0" laws and regulations. The applicant is responsible for procuring all necessary permits. 7.5 Erosion Protection at Outfalls Erosion protection at storm drain outlets shall be provided in accordance with the - - Formatted: Indent: Left: 1", First line: 0", Tab stops: Not outlet protection standards contained in the VA E&SC Handbook and the VDOT at 0.5" Drainage Manual. 7.6 Maintenance Requirements The permittee is responsible for maintenance of storm drains until construction is - - Formatted: Indent: Left: r', First line: 0", Tab stops: 1", complete, including final clean up and site stabilization, to the satisfaction of the Left + Not at 0.5" County. n f4ei4ha eampletimq ,. f eR4g.,.,...,..:,.r the , pe ft , .,:t t NO R440 nb.nit M,.,tay :rt,.... , ,..t,,.,..,.,..,,,..., PO fftf r,,,.. - - Formatted: Indent: Left: 1", First line: 0"Tab stops: 1", �S 6rro",�roz,S l ,W-RO =S9�i6�,i-emEw -44- "ansa Left + Not at 0.5" COUNTY OF ROANOKE q4144X11116 7-14 STORM DRAINS STORM DRAINS APPENDIX 7A AIDS FOR STORM DRAIN SYSTEM DESIGN FROM CHAPTER 9, VDOT DRAINAGE MANUAL APPENDIX 7A Table 9-1, Criteria for Inlet Design Table 9-2, Design Frequencies for Storm Drain Conduit Notes that accompany Table 9-1 and Table 9-2 Figure 9-10, Losses in Junction due to Change in Direction of Flow Lateral Appendix 913-1, LD 204 Stormwater Inlet Computations Appendix 913-2, LD 229 Storm Drain Design Computations Appendix 913-3, LD 347 Hydraulic Grade Line Computations Appendix 9C-1, Flow in Triangular Gutter Sections Appendix 9C-3, Flow Characteristic Curves (24" Gutter)- VDOT Standard Appendix 9C-23, Manning's Solution for Flow in Storm Drains Appendix 9C-24, Nomograph for Computing Required Size of Circular Drain for Full Flow Appendix 9C-25, Concrete Pipe Flow Nomograph COUNTY OF ROANOKE q444x/1/16 7A-1 STORM DRAINS STORM DRAINS APPENDIX 7A CRITERIA FOR INLET DESIGN DESIGN FREQUENCIES FOR STORM DRAIN CONDUIT Roadway Classification Design Speed Design Storm Maximum Design Roadway (mph) Spread Width P Frequency Intensity Classification With or Without Shoulder I All 1 10 (year',) (in/hour) (ft) Principal Arterial <50 10 Actual Sh. Width +3 On Grade>50 10 Actual Sh. Width Sag All 10 Actual Sh. Width +3 Locations On Grade <50 N/A° 4 h Driving Lane + Gutter Width (If Any) On Grades >50 10 Actual h Driving Lane + Gutter Width (If Any) <50 N/A° 4 /2 Driving Lane + Gutter S Sag — Width (If Any) Locations >50 50 Actual h Driving Lane + Gutter Width (If Any) Minor Arterial, Collector, Local On Grade _<50 N/A° 4 Sh. Width +3 >50 N/A° 4 Sh. Width Sag N/A^ 4 Sh. Width +3 Location All On Grade All N/A° 4 h Driving Lane + Gutter o Width (If Any) y Sag N/A^ 4 /2 Driving Lane + Gutter g Location All Width (If Any) DESIGN FREQUENCIES FOR STORM DRAIN CONDUIT Roadway Classification Design Speed (mph) Design Storm Frequency (year ) Principal Arterial With Shoulder All 25 Without Shoulder _<50 10>50 25 Minor Arterial, Collector, Local With or Without Shoulder I All 1 10 COUNTY OF ROANOKE q444x/1/16 7A-2 STORM DRAINS STORM DRAINS APPENDIX 7A NOTES - CRITERIA FOR INLET DESIGN AND DESIGN FREQUENCIES FOR STORM DRAIN CONDUIT Notes I through 3 are General Notes and should be applied to any functional classification roadway where the site conditions are comparable to the conditions described in each note. ' At locations where the vertical alignment of the roadway creates a sag condition in either a depressed roadway section or a roadway section utilizing concrete barriers, and ponded water on the roadway can only be removed through the storm drain system, a 50 -year storm frequency and the actual time of concentration should be used as the design criteria for both the drop inlet and the pipe system. 2 Federal Flood Insurance criteria dictate that the effects of the 100 -year storm event (using the actual time of concentration) on buildings insured under the Flood Insurance Program must be investigated. Such cases should only be encountered where the roadway traverses a designated floodplain area containing insured buildings and the depth of water on the pavement is sufficient to overtop the curb and flow to the buildings. 3 The maximum design spread width may not be obtainable due to the pavement/shoulder slope and the height of the curb. In locations where the curb would be overtopped and water would escape the roadway section prior to achieving the maximum design spread with, the maximum depth of ponded water allowed adjacent to the curb for the design storm shall be curb height minus one (1) inch. Notes 4 through 5 should normally be applied to the specific locations as noted in the criteria table. 4 At location where it may be reasonably anticipated that the runoff from storm events with rainfall intensities greater than 4 inches per hour will overtax the drop inlet system to the point that excess flow will escape the roadway section and result in potential damage to the adjacent property and/or roadway right of way, the drop inlet system shall be analyzed for a check storm event with a rainfall intensity of 6.5 inches per hour. If all of the runoff from the check storm event is found to be contained within the roadway section, both at the site and down grade, or if runoff escaping the roadway section is found to not be damaging to adjacent property, the drop inlet system may be used as originally designed under the general criteria. If the drop inlet system fails to meet the check storm criteria, it must be re -designed to accommodate the runoff from the check storm event. 5 Drop inlets in these locations are prone to clogging and are often located in areas where maintenance is difficult. To compensate for partial clogging, the computed slot length value should be adjusted by multiplying by a factor of two (2). The adjusted computed slot length value should then be used to determine the slot length specified on the plans. COUNTY OF ROANOKE q444x/1/16 7A-3 STORM DRAINS STORM DRAINS APPENDIX 7A LOSSES IN JUNCTION DUE TO CHANGE IN DIRECTION OF FLOW LATERAL V,2 HL= K V, = Valadty of flow in lateral in f.p.s. Acceleration due to gravity, 92 ft(seclsec Feet of tread IQsi in Jct. due, to change in direotlo of lateral flow Factor Imm graph 80 I I l 1 7 I1 0 0 0.1 0.2 0.3 0.+4 0.5 0.6 07 Fa1.11..17 K COUNTY OFROANOKE q4/ X/1/16 7A-4 STORM DRAINS STORM DRAINS APPENDIX 7A STORMWATER INLET COMPUTATIONS (VDOT LD -204) COUNTY OFROANOKE q444XI1/16 7A-5 STORM DRAINS 1111fl�lioi COUNTY OFROANOKE q444XI1/16 7A-5 STORM DRAINS STORM DRAINS APPENDIX 7A STORM DRAIN DESIGN COMPUTATIONS (VDOT LD -229) N N COUNTY OFROANOKE q444XI1/16 7A-6 STORM DRAINS STORM DRAINS APPENDIX 7A HYDRAULIC GRADE LINE COMPUTATIONS (VDOT LD -347) rrW N �a m G y a 2 N Z N � � N y r CT v IS M v It O N tum wm �j z o ri d I1 N � b (9 N N 23 O O a h II IP A Y Y Y Y r m vD flo o d c a I YI Ll X Y Y Y � s r COUNTY OFROANOKE q444XI1/16 7A-7 STORM DRAINS STORM DRAINS APPENDIX 7A FLOW IN TRIANGULAR GUTTER SECTIONS COUNTY OF ROANOKE ;/444x/1/16 7A-8 STORM DRAINS =.37 S 05 Tz,er - --- 5+ EXAMPLZ: GIVEN' _ fb=QQI 0:03 [i 5=a04 ; T =6 FT i?.8 0.2 FI W)' 0-6--40 fj a 2 4 rT 315 CM,0.036 FT -S 4.4 l].l 00'0 z 20 T (FT) 0.05 .G4 x 30 t]$ to x oxe14�� 000 ,1 icy cow E 0,04 rEXO04 - t}t38 4 4,GF 0.002 O, i I D:8 0.001 OOJ G _ T 0oat lj F-DrV-Shape, use the nomograph with CLOCK 0.4 r x2 r = Sxr Sxzl(&T * Bx2) a.a�►a T 2} To dBlermine discharge in gutter with v. w � � 76 torr,pasit areas aiopes, find Q$ swing T, and $,- Then„ un App. 9C•B to p find Eo. Ti total digrhNp Is x Q::Q jl-E,L and QivwG-%, COUNTY OF ROANOKE ;/444x/1/16 7A-8 STORM DRAINS STORM DRAINS APPENDIX 7A FLOW CHARACTERISTIC CURVES (24" GUTTER) rw,x.r4 -rd, rw FiO1J tidiAP4C EEi3TIC CT✓PVf-- srwr,r,.r rxw xax� re.�ea a rai s�xae -lwsr COUNTY OF ROANOKE ;/444x/1/16 7A-9 STORM DRAINS STORM DRAINS APPENDIX 7A MANNING'S SOLUTION FOR FLOW IN STORM DRAINS 2400 0.5 0.4 2490 599 0, g 4.2 10017 Q.7 e06 c 0.1 4w o 0A 0.0$ tC}Q � 0.06 400 240 1.4 0.04 .340 200 MD w 0.02 00 18p 0r— x.908 0 % flE u t ao 84 72 # Oe 0. O6 M- Y 0.004 4i1i 44 W J 40 W a 54 0. Q3 > 0- 00Y 30 64 yo- 48 42 O. fl 2 40/ 20 �, U 36 „ x 3 0.001 m = 30 0-0 10 0, arae 0. 000ra 10 ; 24 2! 0.006 4 -- 0. 0044 2 1- - 8 5 cc o 1 S 1 0.402 = r W 4� 0.0002 a cc 12 x 10 a 0- 90G 1 y o'' B 7 D 2 y , y 0.00006 0.00004 9 I. a 4 10 Q$ 0-000oz Q6 4. S a 00001 A. A 0.3I S 0.0047006 [4.0 0"Q 4 COUNTY OF ROANOKE q444x/1/16 7A-10 STORMDRAINS STORM DRAINS APPENDIX 7A NOMOGRAPH FOR COMPUTING REQUIRED SIZE OF CIRCULAR DRAIN FOR FULL FLOW 1604 4tt0 looEx_�:- +"irirr dr'sehcs+ga Q-,.� C. f;5. DOD frrcfiQ,�r {c+car rr. C7.pI5 500slope of 0.0060"p&,- font Find d►vmpecf- lSrrrChe3 cr;e `GO velocify of 3..5 filper- second. 380 6.y I0!lesufn crashed /rrre. a COUNTY OF ROANOKE q444x/1/16 7A-11 STORMDRAINS Za4 .6041 2 .Goal G 120 14@ .0002 90 .0*03 'DOCZ 100 54 as .aGGa .8006 Ir} va C9 ,h 72 W 66 .0Do* Cana 3 It ea pa x Se o .DOGS uaa6 a no 2 .ante 54 _80416 r 44A014 1 4LLJ •a Z 42 .0424 r z 31r p sa •r+43a•oaea 16 0� Z SO 33 ,4040 8410 y F.r 50 -00404. W ,D064 Q t4 27 C3 R .0949 ,0864 ( 241 Q 41 4 4] J'< ,aa6O IL A244 WIN 3 10 L61 i3 .0300 4200 e 9 % .404 4300 6 7 � � 12 - .0400 .4l OG 9 d /Y x0600 0640 10 S IG 1000 ,Qa DO 11 .14 44 13 a 6 IA IS a COUNTY OF ROANOKE q444x/1/16 7A-11 STORMDRAINS STORM DRAINS CONCRETE PIPE FLOW NOMOGRAPH iWO Soo 0001 saa -100 600 .000z w0 -aaa3 400 APPENDIX 7A 'L5 96 = Aw[ 9{] A 01 h -�[ SS 1 72 „ V ZL 44 60 }- F 6 SOC /f ! y �s•I AOS 304 Ica a.I 49 .00-1 LL' ` 1,5 so 130 W 144b LL. 70 ell- 3% CD 1 J i3 EL 24+x;9 3fl � 30 .. 3-000 Lai Lai 4D 40010 27 ,dz S 0" - 24 <` 8 gp acoo 50 0 2i J93 rix 81N u�- Y arvEiv: o a 2: arst L= #50; p = 27" CD ,Qt 4 ipe. Reod Y=5-$ fax arld Lsi50, AeCord .0 t,C s L4 ,j n. i IE >r .OS C7 4Q aE 20 — !3 '09 1 ,SO 12 APPENDIX 7A 'L5 COUNTY OFROANOKE ;444Y/1/16 7A-12 STORM DRAINS -�[ SS 1 4 ti ZL zaa }- F 6 SOC .7 1 G 9 304 _� itF = 600 2 ,0 -a ` 1,5 W 144b r� L2 [u CD 1 J i3 EL 24+x;9 s 1 # � 3 i is 3-000 Lai Lai �4 40010 I` S 0" 1 5 4Q0# <` 8 gp acoo 7 iAooa a rix 81N u�- Y arvEiv: o a 2: arst L= #50; p = 27" Y5 SOLUTION -L Troes*d lr4Fn !h. lelf, rtad ia-Zl Cli and D=27,r R6Cbft S1=AQ5 "&d Y • S.3 ipe. Reod Y=5-$ fax arld Lsi50, AeCord .0 t,C s L4 ,j n. SD 1$ COUNTY OFROANOKE ;444Y/1/16 7A-12 STORM DRAINS STORM DRAINS APPENDIX 7B APPENDIX 7B INSTALLATION PROCEDURES FROM ROANOKE COUNTY Inspection Specifications Iifor HDPE PIPE COUNTY OF ROANOKE q444XI1/16 7B-1 STORM DRAINS STORM DRAINS INSPECTION SPECUICATIONS FOR. HDPE PIPE TABLE OF CONTENTS I. Overview II. Pre -Installation a. Trench Widths b. Dewatering III. Embedment a. Definitions b. Foundation c. Bedding d. Haunching e. Initial Backfill f. Final Backfill IV. Joints V. Typical Details APPENDIX 711 COUNTY OF ROANOKE q444XI1/16 7B-2 STORM DRAINS STORM DRAINS I_ OVERVIEW APPENDIX 7B The County of Roanoke, in conjunction with the Virginia Department of Transportation, is allowing HDPE pipe for storm sewers. HDPE pipe may be used for any size up to 48" in diameter. Anything above that must use previously approved pipe material. 11. PRE-INSTALII ATION A. Trench "Widths Trench widths used in installing HDPE pipe have been established in AASHTO Section 30 and ASTM D2321. Table 1 provides the recommended trench widths for most installations to provide the proper placement and compaction of backfill material in the haunches around the pipe. Trenching should be completed in the existing soils with sidewalls reasonably vertical to the trip of the pipe. When excavation depths or soil conditions require shoring or use of a trench box, the bottom of the shoring or trench box should be placed no lower than the top of the pipe. This prevents disruption of the backfill when shoring of trench box is removed. If this practice cannot be followed, considerations should be given to leaving the shoring in place. Refer to Table 1. TABLE i -SUGGESTED MINIMUM TRE14CH WIDTHS Nominal Pipe Diameter, (in) Pipe QD in Minimum Trench Width (in) 4 4.78 21 5 5.92 23 8 9.11 25 1a 11.36 28 12 14.45 31 15 17.57 34 18 21.2 38 24 27.8 48 3© 35.1 66 36 41.7 78 42 47.7 83 48 52.7 j 88 COUNTY OF ROANOKE q444XI1/16 7B-3 STORM DRAINS STORM DRAINS B. Dewatering APPENDIX 7B HDPE pipe will float in standing water. Therefore, it is imperative that the trench be dry when installing the pipe. Sump pumps, well points, or other methods may be needed to insure a dry trench. Ill[. EMBEDMENT Embedment materials are those used for the foumdation, bedding, haunching, and initial backfill. An illustration of this can be found in Figure I page 5. A. Definitions I . Class I — Angular crushed stone or rock (No. 25 or 26 stone). 2. Class. 11— Clean, course grained materials, such as gravel, course sands, and gravel/sand mixtures. 3. Class 111— Course grained materials with fines including silty or clayey gravels or sands. Gravel or sand must comprise more than 50% of Class III materials. 4. Class N and. V materials are not recormnended for embedment materials. B. Foundation A stable foundation must be provided in order to insure proper installation. Unsuitable or unstable foundations maybe replaced with a suitable bedding material, placed in 5" lifts. COUNTY OF ROANOKE q4114XI1/16 713-4 STORM DRAINS STORM DRAINS C. Bedding APPENDIX 713 4 The middle of the bedding, equal to 113 of the pipe outside diameter, should be loosely placed. The remaining stone for the bedding should be compacted to a minimum 90% standard proctor density. Class i stone will be acceptable material for use, except when the f6tindation is in soft, yielding, or otherwise unsuitable material.. Then, the bedding material shall be #57 stone for the specified depth, and then capped with. 4" of Class I stone. D. Haunching Haunching provides the pipe with its main support and strength. Extra care must be taken in installing the haunching. The haunching will extend from the bottom of the pipe up to the spring line. For larger diameter pipes (30"- 48"), embedment materials should be worked in by hand. Class I stone may be used and compacted in 8" maximum lifts, compacted to 90% standard proctor density. E. Initial Backfill Initial Backfill will extend from the spring line to 12" above the top of the pipe. The backfill material shall consist of Class I stone, compacted in 6" lifts, compacted to 90% standard proctor density. F. Final Backfill Final back fill should be the same material as the proposed embankment. Generally, the excavated material will be used for the final backfill. The final baelcEll is to he placed in 12" niaxinmrn lifts, compacted to a minimum 85% standard proctor compaction. COUNTY OF ROANOKE q444XI1/16 713-5 STORM DRAINS STORM DRAINS igarm Trench Cross Sector Excavated Tra;ich VV!dth � � Bacicil3l ` � Initial N Backfill SpringMa--- La -a �' _ r • a. Q. Haunting -� Bedding Foundation APPENDIX 7B 5 7Z" Rpe Lent Haunch Zone COUNTY OF ROANOKE q444x/1/16 713-6 STORM DRAINS STORM DRAINS APPENDIX 7B IV. JOINTS For watertight joints, an ASTM F-477 elastomeric rubber gasket shall be used at all joints of pipe. To install this gasket, the ends of the two pipes being connected shall be cleaned. The gasket shall be applied onto the bell with the marking facing the coupler. Apply lubricant liberally to both joints of the pipes. Align the pipe to push it together on grade. Generally, pipe should be laid from the downstream end and working upstream. 'Small diameter pies (>24") can be pushed together by hand. Larger diameter pipes may need to use a bar or equipment to push the pipe together. if that is used, a wood block should be used to prevent any damage to the bell of the pipe. Special care should be taken to ensure that no bedding material gets into the joints. Stone or any other material that gets into the joint may cause leaks_ Rubber gaskets are normally installed at the factory. However, if a pipe needs to be cut in the field, the gasket shall be stretched over the bell prior to connecting pipes together. COUNTY OF ROANOKE q444XI1/16 7B-7 STORM DRAINS STORM DRAINS TYPICAL DETAILS AND VDOT TABLES AND DETAILS APPENDIX 713 COUNTY OF ROANOKE q444XI1/16 713-8 STORM DRAINS STORM DRAINS F, !2xl',f APPENDIX 7B w COUNTY OFROANOKE q444x/1/16 713-9 STORM DRAINS STORM DRAINS APPENDIX 7B COUNTY OFROANOKE q444XI1/16 713-10 STORM DRAINS STORM DRAINS APPENDIX 7B ° a S+ 04 _ C E M a - EPvE Qw NAM �azd°�d�okdc a �EzYq g H c p'-.Lg �fR�Vgw�¢w� MAP eCK pO a® ZZ Gv`i ,.w e Z Il� gi $ ���ig � ?�LL ya iiia ' gq1 W� ��,�00 N� G- oammo.am �3�Na �a Sri Ew a e Ea a �g c -001 maim 0 IftlRoll iY COUNTY OFROANOKE q444XI1/16 713-11 STORM DRAINS STORM DRAINS H Q• C W w 7 �$ 3j "a vy C gs ow - Lu ig L spa ra_ qW._ uj w p V y r it _ 12 t e G oat � 5 W V $rp Ya APPENDIX 7B 3j "a C gs ow - $m Sn,x L spa qW._ w p V y r it _ 12 t e G oat � 5 I= J ux $rp Ya x c - ui w a r -Ln m 3 x p w APPENDIX 7B J W 1 > a- ::. tJ p � � z Q � i iL Q In u- E W J i m 3 J �-7 L.7 D:: C:)LJ J ¢ L 60-1 c, t > Z) x COUNTY COUNTY OFROANOKE q444XI1/16 713-12 STORM DRAINS C gs ow - $m Sn,x L spa qW._ w p V y t e G oat � 5 I= J $rp Ya J W 1 > a- ::. tJ p � � z Q � i iL Q In u- E W J i m 3 J �-7 L.7 D:: C:)LJ J ¢ L 60-1 c, t > Z) x COUNTY COUNTY OFROANOKE q444XI1/16 713-12 STORM DRAINS STORM DRAINS APPENDIX 7B COUNTY OF ROANOKE q444XI1/16 7B-13 STORM DRAINS t J t r rl d +d x� l M X^ _ E i. t7Z $ �� zNa W u; MAA 1p, � g \ZiY O I°1=UF- rN cFi Uo a HWr� H U Y I�rEA^.i lel zadf. Lr! k`I!JR o g 0 111 tfz:. [111 11EIINI ILa i ®�� 0 C3 W d J zoys v ��a m Z i'o`i UB :;P is $ 7 viii r bg 4 1i u. Le1 O x u �a 7 W uJ al' U La s i o sd v Z 1 Lel Lei lm a w ul 1, O a=mn � '$ � ye LL[ V V1I 0 to /Lys9 OICL. 0 rt g� a� j Q Z a,r� '^ U) m i Wi r ,w U3 b � ilillfjj ?xJXF�� '7y$uf pv� COUNTY OF ROANOKE q444XI1/16 7B-13 STORM DRAINS RESIDENTIAL LOT DRAINAGE CHAPTER 8 Chapter 8 - Residential Lot Drainage (RESERALED) Residential lot drainage�or residential lots that are part of a common plan of development , - Formatted: Highlight includes providing drainage and/or grading of the land to direct surface drainage away from building and toward streets, drainage conveyance structures, BMWs, or sheet flow. 8.1 References Except where more stringent requirements are presented in this Design Manual, lot drainage shall comply with state requirements. The primary design references are: • VDOT Drainage Manual • VA SWM Handbook • VA ESC Handbook • BMP Clearinghouse • State Building Code 8.2 General Lot Grading Lotrg ading plans establish therg ading relationships between adjacent properties, determine the drainage areas and sizing of stormwater conveyance systems and BMPs, and account for the build out of the developed lot. 8.3 Construction Plan Requirements Individual lot grading and drainage shall be shown on the site plans and shall include the following information: • All high or low points shall be labeled on the plans. • All impervious areas shall be shown on the site plans. Additionally, all impervious areas shall be shown on the plot plans and shall not exceed the impervious areas shown on the approved site plans. Building pads sizes shall be noted on the site plans and the plot plans. If plot plans show an increase in the impervious areas then additional stormwater BMPs and a redesigned site plan may be required. Designers are encouraged to provide an adequate building pad on the site plans in order to meet homebuilders desired pad size and prevent redesign of the plans. COUNTY OF ROANOKE 7144X/1/16 8-1 RESIDENTIAL LOT DRAINAGE RESIDENTIAL LOT DRAINAGE CHAPTER 8 • Proposed and existing contours at two foot intervals. The proposed contours on Plot plans shall conform with the intent of the approved site plan". - - Formatted: Font: Not Bold •-----�-----------------------------------= Formatted: Font: Not Bold • All stormwater conveyance structures (drainage pipes, swales, etc.) shall be shown on the plans. - - Formatted: Font: Not Bold • All BMPs and swales shall be shown on the plans. • A finished floor elevation (FFE) shall be provided for each building pad on the site plan to the nearest foot. The plot plan shall show a FFE that is; onsistent with_- - - Formatted: Highlight the intent of the approved site plan. See Section 12.2 for lots that are located in a floodplain. • Roof drains shall be shown on plot plans and shall meet the drainage areas as shown on the approved site plan. Rooftop disconnects used for stormwater quality shall be shown on the site plan. • Plot plans shall show that grading is; onsistent with the approved site plan. If plot , - Formatted: Highlight plansts not consistent with the approved site plan then additional stormwater - - Formatted: Highlight structures and a redesigned plan may be required. • residential lots that are not part of a common plan of development may require - Formatted: Highlight residentialllot _ grading at the discretion of Roanoke County due to the need of _ _ _ - - - Formatted: Highlight SWM plans, drainage issues, or other circumstances= - - - - - - - - - - - - - - - - - - - - Formatted: Highlight • Residential driveways shall meet VDOT specifications for driveways abutting public roadway and Roanoke County's Street standards for driveways abutting a private roadway for maximum driveway grades. COUNTY OF ROANOKE 7444X/1/16 8-2 RESIDENTIAL LOT DRAINAGE STORMWATER DETENTION Chapter 9 — Stormwater Detention CHAPTER 9 Stormwater detention facilities are a means of attenuating increases in peak flows caused by land development. In addition to providing flood control, stormwater detention facilities can protect downstream channels from increases in erosion ara ide a w was„ e ,.F,.,,.*Rr gida4. *re&r**. This chapter addresses general requirements for detention facilities as they relate to attenuating peak flows. mss - When a storm event occurs, stormwater runoff enters the detention facility. The outlet structure allows a portion of the stormwater runoff to discharge from the facility and the remainder of the stormwater runoff is temporarily stored. After the end of the storm, water continues to discharge from the facility until it is empty. Stormwater detention facilities include: • Detention Basin • Retention Basin • Extended Detention Basin • Enhanced Extended Detention Basin • Underground Detention A detention basin is a pond that is normally dry. When a storm event occurs, it temporarily stores stormwater runoff, discharging it at a controlled rate through a hydraulic outlet structure to a downstream conveyance system. A retention basin is a stormwater pond which includes a permanent pool, even during non - rainfall periods. The pond includes storage above the normal pool elevation which temporarily stores stormwater runoff during storm events. An extended detention basin is a pond which temporarily stores runoff for a specific time period following a storm event, discharging it at a controlled rate through a hydraulic outlet structure to a downstream conveyance system. An extended detention basin is dry during non -rainfall periods. An extended detention basin provides more protection to the downstream channel from increases in erosion than a detention basin by releasing stored runoff at a lower rate over a longer time period. A typical plan and profile for an extended detention basin are detailed in the VA MP Clearinghouse. An enhanced extended detention basin is similar to an extended detention basin, but it also incorporates a shallow marsh in its bottom to : ae ,.4dit: ona alis , 40A*m04* ,.,.:,.,. ,,:............. :r C,.,.. tff 11. An underground detention facility consists of pipes or manufactured underground chambers used to temporarily store stormwater runoff following a storm event, discharging it at a controlled rate COUNTY OF ROANOKE x/1/16 9-1 STORMWATER DETENTION STORMWATER DETENTION CHAPTER 9 through a hydraulic outlet structure to a downstream conveyance system. An underground detention facility is dry during non -rainfall periods. In addition to detention and retention basins, the design requirements specified by this chapter and the VA BMP Clearinghouse shall apply to ponds created as private property amenity features.afta�. 9.1 References Except where more stringent requirements are presented in this Manual, the design and construction of stormwater detention facilities shall comply with VDOT and DCR VA BMP Clearinghouse requirements. The primary design references are: • VA SWM Handbook • VDOT Drainage Manual • VA E&SC Handbook • VDOT Standards • VA BMP Clearinghouse 9.2 Design Methodology and Criteria 9.2.1 Hydrology See Chapter 4 for methodology used to determine design flows. 9.2.2 Design Flows and Storage Volumes To properly design stormwater detention facilities, a flow routing program shall be used with an appropriate elevation — discharge - storage relationship for the design storm events. 9.2.3 Minimum Contributing Drainage Area A stormwater retention basin, which contains a permanent pool, requires at least 10 acres of watershed drainage and/or a good source of base flow to maintain the permanent pool. A minimum drainage area of 20 acres shall be used when the basin is located in an area of high visibility to prevent unsightly drying of the permanent pool. Retention basins are best suited for regional and large drainage area projects. COUNTY OF ROANOKE x/1/16 9-2 STORMWATER DETENTION STORMWATER DETENTION 9.2.4 Detention Facility Locations CHAPTER 9 Stormwater detention facilities should not be constructed within a Federal Emergency Management Agency (FEMA) designated 100 -year floodplain. If this is unavoidable, the facility shall comply with all applicable regulations under the National Flood Insurance Program, 44 CFR Part 59._ The following factors shall be addressed when siting a stormwater detention facility: • Geotechnical conditions including soil conditions; • Groundwater levels and it's potential impacts; • Karst topography; • Existing and proposed utilities; • Aesthetics on surrounding properties; and • Environmental impacts including wetlands. Stormwater basins shall be located to minimize the aesthetic impacts to the surrounding property. Basins shall be set back from property lines a distance equal to the minimum width of the applicable required buffer yard. Locate stormwater detention facilities to avoid collecting significant amounts of drainage from offsite areas. Stormwater basins shall be set back at least fifty feet from a residential dwelling structure as measured from the wall of the structure to the top of the basin embankment. In proposed single family residential subdivisions, the stormwater management facility shall be located in a single non-developed lot. 9.2.5 Basin Grading Stormwater basins shall be graded to blend into the surrounding topography with the following conditions: • Basin side slopes shall be no greater than 3:1. • Provisions shall be made for the long-term maintenance of basin slopes and periodic access for maintenance of the outlet structure, emergency spillway, and removal of accumulated sediments. COUNTY OF ROANOKE x/1/16 9-3 STORMWATER DETENTION STORMWATER DETENTION CHAPTER 9 • The maximum allowable depth of a stormwater detention basin shall be 15 feet, as measured from the top of the embankment to the lowest point in a basin. • The bottom of the basin shall have a low flow or pilot channel to facilitate complete drainage. The pilot channel shall convey flows from a 2 year storm event and prevent standing water during dry -weather conditions. The pilot channel shall be sloped a minimum of 2% if it is a grass -lined channel and at a minimum of 1% if concrete -lined. In addition to the above requirements, the follow standards of practice should be used when designing a stormwater basin to the extent possible: • The length -to -width ratio of a stormwater basin should be a minimum of 2:1. A 3:1 ratio is desired where possible. This prevents short-circuiting of the basin's storage areas. • To minimize cut and fill, the long dimension of a stormwater basin should run parallel to the contours. 9.2.6 Embankments and Emergency Spillways Stormwater basin earthen embankments shall be designed and constructed to maintain structural integrity during the 100 -year frequency storm event. When applicable, Virginia Dam Safety regulations shall apply. The minimum top width of an embankment shall be 10 feet. Width may be greater based on the overall height. Embankment side slopes shall be no steeper than 3:1. Embankments with an emergency spillway must provide at least one foot of freeboard from the maximum 100 year storm water surface elevation to the top of the embankment. An embankment without an emergency spillway must provide at least two feet of freeboard from the maximum 100 year storm water surface elevation to the top of the embankment. A geotechnical study shall be required for all stormwater basins with constructed embankments greater than 6 feet in height as measured from the base of the embankment. Cee �h" ._ 13 Ira.. _, Epti_ew. i4s of a g,.,..,.,.," e �. The commented [AG1]: geotechnical study shall be performed by a licensed geotechnical engineer or licensed geologist and the report submitted to the County. COUNTY OF ROANOKE x/1/16 9-4 STORMWATER DETENTION STORMWATER DETENTION CHAPTER 9 9.2.7 Outlet Structures and Release Rates Stormwater Release Rates - Formatted: Font: Bold Stormwater detention facilities shall be designed with an outlet structure to control the release rate from stormwater being held in the facility. Design release rates shall meet the requirements set forth in Chapter 4, except that extended detention facilities shall be designed based on releasing the design storm runoff volume in a prescribed time as indicated in the VA MP Clearinghouse. All stormwater detention facilities shall be empty within 72 hours following the storm event. Ponds created as private property amenity features, not being used as stormwater management, shall be exempt from release rate requirements. J._ Outlet Structure Criteria - Formatted: Font: Bold Outlet structures generally include a principal spillway or outlet and an emergency overflow. An outlet structure may take the form of a drop inlet, pipe, weir, or orifice. The principal spillway or outlet is intended to release flow from the design storm events at the necessary controlled rate, without allowing flow to enter the emergency spillway or overflow. The sizing of the outlet structure shall be based on the results of the hydrologic routing calculations or model. —Pile *H the *e4gdetiey E4 el,.ggit , *'+e Outlets from stormwater detention facilities shall be designed to function without manual, electrical, or mechanical controls. Where necessary, energy dissipaters shall be placed at the outfall to provide a non-erosive velocity from the facility to a channel. See Chapter 10 for the design of outfall protection. Where a stormwater basin with an earthen embankment does not have an emergency spillway, the principal outlet or spillway shall be sized to safely pass the flow from the 100 -year frequency storm without over topping the earthen embankment. In this instance, the design of the primary outlet structure shall include a 50% clogging factor duringtie 100 -year frequency storm as a safety factor. When the primary spillway is less than 24 inches wide. it shall be considered inoperative during a 100 - ear frequency storm COUNTY OF ROANOKE x/1/16 9-5 STORMWATER DETENTION STORMWATER DETENTION CHAPTER 9 Where a stormwater basin with an earthen embankment has an emergency spillway included, two conditions must be evaluated. The routed 100 -year WSEL must provide one foot of freeboard between the 100 -yr WSEL and the top of the berm. Secondly, the spillway must be evaluated to show that the 100 -year flow passes through the spillway without overtopping the berm. Both conditions must be evaluated and met. The ability to pass the 100 -year now through the spillway is typically evaluated by routing the flow through the spillway only with all other outlets ignored or by simply evaluating the 100 -year flow through the dimensional equivalent weir using F1owMaster, similar software, or applicable weir equations. Where a stormwater basin with an earthen embankment does not have an emergency spillway included, two conditions must be evaluated. The routed 100 -year WSEL must provide two feet of freeboard between the 100 -year WSEL and the top of the berm. Secondly, the principal outlet or spillway (riser weir or culvert outlet) shall be sized to safely pass the 100 - year frequency storm without overtopping the beim. For this condition, the evaluation shall include a 50% clogging factor and is typically evaluated assuming a weir length (perimeter) or culvert (diameter) based on dimensions providing 50% of the design flow area. The principal spillway must be a minimum of 24 inches wide/diameter unless calculations show that the freeboard requirements and no overtopping conditions are met. For examples of design calculations of outlet structure orifices and weirs, see the VDOT Drainage Manual and VA MP Clearinghouse. All riser structures shall be cast -in-place or precast concrete, unless a substitute material has been approved by the County. VDOT standards for riser structures may be found in the VDOT Standards. Outlet pipes shall be reinforced concrete pipe with rubber gasket watertight joints, shall have appropriate seepage control, and shall be installed on a concrete cradle from the tie of the pipe to the riser for the entire length of the outfall pipe. Concrete cradle shall be in accordance with the requirements of the VDOT Standards. C. Adequate Channel Formatted: Font: Bold Outflows from stormwater detention facilities shall be discharged to an - - Formatted: indent: Left: 1.5', First line: o" adequate channel. For adequate channel requirements, see Chapter 5. 9.2.8WateF QualityOML__ COUNTY OF ROANOKE x/1/16 9-6 STORMWATER DETENTION STORMWATER DETENTION 9.2.9 Landscaping CHAPTER 9 Stormwater basin embankments shall be vegetated. Selection and plant installation shall be in accordance with the standards of the VA SAIN 9*R44ee4BMP Clearinghouse. Trees and shrubs shall not be planted within a stormwater detention basin, nor on a stormwater basin berm, dam, or emergency spillway. The VA MP Clearinghouse shall be utilized for guidance for landscaping in the marsh areas of enhanced extended detention basins. Native plants will be used to the maximum extent possible. 9.2.10 Underground Detention �. -- Materials-------------------------------------- Formatted: Font: Bold All materials used in underground detention facilities shall be corrosion resistant consisting of reinforced concrete, aluminized corrugated metal pipe, corrugated high density polyethylene pipe, or similar approved material. J.___ Slope------------------------------------------ Formatted: Font: Bold Underground detention facilities shall be sloped to drain at a minimum floor slope of 4--05 percent. ,C-- - - Capacity Formatted: Font: Bold Underground detention facilities shall be sized such that the 100 -year design storm may be routed through the facility with no damage to the surface property. D. Accessibility and Maintainability ...... - - - I Formatted: Font: Bold COUNTY OF ROANOKE x/1/16 9-7 STORMWATER DETENTION STORMWATER DETENTION CHAPTER 9 All underground detention facilities shall be designed to be readily accessible for periodic inspection and maintenance from the surface without the need to perform confined space entry. Providing pre-treatment to remove sediments before or at the entrance of the underground detention facility to improve water quality and/or improve maintainability should be considered during the design. 9.2.11 Trash Racks Outlet structures shall be equipped with an appropriate trash rack. The trash rack shall be in accordance with the VA MP Clearinghouse. 9.3 Environmental Impacts Environmental impacts shall be carefully considered when siting stormwater detention facilities. Siting basins in low lying areas with potentially environmentally sensitive areas requires careful consideration, coordination, approval, and permitting with local, state, and federal agencies to evaluate the suitability of constructing in these areas. Environmentally sensitive areas include, but are not limited to wetlands, shallow marshes, jurisdictional waters, natural watercourses, wildlife habitat, etc. and may be protected by state and/or federal laws. With careful planning, it may be possible to incorporate wetland mitigation into the basin design. Construction of stormwater basins or modifications to existing basins shall comply with all applicable laws and regulations. The applicant is responsible for procuring all necessary permits, such as US Army Corps of Engineers and Virginia DEQ Wetland Permits, Virginia DEQ VPDES Permits, VSMP Permits, etc., prior to beginning construction. Copies of all permits shall be provided to Roanoke County prior to a land disturbing permit being issued. See Chapter 12 for more information. Detention facilities shall be coordinated with a watershed or regional plan for managing stormwater runoff, if available. 9.4 Maintenance Requirements For the post -construction maintenance of stormwater detention facilities, see Chapter 14. COUNTY OF ROANOKE x/1/16 9-8 STORMWATER DETENTION ENERGY DISSIPATION Chapter 10 - Energy Dissipation CHAPTER 10 Outlet protection for culverts, storm drains, BMP outlets, and steep open channels is essential to preventing erosion from damaging downstream channels and drainage structures. Erosion problems at culverts or at the outlet from detention basins are a common occurrence. Determination of the flow conditions, scour potential, and channel erosion resistance shall be standard procedure for all designs. Outlet protection can be a channel lining, structure, or flow barrier designed to lower excessive flow velocities and prevent erosion and scour. Outlet protection shall be employed whenever the velocity of flow at a pipe or open channel outlet exceeds the erosive velocity of the immediate downstream reach. Energy dissipation may take the form of the following: • Erosion control stone -lined channels; • Riprap outlet basins; or • Concrete baffled outlets. 10.1 References Except where more stringent requirements are presented in this Design Manual, energy dissipators shall comply with VDOT and other state requirements. The primary design references are the VDOT Drainage Manual and the VA E&SC Handbook. Other appropriate references include: • VDOT Standards • VA SWM Handbook • FHWA Design of Riprap Revetment HEC No. 11 (Pub. No. FHWA-IP-89-016 1989/2000) • FHWA Hydraulic Design of Energy Dissipators for Culverts and Channels HEC No. 14 (Pub. No. FHWA-EPD-86-110 Sept. 1983 & FHWA-IF-00-02 2000) • U.S. Dept. of the Interior — Bureau of Reclamation: Hydraulic Design of Stilling Basins and Energy Dissipators (Engineering Monograph No. 25) COUNTY OF ROANOKE q444x/l/16 10-1 ENERGY DISSIPATION ENERGY DISSIPATION CHAPTER 10 • U.S. Dept. of the Interior — Bureau of Reclamation: Design of Small Canal Structures 10.2 Design Methodology and Criteria 10.2.1 Outlet Velocity Where the outlet velocity from culverts, storm drain outfalls, or open channels is high, and channel or pipe modifications cannot adequately reduce the velocity, energy dissipation may be necessary. See the VDOT Drainage Manual Sections 7.4.6 and 8.3.2 for methodologies to determine design outlet velocities from open channels, culverts, and storm drains. For the calculation of open channel velocity, see Chapter 5. For the calculation of exit velocity from culverts, see Chapter 6. For the calculation of exit velocity from storm drain pipes, see Chapter 7. 10.2.2 Erosion Control Stone The most common form of energy dissipation is the use of erosion control stone at the outlet. Protection is provided primarily by having sufficient length and flare to dissipate energy by expanding the flow. The outlet velocities are computed for the VDOT design discharge. mid the 25 year diseha+ge. Wh:,.he , ,.i,.e4y is .r Where a pipe discharges into a channel, the apron shall extend across the channel bottom and shall extend up the bank to a depth of one foot above the maximum tailwater depth from the design storm event. The dimensional requirements of the erosion control stone apron shall be determined using the graphical curves in the VA E&SC Handbook. Generally, the use of erosion control stone for energy dissipation is limited to a maximum velocity of 19 feet per second. Alternative means of energy dissipation shall be required where the discharge velocity is greater than 19 feet per second. Alternative means include riprap outlet basins or concrete baffled outlets. The use of alternative means of energy dissipation requires the approval of VDOT when located in a VDOT right-of-way. 10.2.3 Riprap Outlet Basins COUNTY OF ROANOKE q444x/l/16 10-2 ENERGY DISSIPATION ENERGY DISSIPATION CHAPTER 10 A riprap basin is a depressed area of riprap placed at the outlet of a high velocity culvert, storm drain outlet or open channel. The riprap reduces the exit velocity by expanding the flow over the riprap length and width and forming a hydraulic jump. For the design of riprap basins, refer to the VDOT Drainage Manual. Dissipator geometry may also be computed using the "Energy Dissipator" module that is available in the computer program FHWA HY8, Culvert Analysis. Details of the riprap basin energy dissipator are included in Appendix 10A. 10.2.4 Baffled Outlets A baffled outlet usually consists of a concrete box structure with a vertical hanging concrete baffle and an end sill. Several variations of concrete baffled outlets have been published by VDOT and other state and local transportation and stormwater management agencies. A typical schematic of baffled outlets are shown in Appendix IOC. Baffled outlets are usually used when very high exit velocities exist at piped or channel transitions. Baffled outlets function by dissipating energy through impact of the water hitting the baffle and through the resulting turbulence. A tailwater depth is not required for adequate energy dissipation, but will help smooth the outlet flow. This type of outlet protection may be used with outlet velocities up to 50 feet per second. Baffled outlets are not included in state guidance handbooks. Hydraulic design procedures for baffled outlets may be found in the U.S. Department of Interior, Bureau of Reclamation, Design of Small Canal Structures, 1978 and are as follows: Step 1: Determine input parameters, including: H = _—Energy head to be dissipated, feet (can be approximated as the difference between --channel invert elevations at the inlet and outlet). Where: Q = Design discharge, cubic feet/second v = Theoretical discharge velocity determined from 2 g H, feet/second A = Flow area, Q / v, feetz COUNTY OF ROANOKE q444x/l/16 10-3 ENERGY DISSIPATION ENERGY DISSIPATION CHAPTER 10 d = Flow depth entering the basin, ft Fr = Froude number = v / ( g d )0 5, dimensionless g _Gravitational constant = 32.2 feet/second2 Step 2: Calculate the minimum basin width, W, in feet, using the following equation: W / d = 2.88 (Fr)"" Where: W = minimum basin width, feet d = depth of incoming flow, feet Fr = Fronde number = v / ( g d )0s The limits of the W/d ratio are from 3 to 10, which corresponds to Fronde numbers 1 to 9. If the basin is much wider than W, flow will pass under the baffle and energy dissipation will not be effective. Sten 3: Calculate other basin dimensions as a function of W. Refer to the Schematic of Baffled Outlet in Appendix LOCA for other dimensions as a function of W and to identify variables that are used below in other steps. Sten 4: Calculate the reauired Drotection for the transition from the baffled outlet to the natural channel based on the outlet width. A riprap apron shall be added of width W, length W (or a 5 -foot minimum), and depth f (W/6). The side slopes shall be 1.5:1, and the median rock diameter shall be at least W/20. Sten 5: Calculate the baffled outlet invert elevation based on the expected tailwater. The maximum distance between expected tailwater elevation and the invert should be b+f or some flow will go over the baffle with no energy dissipation. If the tailwater is known and fairly controlled, the baffled outlet invert should be a distance ( b / 2 ) + f below the calculated tailwater elevation. If tailwater is uncontrolled, the baffled outlet invert should be a distance f below the downstream channel invert. COUNTY OF ROANOKE q4/44x/1/16 10-4 ENERGY DISSIPATION ENERGY DISSIPATION CHAPTER 10 Step 6: Calculate the outlet pipe diameter entering the basin assuming a velocity_ of 12 fps flowing full. Step 7: If the entrance pipe slopes steeply downward, the entrance pipe shall be turned horizontal for at least 3 feet before entering the baffled outlet. Step 8: If it is possible that both the upstream and downstream ends of the pipe will be submerged provide an air vent approximately 1/6 of the pipe diameter near the upstream end to prevent pressure fluctuations and possible surging flow nnnditinnc 10.2.5 Energy Dissipator for Paved Areas For energy dissipation from velocities from paved channels or flumes, use VDOT Standards. Schematics of energy dissipators for paved flumes has been included in Appendix IOC. 10.2.6 Additional Energy Dissipators For additional energy dissipators, refer to FHWA HEC No 14 entitled, Hydraulic Design of Energy Dissipators for Culverts and Channels. 10.3 Installation Requirements Energy dissipators shall be installed and constructed according to all applicable FHWA, VDOT, and other state requirements and recommendations. 10.4 Easements Where an energy dissipater will be owned by a public jurisdiction or agency, a drainage easement must encompass the entire energy dissipator, and provide an additional area 10 feet wide around the entire energy dissipator to provide for maintenance. 10.5 Environmental Impacts Construction or modifications to energy dissipation structures shall comply with all applicable laws and regulations. The applicant is responsible for procuring all necessary permits, such as US Army Corps of Engineers and VA DEQ Wetland Permits, etc. 10.6 Maintenance Requirements The permittee is responsible for maintenance of energy dissipation structures until construction is complete, including final clean up and site stabilization, to the satisfaction of the County. After the completion of construction, property owners or responsible COUNTY OF ROANOKE q444x/l/16 10-5 ENERGY DISSIPATION ENERGY DISSIPATION CHAPTER 10 parties are responsible for maintenance of all energy dissipation structures located in private easements. COUNTY OF ROANOKE q444a/1/16 10-6 ENERGY DISSIPATION ENERGY DISSIPATION APPENDIX 10A AIDS FOR ENERGY DISSIPATION DESIGN FROM VDOT DRAINAGE MANUAL Figure 8E-1, Details of Riprap Basin Energy Dissipator Figure 8E-3, Riprap Basin Design Checklist APPENDIX 10A COUNTY OF ROANOKE q444a/1/16 1OA-1 ENERGY DISSIPATION ENERGY DISSIPATION APPENDIX 10A COUNTY OF ROANOKE q444a/1/16 1OA-2 ENERGY DISSIPATION ENERGY DISSIPATION Chapter 8 — Culverts APPENDIX 10A Appendix 8E-1 Energy Dissipation BISS1PArOR POOL MROR IB6,oRa ry >�+. In, +xOr£Pa OF •M'SE C I Z TOP OF .. 4 TOP OF RPRM TOP 6F NATIIFAL Jl E CHwNEL r, rw ZCNTPL PIPE CULVERT Wn= BARREL WIDTH F111 OR OR T, s+amu. ABOUT � � ]tl yo OR Sa �,yV, L5�a 1Sft. Mw. 2d� OR yaya OP. rsd,,,x. 15c,„,,. THICKENED OR SLOPING H%RlZaiuru � � TOE OPTIOI CONSTRUCT CE SECTION IF DOWNSTREAM CHANNEL DEGRADATION IS A:VTICIPA7CD. 6� A� B� flERM - FaTe B HALF PLAN BERwa ns 2tlsp OR i. S1 uN�, xp TGRN [MANNiL E Eita�AlETO Tw5 SEC. �A-A Bf KFILL WITH RIPRAP SEC. C -C 1 3tl'o � 2 I • � I,Stluu_ % .EAS R IJIPEL AS KwIRED T4 SUPPORT RIFF AP Td SOVPORT RWRrP . Yf_a OH I.SGu,u Ef ACVLQ TO 1 LINE. 80LKF6L -11 RIPRA° SEC - 13-e SEC.D-D NOTE A - IF E%IT VELOCITY OF BASIN IS SPECIFIEO,E%TEND BASIN AS REBURIED TO OBTAIN SUFFICIENT CROSS-SECTIONAL AREA AT SECTION A -A 5UCH THAT Qd ACROSs SECTION AREA AT SZCA-A] S?LC.FIEO EXIT VELOCITY. NOTE B - WARR BASIN TO CONFORM TO NATIJRAJ_ STREAM CHANNEL. TOP OF RIPRAP IN FLOOR OF BASIN SHOULD BE AT SHE SAME ELEVATION OR LOWER THAN NATURAL CHANNEL B07TOM AT SEC. A -A Figure 8E-1. Details of Riprap Basin Energy Dissipator 8E-4 .1 13 VDOT D.i-g. 114-1 COUNTY OF ROANOKE q444a/1/16 1OA-3 ENERGY DISSIPATION OF •M'SE �� �.�' z Jl E NOTE; Wo= DIAMETER FOR F` R// I APR�u PIPE CULVERT Wn= BARREL WIDTH F111 TY Zn d-RVDPT T, s+amu. ABOUT � � BOX CULVERT w<< SPAN OF PIPE -ARCH CULVERT _ H%RlZaiuru � � HALF PLAN BERwa ns 2tlsp OR i. S1 uN�, xp TGRN [MANNiL E Eita�AlETO Tw5 SEC. �A-A Bf KFILL WITH RIPRAP SEC. C -C 1 3tl'o � 2 I • � I,Stluu_ % .EAS R IJIPEL AS KwIRED T4 SUPPORT RIFF AP Td SOVPORT RWRrP . Yf_a OH I.SGu,u Ef ACVLQ TO 1 LINE. 80LKF6L -11 RIPRA° SEC - 13-e SEC.D-D NOTE A - IF E%IT VELOCITY OF BASIN IS SPECIFIEO,E%TEND BASIN AS REBURIED TO OBTAIN SUFFICIENT CROSS-SECTIONAL AREA AT SECTION A -A 5UCH THAT Qd ACROSs SECTION AREA AT SZCA-A] S?LC.FIEO EXIT VELOCITY. NOTE B - WARR BASIN TO CONFORM TO NATIJRAJ_ STREAM CHANNEL. TOP OF RIPRAP IN FLOOR OF BASIN SHOULD BE AT SHE SAME ELEVATION OR LOWER THAN NATURAL CHANNEL B07TOM AT SEC. A -A Figure 8E-1. Details of Riprap Basin Energy Dissipator 8E-4 .1 13 VDOT D.i-g. 114-1 COUNTY OF ROANOKE q444a/1/16 1OA-3 ENERGY DISSIPATION ENERGY DISSIPATION APPENDIX 10A -- C15$IPIT9R POOL All ~w To- Of UEAN raO Ff w TOP OF9IpRSP I! TOP O% NATURAL -- Jl �'#1ANNfL IC.'HI' ZCNTAL C[ y .7dFL ok 2a2d� e.S R OK15a Xd Ort 2tt 4R 1.Sdr.x. SEC. A -A u. rraeKEwEn OR SLOPING 10,,, OR I.]e'•.Y. • TQE �PTIRPEAL. Ov1'+5'ikuCT C SECTION ®.0.KFILL W17H RIrHAI+ 13 DcwNSTAEAM CNa IN+'eL. SEC. i TO 5%,'PPPAT RIPRAP DEGRADATION IS ANTICIPATED,. €x^.SNA-[ TO 7^.3 LINE, s,ERu A$ R;OLJF" OACKLILL MTX PJPR.'W dq SEC. B -B SEC. D -D WON T zf � 31 k'n' DIAMETER FOR 4 f Yr'"r I iwR •i PIPE MORi } wm. BARREL EL IVIE]TTI I rOR BOX CULVERT 1'r 7`1 i•uu, li SPANS OF PIP£ -ARCH I 1u: �"—'^� of CULVERT J G }TALE PLAN I � NOTE 5'-' A+i 1 I I SEC. A -A 9ERM 7d9E 10,,, OR I.]e'•.Y. • %[AV ATR 10 Trr$ ®.0.KFILL W17H RIrHAI+ eRR>w As HR�auuR+tc SEC. i TO 5%,'PPPAT RIPRAP €x^.SNA-[ TO 7^.3 LINE, s,ERu A$ R;OLJF" OACKLILL MTX PJPR.'W TG SUPPORT 11PAV 2eso OR SEC. B -B 5'-' A+i NOTE A IF Ex1T VELCll OF BASrM IS SPECIFIED, EYTEND BASIN AS REOURIE13 To 66TAIN SL)'FICENT CROSS-SECTIDNAL AR -0. AT $?,CTION A -A SUCH 7144T Cd../�IC159 SECTION AR -__A AT SEC. A -A) - SPECF00 i VELOcITr. NO -E B WARP 3ASIN TO CONFORM TC NATURAL STREAM CHA-41 L. TOE' OF Rill' IN FLOOR OF BASIN 5114 iD BEAT THE SSAhl ELEVATION OR LONER THM NATURAL. CHANNEL BOTTOM AT SEC, A -k Figure SE -1. Details of Riprap Basin Energy Dissipator COUNTY OF ROANOKE q4/44x/1/16 1OA-4 ENERGY DISSIPATION Commented [All illegible I I I I I I I 1 I I I I I I I I I I I I I I r 1 I 9ERM 10,,, OR I.]e'•.Y. • %[AV ATR 10 Trr$ ®.0.KFILL W17H RIrHAI+ SEC. i s,ERu A$ R;OLJF" TG SUPPORT 11PAV 2eso OR SEC. D -D NOTE A IF Ex1T VELCll OF BASrM IS SPECIFIED, EYTEND BASIN AS REOURIE13 To 66TAIN SL)'FICENT CROSS-SECTIDNAL AR -0. AT $?,CTION A -A SUCH 7144T Cd../�IC159 SECTION AR -__A AT SEC. A -A) - SPECF00 i VELOcITr. NO -E B WARP 3ASIN TO CONFORM TC NATURAL STREAM CHA-41 L. TOE' OF Rill' IN FLOOR OF BASIN 5114 iD BEAT THE SSAhl ELEVATION OR LONER THM NATURAL. CHANNEL BOTTOM AT SEC, A -k Figure SE -1. Details of Riprap Basin Energy Dissipator COUNTY OF ROANOKE q4/44x/1/16 1OA-4 ENERGY DISSIPATION Commented [All illegible I I I I I I I 1 I I I I I I I I I I I I I I r ENERGY DISSIPATION APPENDIX 10A Chapter 8 — Culverts Appendix 8E-1 Energy Dissipation RIPRAP BASIN TRIAL FINAL. 1 TRIAL Eq... Dcpth. ds D,(dE D� Fr.& No.. Fr Vdr h, "ID. 21 hfDp<q TAILWATER CHECK Taitwate, TW Equivalent d,pm, a, TW/dr IF T= > 0,75. nlalate riprop donnctream using Figura BEJ Dfw(4A,W" FA BASIN DIMENSIONS I F'EI71' Paul ]cngdl is the h,ger oI Imp 3W. Basin kngth is rhe larger of ISh, SW. App—ch Thickncss 3D„ Basin Thickness 2D, Figure 8E- 3. Riprap Basin Design Checklist BE -6 Of 93 VDOT Drainage Manual COUNTY OF ROANOKE q444x/l/16 1OA-5 ENERGY DISSIPATION ENERGY DISSIPATION APPENDIX 10A COUNTY OF ROANOKE q444a/1/16 1OA-6 ENERGY DISSIPATION ENERGY DISSIPATION I+rpjecr NQ. I7esigrict itevecu•er Tr f)CmGN VALUES (Figure 8F-2) Equi. ❑cr+:h. d, p.'de ❑a Fr M: ND. Fr lrrdr TAILWATER CHFCR Tail+ tier, TW EgU,%IIM aepA- a, Tway IF TWld, S 0.7%utYvr.ie norp dawnslfieam w0ne Frere SE -4 RIFRAP BASIN TRIAL I RNAL. I rRIA APPENDIX 10A Dare Bate 4a BAMl J DIMENSfOVS h'EIr ftxd de.Lth is dK 4i1hi dw, nrsir. Icngah a IShs me lamer uf� aw hppretsa dP�. BAMl J DIMENSfOVS h'EIr ftxd de.Lth is dK 4i1hi dw, nrsir. Icngah a IShs me lamer uf� aw hppretsa dP�. u Basin Threkn s 1 2Ci. 1 11 Figure BE. 3. Riprap Basin Design Checklist SE -6 Df id VDQ T Drainage Manual COUNTY OF ROANOKE q444a/1/16 1OA-7 ENERGY DISSIPATION ENERGY DISSIPATION APPENDIX 10B AIDS FOR ENERGY DISSIPATION DESIGN FROM VDOT ROAD AND BRIDGE STANDARDS Standard 114.01, Stone for Erosion Control APPENDIX 10B COUNTY OF ROANOKE x/l/16714 14 1OB-1 ENERGY DISSIPATION ENERGY DISSIPATION APPENDIX 10B �m w � s 0° F HHX m W I�in•ra x �$ I L'Y Jy� '( z A # gig; ~ Z 0 o �g [J j 2 d 43xe o wx.�i U $ 0 ri e = w z � m m m� a U in �s a D F U � C COUNTY OF ROANOKE %/1/167//1 4 1OB-2 ENERGY DISSIPATION 10100 Kei'/11 LW1611YLOW :\901 11]►f[IT0 APPENDIX 10C ENERGY DISSIPATION DESIGN SCHEMATICS Schematics of Baffled Outlet, from US Bureau of Reclamation, Design of Small Canal Structures (as used by the State of Georgia and State of Colorado) Standard Energy Dissipator for Use with Paved Flume, from VDOT Road and Bridge Standards Precast Energy Dissipator, from VDOT Road and Bridge Standards Level Spreader from VA DCR Stoimwater Specifications Various Energy Dissipators and Stilling Basins, from City of Knoxville, TN BMP Manual COUNTY OF ROANOKE q444x/l/16 10C-1 ENERGY DISSIPATION ENERGY DISSIPATION APPENDIX IOC VA CCR STORMWATER DESIGN SPECT FICATION NO.2 SHEET FLOW TO FILTER OR OPEN SPACE RIP RAP PLLINaE POLI RIPRAP APRON , KEY LEVEL SPREADER AYTO E)USTWn MADE CONCRETE LIP I LENGTH CF LEVEL SPFFADER I • LP TO BE 9ASED ON DESIGN FLow AND ALLOWABLE VELD TOP OF LEVEL SPREADER r SHALL 9E FLAT 1,3 IN GODRSE A.ROREOATE.' OR OTHER LNNG AS DESIGNED FOR STABILnY P{y{y VFW LIMA- SILNH tlR_tI] LIN rDW�VOCP DESIGN DISCHARGE . ria carr. nrarrrrwaa ' AAVJ 2�aa� FwFi rA �fiFT LFA3 l 3 %r11N +I 1IX MIN IN REOUWe-O STCM SZE Figure 24., Len el:Spreader. Pipe or Cliu erel F7oH^ to Filter Stri►r or Presen•ed Cheri Space Version 2.0, January 1, 2013 Page 8 o121 COUNTY OF ROANOKE q444a/1/16 10C-2 ENERGY DISSIPATION ENERGY DISSIPATION APPENDIX 10C SECTION Rock diameter for prof eciion= 1/20(W) Figure 4.5.41 Schematic of Baffled Outlet (Source: U.S. Npt- Df the Inlerior,10V* 4.5.22 Geargld Starmwater Managarrrynt Manual COUNTY OF ROANOKE q444a/1/16 1OC-3 Volume 2 (Technical Handbook) ENERGY DISSIPATION - - i coq L =/3 (W) SEG. A -A (w) �t 11 L PLAN -a--� Protection as re=ired I1 a= 172, 112 (WI SECTION Rock diameter for prof eciion= 1/20(W) Figure 4.5.41 Schematic of Baffled Outlet (Source: U.S. Npt- Df the Inlerior,10V* 4.5.22 Geargld Starmwater Managarrrynt Manual COUNTY OF ROANOKE q444a/1/16 1OC-3 Volume 2 (Technical Handbook) ENERGY DISSIPATION ENERGY DISSIPATION CDOT Drainage Design Manua! APPENDIX 10C Ener,T Dissipaters PLAN n, PLAN E 1 I t Ll 1p 1 t �^ a qrA ruN.s� FDOBLET qb El t V #I —t I� II M� x.20 m -S PLAN n, PLAN E 1 I t 6 —f0.29 m mAx.1 F I 1 t �^ a qrA ruN.s� FDOBLET qb I SECTION STILLING BASIN DESIGN O O S I z c b A c I ,4 n o 4n ti T 4 h,s h3 BEggIwG SECTION ALTERNATIVE END SILL Figure 11.7 USBR Type VI (Impact} Dissipater COUNTY OF ROANOKE q444a/1/16 1OC-4 ENERGY DISSIPATION ENERGY DISSIPATION APPENDIX 10C d N a n P W M au ao T 07 7 D W V) COUNTY OF ROANOKE q444a/1/16 1OC-5 ENERGY DISSIPATION Gl I~/� y 4 N iA I�it y Vhf N 1/� LLU z ¢1 m m m -SdSaVB !, o - -ba sada o -id Sada � N -za sada � i ¢�O -io sava J� V S �2 J� O� a S�� m ry n V u7 d N a n P W M au ao T 07 7 D W V) COUNTY OF ROANOKE q444a/1/16 1OC-5 ENERGY DISSIPATION y 4 � 0 O 00 O� sW m -SdSaVB !, -ba sada o -id Sada � N -za sada � i ¢�O -io sava J� V S �2 J� O� d N a n P W M au ao T 07 7 D W V) COUNTY OF ROANOKE q444a/1/16 1OC-5 ENERGY DISSIPATION ENERGY DISSIPATION APPENDIX 10C U 6 xx .9-1 .A- r w w> > W W a h.6 F APPENDIX 10C U 6 1-j i m e m _ F o ca Ewa jA - � M Ewa 7g c '�iYz r 4 ld Sw9l Jg APPENDIX 10C 1-j APPENDIX 10C COUNTY OF ROANOKE q444a/1/16 1OC-6 ENERGY DISSIPATION e o � Lu W F 2 W W m 4 u 6 N uj COUNTY OF ROANOKE q444a/1/16 1OC-6 ENERGY DISSIPATION ENERGY DISSIPATION APPENDIX !o COUNTY o ROANOKE SAA 1Oc7 ENERGY m»2&£o q §{ G a a Ld /[ ¥ ® / )\#§ \ G g § § « - & E § 9 / 2 { . . - - 0 m } \ - - . . , \ � m . : � COUNTY o ROANOKE SAA 1Oc7 ENERGY m»2&£o ENERGY DISSIPATION APPENDIX !o COUNTY o ROANOKE SAA mc, ENERGY m»2&£o � $! # � q � ql |`; \ ( |k� §y \` § § % k /| ; a » / k o E| N \ �| ^ / < « .� - � | E . a R � $ \ |§ i \ ||� COUNTY o ROANOKE SAA mc, ENERGY m»2&£o ENERGY DISSIPATION ACTIVITY: outlet Protection Chute blocks (size and shape vary) — Baffle piers, optional , see note I (size and shape vary) Sufficient depth for — hydraulic jump plus adequate freeboard End sill (may be dentated) Typical Stilline Basin At End of Paved Flume or Chute Computed normal flow culvert Concrete stilling basin v L flaffle5 w slow water down (see note 2) without cYcessive head loss Typical Stilling Basin Using Baffles and Elevation Drop Stagger baffle blocks laterally Typical Energy Dissipator - Baffle _Blocks _Within llcadwall APPENDIX 10C ES — 25 Securely fasten CMP Lee section with coupling bands or screws d }. .. �.. 4. n..w. J.. Support structure with sandbags or other materials to prevent movement Temporary CMP Eneru Dissipater Notes: I. This is the basic format for several types of stilling basins, USSR Type It basin does not contain baffle piers, but does have a dentated end sill. USBR Type IIl basin has baffle piers and a smooth undentated end sill. See 1IEC-14 for detailed design of concrete structures. 2. Concrete stilling basin should be approximately as wide as the downstream channel. Design baffles to retain sufficient srormwater to aet as a plunge pool for a wide range of flow values. Relies on sufflaient tailwater to halt flow velocity Typical Impact Energy Dissipater (Virginia DOT) NOT TO SCALE Figure ES -25-2 Various Energy Dissipators and Stifling Basins COUNTY OF ROANOKE q444a/1/16 10C-9 ENERGY DISSIPATION (NOT USED) Chapter 11 — (NOT USED) COUNTY OF ROANOKE '"44x/1/16 CHAPTER 11 (NOT USED) ENVIRONMENTALLY SENSITIVE AREAS CHAPTER 12 Chapter 12 - Environmentally Sensitive Areas Stormwater discharges to areas with features identified as environmentally sensitive may be subject to additional requirements, or may need to utilize or restrict certain stormwater management practices. The following type of areas are considered to be "environmentally sensitive": • Floodplain —Areas identified within a 100 -year recurrence interval flood plain. • Steep Slopes — Areas with a slope of 33 percent or greater. • Stream Buffers —Setbacks and vegetative buffers established adjacent to the Roanoke River as required by the County of Roanoke zoning ordinance or designated conservation area buffer zones at each bank of streams, ponds, lakes, wetlands, and stormwater BNWs. • Critical Erosion Areas — Areas with potential serious erosion problems as defined in the VA E&SC Handbook. These fall into two sub categories. o The erosion hazard is critical if the slope length exceeds the following criteria: 0-7% slope > 300 feet 7-15% slope > 150 feet >15% slope > 75 feet o Areas may be critical if the soils are highly erodible, as classified using the United States Department of Agriculture (USDA) Natural Resources Conservation Service (formerly Soil Conservation Service) methods, either Land Capability Classification IIIe, IVe, IV, VII, or VIII or with an erodibility index factor greater than 8. • Karst Geology — Areas where the underlying geologic conditions include caves and crevices which allow stormwater to infiltrate and quickly migrate and transport potential pollutants. • Hot Spots — Areas where a high potential for stormwater pollution may occur due to current or former activity on the site. • Jurisdictional Streams and/or Water — Waters regulated by U.S. Army Corps of Engineers (USACE) under Section 404 of the Clean Water Act. A jurisdictional determination (JD) is required that identifies and separates the Corps regulated areas from non-regulated areas. Disturbance in regulated areas requires a permit form USACE. JDs are typically good for 5 years after the determination has been made by COUNTY OF ROANOKE 9/ 44X41/16 12-1 ENVIRONMENTALLY SENSITIVE AREAS OWLTAR1410041WN1►:\1 W&IBWYY\IIW.1N R X11 MyY0II'M IPJ the USACE. Third party reports by qualified professionals will be accepted for jurisdictional stream delineation. • Wetlands- Wetlands regulated by U.S. Army Corps of Engineers (USACE) under Section 404 of the Clean Water Act. A iurisdictional determination (JD) is required that identifies and delineates wetlands. Disturbance in wetlands requires a permit form USACE. JDs are typically good for 5 years after the determination has been made by the USACE. Third party reports by qualified professionals will be accepted for wetland delineation. 12.1 References The following publications may be useful in providing guidance when performing construction, establishing development limits, and developing appropriate strategies and design features to address the special concerns related to environmentally sensitive areas: • VDOT Drainage Manual • VA E&SC Handbook • VA SWM Handbook • Virginia Department of Conservation and Recreation, Technical Bulletin No. 2, Hydrologic Modeling and Design in Karst • International Building Code • The Development of the Land Capability Classification (reprinted from Readings in the History of the Soil Conservation Service), Douglas Helms, Soil Conservation Service, 1992 • Clean Water Act Section 404 • River & Harbors Act of 1899 Section 10 • FEMA Flood Map Service Center • Flood Insurance Rate Map (FIRM) COUNTY OF ROANOKE 9/ 44X41116 12-2 ENVIRONMENTALLY SENSITIVE AREAS ENVIRONMENTALLY SENSITIVE AREAS CHAPTER 12 12.2 Floodplains The purpose of floodplain management is to regulate the use of the floodplains in order to protect life and property, prevent sedimentation and pollution of water resources, and to prevent or protect against the general degradation of the environment. Floodplains and their regulatory requirements are generally based on the stream flows generated by a 100 -year frequency storm and existing land development conditions. However, storms and future land development can generate flows of greater magnitude and flooding above and beyond these limits. For this reason, additional vertical and horizontal setbacks from the floodplain limits are strongly encouraged to account for future development within the upstream drainage area and to serve as a factor of safety for larger flood events. Floodplains include: • Areas identified within a 100 -year recurrence interval floodplain as identified by the Federal Emergency Management Agency (FEMA). These areas have been identified as the Floodplain Overlay District by the County of Roanoke Zoning Ordinance. • Areas identified within a 100 -year interval floodplain as identified by an applicant floodplain study. Management of floodplains in Roanoke County shall be in accordance with the requirements published in the County of Roanoke Zoning Ordinance. Under no conditions, shall the land disturbance activity adversely affect the capacity of channels, floodways, ditches, or any drainage facility or system. The lowest floor elevation of any new residential structure, as defined in the County of Roanoke Zoning Ordinance Section 30-28, shall be at least 2 feet above the base flood elevation. The lowest floor elevation of any new non-residential structure shall be at least 1 foot above the base flood elevation unless the structure is floodproofed. The elevation of the lowest floor shall be certified by a ",.,.'Registered *ufv-& e Surveyor or professional engiixeer-Engineer on an Elevation Certificate after the lowest floor is installed. Grading and cut and fill operations within the 100 -year flood plain are discouraged and must be approved by the County of Roanoke. Activity within the floodplain must also be coordinated with other regulatory requirements and agencies. These may include erosion and sediment control, stream buffer protection, FEMA, VMRC, U.S. Army Corps of Engineers, Virginia DEQ, and others. COUNTY OF ROANOKE 9/ 44X41/16 12-3 ENVIRONMENTALLY SENSITIVE AREAS ENVIRONMENTALLY SENSITIVE AREAS CHAPTER 12 Construction of stormwater management impoundment structures within a floodplain shall be avoided to the extent possible. Where this is unavoidable, all stormwater management facility construction shall be in compliance with all applicable regulations under the National Flood Insurance Program, 44 CFR Part 59, and in accordance with the County of Roanoke Zoning Ordinance. The County does not have the authority to alter or modify the flood limits and/or elevations established by FEMA. Should an applicant flood study indicate any alteration in FEMA's limits and/or elevations, then the applicant must contact FEMA and obtain a map revision. 12.2.1 Applicant Flood Study Requirements A flood study, prepared by a Professional Engineer, must be prepared and submitted, by the applicant, for all areas where the drainage area is 100 acres or greater, and there are no detailed flood profiles or elevations from a FEMA Flood Insurance Study. There are two levels of studies. A detail study is required, if any development is proposed within the floodplain. Development includes grading and road crossings. A limited detail study is acceptable, if no development is proposed within the floodplain and the purpose of the study is to avoid the floodplain. A detail study involves a rigorous detailed hydrologic and hydraulic study of a flooding source reach. The typical riverine detail study includes the following minimum steps: • Field survey of stream and floodplain cross-sections • Field survey of all hydraulic structure crossings. • Collection of historical high water mark elevations and model calibration/verification, if data is available. • Detailed hydrologic & hydraulic modeling/computations • Establishment of the FEMA regulatory Floodway • Other tasks meeting all FEMA Guidelines and Specifications for Flood Hazard Mapping Partners A limited detail study may be performed when development is to occur adjacent to, but not in the existing floodplain. In most limited detail modeling, local regional regression equations along with a HEC -RAS hydraulic model will be developed. The major difference between the HEC -RAS models for the limited detail study and the detail study will be the amount of field survey information collected in the field and used to create the model and the amount of time spent on calibration to historical flood elevations. The limited detail models typically include no field survey data, and floodways are typically not computed. The COUNTY OF ROANOKE g414 x/1/16 12-4 ENVIRONMENTALLY SENSITIVE AREAS ENVIRONMENTALLY SENSITIVE AREAS CHAPTER 12 methods for limited detail study are further outlined in the FEMA Guidelines and Specifications for Flood Hazard Mapping Partners In addition, the following information and items are required when an applicant flood study is submitted to Roanoke County for review: • The flood study shall be based on the ultimate land use conditions as - - Formatted: Font: Bold published in the most recent Comprehensive Plan for upstream areas. Structure locations shall be based on the ultimate build out data. • The flood study shall be prepared by a registered Professional Engineer licensed to practice engineering in Virginia, sealed, signed, and dated. • Assuming that sedimentation or scour may occur during the storm event is not acceptable. • The flood study shall compare pre- and post -development conditions to verify that the proposed development will not increase the 100 year flood elevation more than 1 foot at any point. • The flood study shall consider backwater conditions, local obstructions and, where required by the County of Roanoke Department of Community Development, the partial or complete failure of any enclosed drainage system. Consideration must be given to the overflow path, to ensure that no structures will flood in the event of system failure. • The flood study shall analyze the 100 -year flood path for all new development. • A digital version of the 100 -year flood limits and cross sections must be sepplied-pmL:ided to the County. The study and supporting data will become .public information. The site plan digital file shall be in ACAD format and tied to the correct State Plane Coordinate. • Cross sections from the study must be indicated on the site plans submitted as a part of the development review package. 12.2.2 Floodplain Delineation The limits of floodplain floodways shall be staked and flagged in the field prior to any land disturbance activities and they shall remain undisturbed during construction. After the completion of construction, the limits of floodplain COUNTY OF ROANOKE 9/ 44X41/16 12-5 ENVIRONMENTALLY SENSITIVE AREAS ENVIRONMENTALLY SENSITIVE AREAS CHAPTER 12 floodways shall be checked to verify that no unauthorized filling has taken place in the floodway. The limits shall be shown on the plan and labeled with a point number and either a northing and casting or latitude and longitude points. Place floodplain limits and floodways on the final plats submitted for each property. All subdivision plats and site plans located within the floodplain in whole or in part shall include base flood elevation data. 12.3 Steep Slopes Special precautions and guidelines are required for development in areas having steep slopes, defined as thirty-three and one third percent (33.3%) or greater. These precautions and guidelines address the increased potential for soil erosion, sedimentation, water pollution and septic disposal problems associated with the development of areas with significant topographical relief. Unrestricted development of steep slopes may result in: • Rapid and/or large-scale movement of soil and rock; • Rapid and excessive stormwater run-off, • Deposition of eroded material leading to siltation of natural and man-made bodies of water; • Loss of aesthetic resource; and • Greater travel distance of septic effluent in the event of septic system failure. 12.3.1 Development Restrictions Land -disturbing activities on steep slopes are regulated by Chapter 8.1 of the County Code, "Erosion and Sediment Control and Steep Slope Development Ordinance of the County of Roanoke, Virginia." If the grade of a site is greater than 33.3%, refer to the International Building Code for steep slope development requirements. 12.3.2 Design Standards No land disturbance of steep slopes may occur without a geotechnical study that concludes that the land disturbance will result in a stable finished slope. For the requirements of a geotechnical study, see County of Roanoke Erosion and Sediment Control and Steep Slope Ordinance. COUNTY OF ROANOKE q444x/1/16- 12-6 ENVIRONMENTALLY SENSITIVE AREAS ENVIRONMENTALLY SENSITIVE AREAS CHAPTER 12 Land disturbance of steep slopes require the preparation and submittal to the County of as -built plans showing that the finished geometry is in substantial conformity with the approved site plan. Site grading and measures required to control stormwater runoff shall collect and carry storm drainage away from the steep slope to the extent possible. If concentrated runoff is to be discharged in areas of steep slopes, adequate protection must be installed to prevent channel erosion and energy dissipation shall be used at the base of the steep slope to prevent erosion where the flow transitions to a shallower slope. The use of a closed conduit storm drain should be considered in accordance with Chapter 7. 12.4 Stream Buffers Stream buffers are established to provide a naturally vegetated strip of land adjacent to stream. This buffer protects the stream from encroachment by development, preserves the water, recreational, and environmental resources, protects the floodplain and floodway, retards runoff, and helps improve the water quality of stream by preventing erosion and filtering non -point source pollution from runoff. The establishment of stream buffers as a water quality measure is encouraged by the County of Roanoke. Requirements for stream buffers shall be in accordance with Section 30-75 of the County of Roanoke Zoning Ordinance- Roanoke River Conservation and Overlay District. Additionally, the development must meet the required stream setbacks as outlined in Section 30-75-5. 12.5 Critical Erosion Areas Critical erosion areas, if cleared of vegetation and exposed to the elements of nature, may experience significant erosion and sedimentation problems, including a significant loss of topsoil. These soils tend to be located on hillsides and areas with steep slopes, and adjacent to river valleys and tributaries. Critical erosion areas include 'we s4 ea'egafie : • The erosion hazard is critical if the slope length exceeds the following criteria: 0-7% slope > 300 feet COUNTY OF ROANOKE 9/ 44X41/16 12-7 ENVIRONMENTALLY SENSITIVE AREAS ENVIRONMENTALLY SENSITIVE AREAS CHAPTER 12 7-15% slope > 150 feet >15% slope > 75 feet Critical erosion areas shall be indicated on the Erosion and Sediment Control Plan. To the— - - jFormatted: indent: Left: o.s", First line: o" extent feasible, disturbance of critical erosion areas shall be avoided or minimized. Where critical erosion areas are disturbed, their protection and stabilization shall specifically be addressed by the Erosion and Sediment Control Plan and the Stormwater Management Plan. 12.6 Karst Geology Developers and Designers are cautioned that construction in karst geology requires special care and study; and that they are responsible to ensure that all appropriate investigations are performed by licensed geotechnical engineers or geologists to ensure long-term soil stability for proposed buildings and site improvements. Although proper study of site conditions is the responsibility of the Developer and Designer, Roanoke County may, at its discretion, require a geotechnical investigation, prepared by a licensed geotechnical engineer or geologist, on a case by case basis. COUNTY OF ROANOKE 9/ 44X41/16 12-8 ENVIRONMENTALLY SENSITIVE AREAS ENVIRONMENTALLY SENSITIVE AREAS CHAPTER 12 Karst is an underlying geology which is common in Roanoke County where the underlying rock is predominantly soluble limestone or dolomite creating caves, crevices, and other cavities in the rock. Stormwater may infiltrate to the karst geologic rock and quickly drain through the open cavities. In addition to providing a quick transport mechanism for potential stormwater pollutants, this may create quick erosion of the limestone, potentially causing sinkholes or other surface sloughing. Identification of karst geology shall be based on local geology and soils maps, aerial photography, and site visits by a person familiar with karst geology. Karst areas present problems with conventional hydrologic stormwater models, creating poor representation of runoff rates as most models do not have allowances for losses through sinkholes, crevices, or caves. A site : esti ati0r i t ,8" ,:,.j 4,.:,1,.,14:4, afeas impaeted byy.1,•..4 geology R44 A PARR h 1......1,1 044 IF -Wal ,. ,.18gy Mid fflffpS, affial P1,,.4Ogr-.1pl+y Hj ..:40 34S4.. by .. See DCR Technical Bulletin #2, Hydrologic Modeling and Design in Karst for additional information on identification, and modeling requirements for areas in karst geology. Recommended practices include: • Design the site to take maximum advantage of topography. • Minimize site disturbance, cuts, fills, and drainage alterations. • Minimize the impervious surface. • Stormwater conveyance structures shall be designed to dissipate overland flow over the largest areas possible. Avoid concentration of flows and ponding. • Stormwater management facilities located in karst areas shall be installed with a liner. T4q M- ,...*:,... A ,1:1:ties m fiat be 1,.,1..4,1,1 4 ka fs4 geology 1 :41,,.114 .. 1:4..1.1,1 A ,1:1:ties or -.14.14«..r:,... 4444U..: AFRA ., 41,..4 41„1 !`,111.14., beli,11„1s has b..«..4 geeleOnly BMP structures approved for karst areas by the VA BMP Clearinghouse will be allowed for installation. 12.7 Stormwater Hot Spots Stormwater discharges from land uses or activities with higher potential pollutant loadings, known as "hotspots", may require a greater level of stormwater treatment or the use of specific structural BMPs and pollution prevention practices. Greater COUNTY OF ROANOKE 9/ 44X41/16 12-9 ENVIRONMENTALLY SENSITIVE AREAS ENVIRONMENTALLY SENSITIVE AREAS CHAPTER 12 concentrations of sediment, hydrocarbons, traces metals, pesticides, and other toxics than are found in typical stormwater runoff may qualify a site for designation as a hot spot. The following land uses and activities may be stormwater hotspots: 1. Vehicle salvage yards and recycling facilities; 4- 2. 2. Vehicle fueling stations; 2 3. Vehicle service and maintenance facilities; 4. Vehicle and equipment cleaning facilities; 4 5. Fleet storage areas (bus, truck, etc); .- - - Formatted: Indent: Left: 1", No bullets or numbering - - Formatted: List Paragraph, No bullets or numbering, Adjust space between Latin and Asian tent, Adjust space between Asian tent and numbers - - Formatted: Indent: Left: 1", No bullets or numbering - - Formatted: List Paragraph, No bullets or numbering, Adjust space between Latin and Asian tent, Adjust space between Asian tent and numbers 9. Outdoor loading and unloading facilities; L 10. Public works storage areas; 44. 11. Facilities that generate or store hazardous materials; 11 12. Commercial container nursery; 13. Golf courses; 13- 14. Chemical storage; and 44- 15. 415. Dry cleaning operations. 12.7.1 Design Restrictions COUNTY OF ROANOKE 9/ 44X41/16 12-10 ENVIRONMENTALLY SENSITIVE AREAS - - Formatted: List Paragraph, No bullets or numbering, Adjust space between Latin and Asian text, Adjust space between Asian text and numbers - - Formatted: Indent: Left: 1", No bullets or numbering - - Formatted: List Paragraph, No bullets or numbering, Adjust space between Latin and Asian text, Adjust space between Asian text and numbers - - Formatted: Indent: Left: 1", No bullets or numbering - - Formatted: List Paragraph, No bullets or numbering, Adjust space between Latin and Asian text, Adjust space between Asian text and numbers - - Formatted: Indent: Left: 1", No bullets or numbering - - Formatted: Indent: Left: 1", No bullets or numbering Formatted: French (France) 6. Industrial sites (for SIC codes contact VA DEQ); - - Formatted: Indent: Left: 1", No bullets or numbering 7. Marinas (service and maintenance areas); - - Formatted: List Paragraph, No bullets or numbering, Adjust : space between Latin and Asian tent, Adjust space between Asian tent and numbers 8. Outdoor liquid container storage; - - Formatted: Indent: Left: 1", No bullets or numbering 9. Outdoor loading and unloading facilities; L 10. Public works storage areas; 44. 11. Facilities that generate or store hazardous materials; 11 12. Commercial container nursery; 13. Golf courses; 13- 14. Chemical storage; and 44- 15. 415. Dry cleaning operations. 12.7.1 Design Restrictions COUNTY OF ROANOKE 9/ 44X41/16 12-10 ENVIRONMENTALLY SENSITIVE AREAS - - Formatted: List Paragraph, No bullets or numbering, Adjust space between Latin and Asian text, Adjust space between Asian text and numbers - - Formatted: Indent: Left: 1", No bullets or numbering - - Formatted: List Paragraph, No bullets or numbering, Adjust space between Latin and Asian text, Adjust space between Asian text and numbers - - Formatted: Indent: Left: 1", No bullets or numbering - - Formatted: List Paragraph, No bullets or numbering, Adjust space between Latin and Asian text, Adjust space between Asian text and numbers - - Formatted: Indent: Left: 1", No bullets or numbering ENVIRONMENTALLY SENSITIVE AREAS CHAPTER 12 Stormwater BMP practices having an infiltration component located in stormwater hotspot areas shall be provided with adequate pretreatment or storage areas to preclude pollutants from the infiltration area. The property owner must conform with all applicable laws and regulations relevant to any chemicals or hazardous materials used on these sites. Industrial operations shall be conducted to minimize exposure of chemical storage containers to stormwater, and contain any runoff as required by law where this can not be avoided. These sites must also meet DEQ6R VSMP and DEQ VPDES permit requirements, where applicable. 12.7.2 Golf Course Development Golf courses, while maintaining impervious area and natural buffers allow for the introduction of nutrients into stormwater through fertilizers and chemicals into stormwater through the use of pesticides and herbicides. Design of golf courses, public or private, should meet the following performance standards: 1. Managed turf should be reduced by including areas of rough devoted to native plants, natural environments, and wildlife habitat enhancement; 2. An Integrated Pest Management and nutrient management plan should be prepared and followed; 3. Native or naturalized landscaping should be used to the extent possible; 4. Natural vegetation and trees along streams should be retained to the extend possible; 5. Stream crossings should be minimized; 6. Irrigation, drainage and retention systems should be designed to provide for efficient use of water and the protection of water quality; 7. Water reuse strategies should be employed when feasible; COUNTY OF ROANOKE 9/ 44X41/16 12-11 ENVIRONMENTALLY SENSITIVE AREAS ENVIRONMENTALLY SENSITIVE AREAS CHAPTER 12 Adherence to the "Environmental Principles of Golf Courses in the United States" published by the Center for Resource Management is encouraged. A Nutrient Management Plan should be developed by a certified Nutrient Management Planner consistent with DCR's Nutrient Management Training and Certification Regulations. COUNTY OF ROANOKE 9/ 44X41/16 12-12 ENVIRONMENTALLY SENSITIVE AREAS ENVIRONMENTALLY SENSITIVE AREAS APPENDIX 12A APPENDIX 1-A prLSICIN AIDS COUNTY OF ROANOKE q444x/1/16 12A-1 ENVIRONMENTALLY SENSITIVE AREAS ENVIRONMENTALLY SENSITIVE AREAS APPENDIX 12A COUNTY OFROANOKE q444x/1/16 12A-2 ENVIRONMENTALLY SENSITIVE AREA II full SII Ifllli Innn rnnnl S nniul hunll .�unlu nnlll ♦Willa Knurl tnruu ullll �ulrli tullli, Inlli ♦11111 , �Illil Illli� tlliii Nllli� Illii t� i v � i t� f� h� t " I� Formatted ,'(Formatted 2 I Formatted 3 I Formatted 4 I Formatted 5 Formatted 6 I' Formatted I' Formatted g I Formatted g Formatted 10 / Formatted 11 / Formatted 12 Formatted 13 Formatted 14 —11 .. Formatted . 15 Formatted r F16�1 i Formatted 17 —11 Formatted lg i Formatted lg i Formatted 20 Formatted 21 Formatted 22 —11 Formatted 23 Formatted r2411 Formatted 25 FormattedF�T2611 Formatted 27 Formatted 2g Formatted 29 Formatted 30 Formatted 31 Formatted 32 Formatted 33 Formatted 34 Formatted ..35 Formatted . 36 Formatted F3717 Formatted 38 Formatted r F39�1 Formatted 40 Formatted 41 Formatted 42 Formatted 43 Formatted 44 Formatted 45 Formatted 46 Formatted 47 Formatted 48 —11 Formatted 49 Formatted 50 Formatted 51 Formatted 52 GEOTECHNICAL STUDIES Chapter 13 - Geotechnical Studies (RESERVED) COUNTY OF ROANOKE '"44x/1/16 13-1 CHAPTER 13 GEOTECHNICAL STUDIES MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 Chapter 14 - Maintenance of Stormwater Management Facilities Proper maintenance of stormwater management facilities is essential to ensure proper long-term operation of these systems. Possible problems which may develop without proper maintenance include: • Stormwater structures may become clogged with debris reducing flow capacity which may cause upstream flooding; • Stormwater storage facilities may fill with sediment or debris reducing storage capacity and diminishing the ability of the facility to lower storm flows which may result in flooding downstream; • BMPs may not remove pollutants at the design levels required to meet the water quality requirements. If vegetation is not periodically cut and removed, it may release nutrients back into the environment, negating their water quality benefit. Stormwater management facilities include detention and retention basins, bioretention, grassed swales, and other BMPs that are intended to control stormwater runoff and change the characteristics of that runoff including, but not limited to, the quantity and quality, the period of release or the velocity of flow. Stormwater management facilities also include pipes and open channels, where the pipes and open channels are integral parts of the BMP (e.g. the pipes in a detention basin that convey flow from the outlet structure through an embankment to the discharge), and where the pipes and open channels are being used as BMPs to store or treat stormwater. Pipes (culverts and storm drains) and open channels that do not store or treat stormwater and are not an integral part of a BMP are storm drainage systems and not stormwater management facilities. Maintenance of stormwater management facilities are addressed in this Chapter. Maintenance of culverts, storm drains, and open channels that are not stormwater management facilities are addressed in their respective chanters. The maintenance guidance provided in this chapter is the routine maintenance that should be anticipated for typical nonproprietary BMPs; however, it is not meant to be all-inclusive. It is the applicant's responsibility to provide a project specific maintenance plan and schedule as part of the maintenance agreement. Information on BMP maintenance may also be found in the y^ 91.444 u,.raw221 v and toe Bean Clear-:n,.i.,.use website- ra f em *' Manufacturer's literature. 14.1 Responsibility for Maintenance COUNTY OF ROANOKE q 1 X11/16 14-1 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 Maintenance of stormwater management facilities is the responsibility of the permittee during construction until all work is completed, including final clean up and site stabilization, to the satisfaction of the County. At the completion of construction, maintenance of stormwater management facilities becomes the responsible party or land owner's responsibility in accordance with the executed Maintenance Agreement. The County is not responsible for maintaining private stormwater management facilities. 14.2 Maintenance Agreements A legally binding maintenance agreement specifying the parties responsible for the proper maintenance of all stormwater management facilities shall be secured prior to issuance of any permits for land disturbance activities. Responsibility for the operation and maintenance of stormwater management facilities, after the completion of construction, shall remain with the responsible party or property owner and shall legally pass to any successor or owner. The maintenance agreement shall include a project specific appendix that lists all stormwater management facilities present on the property; the minimum frequency of inspections and maintenance, and the routine maintenance that is to be performed for each stormwater management facility. The project specific appendix to the maintenance agreement is to be prepared by the applicant and submitted to the County with the Stormwater Management Plan for review. The information contained within the VA SWM Handbook-aH4. the VA BMP Clearinghouse, and Manufacturer literature shall be used, by the applicant, as a guide in preparing the project specific appendix to the maintenance agreement; however, the maintenance requirements shall be written to be specific to the project. When landscaping is a component of the stormwater management facility, a project specific maintenance schedule for the landscaping shall be provided that is reflective of the plant species that are used. The landscaping maintenance schedule shall contain guidance regarding methods, frequency, and time of year for landscape maintenance. The maintenance requirements shall stress the need to remove cut and remove vegetation from the BMP and the specific rate and method of fertilization, if any. A sample Maintenance Agreement is included on i ^ pe ff * ' ^ ^ .Roanoke County's website In addition, the applicant shall also establish easements for stormwater management facilities to grant the County the right of access for periodic inspections as described in Chapters 3 and 15. 14.3 Maintenance Program COUNTY OF ROANOKE 9 1 dx/1/16 14-2 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 A consistent maintenance program is the best way to ensure that stormwater management facilities will continue to perform their necessary functions. The following components are common to many stormwater management facilities maintenance programs and shall be followed, where applicable. • regular Inspections - Formatted: Underline Scheduled inspections and additional inspections after major storm events are necessary to understand the condition of the stormwater management facility and discover deficiencies so that they may be corrected. • Vegetation Mana eg ment _ _ _ _ _ _ _ _ _ _- Formatted: Underline Most stormwater management facilities rely on vegetation to filter sediment from stormwater and to stabilize the ground surface of the BMP. 0 blowing- - Formatted: Underline Some stormwater management facilities may have no mow zones. Do not mow areas meant to stay natural. If mowing is allowed and desired, most grasses are hardiest if maintained as an upland meadow, with a blade height of 6 to 8 inches. If a shorter lawn is desired, additional lawn care will be needed to maintain turf health. Never cut grasses below a blade height of 4 inches. Grasses on embankments should be cut at least twice in the spring growing season, once in the summer, and twice in the fall growing season. Grass clippings should be collected, removed from the BMP, and disposed of properly. Ideally grass clippings should be composted and used as fertilizer or mulch in an upland area. Grass clippings must never be dumped into streams, open channels, storm drains, ponds, or stormwater management facilities as they will release nutrients as they decay which will flow into streams. o Lertilization - Formatted: Underline One of the primary purposes of most stormwater management facilities is to remove nutrients from stormwater; therefore, it is important to not over fertilize. Often fertilization is not required, especially if grass is maintained at a height of 6 to 8 inches. Only fertilize where necessary to maintain the health of vegetation and then take care to apply only the minimum that is required. o Fest and Weed Control - Formatted: Underline Avoid unnecessary pesticide and herbicide use. When absolutely required, use pesticides and herbicides in accordance with listed instructions and never allow spray to enter water as many of these chemicals are toxic to aquatic life in small concentrations. COUNTY OF ROANOKE 9 U dx/1/16 14-3 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 ZZemoving Accumulated Sediment - - Formatted: Underline Vegetation surrounding stormwater management facilities is designed to trap sediment; therefore, vegetation is likely to become laden with sediment and bare spots may emerge. Bare spots should be raked, backfilled if needed, and covered with top soil. Disturbed areas should be reseeded and mulched. Excess material should be removed and may be used as a mulch or soil supplement. If the soil becomes compacted, then aeration may be necessary. _Unwanted Vegetation - I Formatted: Underline Embankments must be kept clear of woody plants (trees and bushes) because their roots could cause seepage or slope failure. Consistent mowing should control any unwanted vegetation. • _Slope, Embankment and Outlet Stabilization - Formatted: Underline Stable slopes and embankments are necessary to ensure that erosion does not add to water quality problems and that embankments do not breach. Maintaining a health stand of grasses on slopes and embankments and preventing the grown of deep rooted (trees and shrubs) vegetation on embankment areas are important. Animal burrows can also cause deterioration to embankments. Animal burrows should be filled in as soon as they are discovered. In some cases animal control may be needed to avoid excessive burrows. Outlet structures are particularly vulnerable to undercutting and erosion. A small problem, if it is not corrected, may quickly result in the need to replace an entire structure. Consult a professional engineer if sink holes, cracking, wet areas around the outlet pipe, pipe displacement, or rusting of the pipe is observed. • pebris and Litter Control Formatted: Underline Regular debris and litter removal will reduce the chance of clogging outlet structures, prevent damage to vegetated areas, reduce mosquito breeding habitats, improve site appearance, and reduce conditions for excessive algae growth. • Mechanical Components - Formatted: Underline Some stormwater management facilities have mechanical components including valves, sluice gates, anti -vortex devices, fence gates, locks, and access hatches that require periodic maintenance. • jnsect Control - Formatted: Underline The simplest way to control insects, particularly mosquitoes, is to avoid stagnant water. Most stormwater management facilities are designed to be dry within a short time after a rain event. If an insect problem develops in a detention basin or infiltration facility, then there is a maintenance issue that needs to be corrected. In stormwater management facilities, such as retention basins, that are designed to COUNTY OF ROANOKE 9 U dx/1/16 14-4 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 have a permanent pool of water insects may be controlled by the prompt removal of floatable debris and perhaps by introducing and maintaining a fish population. • Access Road and Area Maintenance - Formatted: Underline Most stormwater management facilities are designed to be accessible by heavy machinery for maintenance and repairs. Access should be maintained by periodic removal of woody vegetation and upkeep of gravel areas. • Sediment and Pollutant Removal - Formatted: Underline The primary purpose of many stormwater management facilities is the removal of sediments and nutrients (which are often attached to sediments). Sediment will naturally accumulate in a stormwater management facilities and must be periodically removed. The frequency of sediment removal will vary widely depending on the stormwater management facility's type and character of the contributing watershed. Removed sediments and pollutants should be properly disposed of in an upland area. They should be stabilized with vegetation so that they are not eroded by rainfall. Once sediment is removed, the stormwater management facility should be quickly restabilized, usually with vegetation. If maintenance operations disturb more than 5,000 square feet, an erosion and sediment control permit will be required before commencing work. Sediment and pollutant removal will usually take heavy equipment and is beyond the capabilities of most property owners without the assistance of appropriate contractors. • Component Repair or Replacement --------------------------------- t Formatted: Underline J Eventually, like all infrastructure, stormwater management facilities' components will need to be repaired or replaced. Components may include inflow and outflow devices, trash racks and anti -vortex devices, valves, orifices, pipes, concrete structures, filter or infiltration media, earthworks such as embankments and side slopes Following completion of construction, routine maintenance shall be performed on stormwater management facilities as required and as specified in the Maintenance Agreement. If the County becomes aware that a stormwater management facility has not been adequately maintained, is not functioning properly, or has becomes a danger to public safety, public health, or the environment, the responsible party will be notified in writing. The responsible party shall then be required to address the deficiency issue within a reasonable time as identified in the written notice. Failure to address the deficiency issue may result in enforcement actions. COUNTY OF ROANOKE 9 1 dx/1/16 14-5 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 14.3.1 Earthen Embankments Earthen embankments are an integral part of many BMPs including detention and retention basins and constructed wetlands. —For Earthen Embankments maintenance guidance, see Table 14.1. Table 14.1 Earthen Embankments Maintenance Required Action Maintenance Obiective Frequency of Action Inspections Inspect earthen embankments for signs of settlement, Annually seepage, woody vegetation growth, animal burrows, and good ground cover. Vegetation Management Objective is to maintain a healthy grass cover free of Mow grass on embankments at least trees and brush • Mow grass on embankments to a height of 6 to 8 twice during both growing seasons and inches. • Remove all trees and brush from embankment and once during the summer. at least 25' beyond embankment. When removing trees and brush, extract as much of the root as possible. • Fertilize, lime, or treat with pesticide or herbicide when needed to maintain grass health (do not over fertilize). • Reseed embankments as necessary to maintain vegetation. • Avoid over -fertilization. Slope, Embankment, • Fill animal burrows with compacted fill. . Regrade, repair, and revegetate eroded embankments. • If there are signs of seepage or embankment As needed based on and Outlet Stabilization damage observed during routine maintenance or inspections slumps consult with a professional engineer. Debris and Litter Control Keep the embankment clear of debris and litter During inspections or mowing Mechanical Com onents Not applicable Not applicable Insect Control Not applicable Not applicable Access Road and Area Maintenance Remove woody plants and maintain surface in drivable Annually condition Sediment and Pollutant Removal Not applicable Not applicable COUNTY OF ROANOKE q U XI1/16- 14-6 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 Component Repair Replace embankments that have major erosion, seepage, Infrequent and Replacement or slumping problems. Consult with a professional engineer. 14.3.2 Principal Spillways - - Formatted: Outline numbered + Level: 2 + Numbering Style: 1, 2, 3, ... + Start at: 3 + Alignment: Left + Aligned at: 0.25" + Tab after: 0.75" + Indent at: 0.75" Formatted: Indent: Left: 0.94", No bullets or numbering r Formatted: Indent: Left: 0", Hanging: 0.5", Tab stops: 0.5", List tab + Not at 0" Principal Spillways are an integral part of many BMPs including detention and retention basins Formatted: Indent: Left: 0.5", No bullets or numbering and constructed wetlands. Principal spillways normally consist of an outlet structure, pipe through an embankment, and outlet discharging to a downstream open channel. For guidance for the maintenance of Principal Spillways, see Table 14.2. Table 14.2 Principal Spillways Maintenance Required Action Maintenance Obiective Frequencv of Action Inspections Inspect outlet structure for signs of cracks, spalling, Semiannually and after broken or loose sections, or leakage, and corrosion or every major storm event damage to anti -vortex device or trash rack; inspect pipe inspect the outlet structure, pipe, and outlet protection. for signs of corrosion or settling: inspect outlet protection for signs of erosion or damage. Vegetation Management Not applicable Not applicable Slope, Embankment, Repair any erosion damage to outlet protection. As needed based on damage observed during and Outlet Stabilization routine inspections Debris and Litter Control Keep outlet structure clear of debris. Remove debris Semiannually and after from the BMP and properly dispose of in an upland area. major rain events as a minimum. Debris removal may be more frequent. Mechanical Components If a drain valve is present, exercise the valve semiannually to insure proper function. Periodically As noted lubricate the stem and paint exposed metal to protect from corrosion. Insect Control Not applicable Not applicable Access Road and Area Maintenance Remove woody plants and maintain surface in drivable Annually condition Sediment and Pollutant Removal Not applicable Not applicable Component Repair Repair or replace outlet structure components to correct Infrequently and Replacement leakage, cracks, spalling, broken or loose sections, or corrosion. Repair or replace pipe to correct settlement, leakage, or corrosion. Repair or replace outlet protection COUNTY OF ROANOKE q U XI1116 14-7 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 to correct erosion damage. Take care to avoid changing the BMP discharge characteristics and to avoid damage to the embankment. Repairs and replacements may require consulting a professional engineer. 14.3.3 Emergency Spillway Emergencv SDillways are an integral Dart of manv BMPs including detention and retention basins and constructed wetlands. Emergency spillways normally consist of an open channel, usually trapezoidal in cross-section, which are constructed beside an embankment to carry stormwater discharge from the BMP that is too great to be carried by the principal spillway. Emergency spillways should only discharge stormwater very infrequently Emergency spillways are most often vegetated (grassed), but may be protected against erosion by rip rap or concrete. For Emergency Spillways maintenance guidance, see Table 14.3. Table 14.3 Spillway Maintenance Required Action Maintenance Objective Frequency of Action Inspections Annually, and after any rain event that results in flow through the emer enc sillwa . Vegetation Management For a vegetated spillway the objective is to maintain a Mow grass at least twice during both growing seasons and healthy grass cover free of trees and brush • Mow grass to a height of 6 to 8 inches. • Remove all trees and brush from spillway. When once during the summer. removing trees and brush, extract as much of the root as possible. • Fertilize, lime, or treat with pesticide or herbicide when needed to maintain grass health (do not over fertilize). • Reseed spillway as necessary to maintain vegetation. Avoid over -fertilization. Slope, Embankment, Repair any damage to outlet. As needed based on damage observed during and Outlet Stabilization routine inspections Debris and Litter Control Keep the emergency spillway clear of debris and litter. During inspections or mowing Mechanical Components Not applicable Not applicable. Insect Control Not applicable Not applicable Access Road and Remove woody plants and maintain surface in drivable Annually COUNTY OF ROANOKE q U dx/1116- 14-8 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 Area Maintenance condition Frequency of Action Sediment and Pollutant Removal Not applicable Not applicable Component Repair Repair slopes and protective linings as needed. Infrequently and Replacement Slope, Embankment, 14.3.4 Sediment Forebav A sediment forebav is used as a pretreatment device to allow sediment to settle from the incoming stormwater runoff before it enters the balance of the BMP. A sediment forebav helps to isolate the sediment deposition in an accessible area, which facilitates BMP maintenance. For Sediment Forebav maintenance guidance, see Table 14.4. Table 14.4 Sediment Forebay Maintenance — - - Formatted: Indent: First line: 0" Required Action Maintenance Objective Frequency of Action Ins ections Observe del2th of sediment deposition Annually Vegetation Management Not applicable Not applicable Slope, Embankment, Not applicable Not applicable and Outlet Stabilization Debris and Litter Control Remove debris and litter that accumulates in the During inspections or sediment forebav as needed intermittently Mechanical Com onents Not applicable Not applicable Insect Control Not applicable Not applicable Access Road and Area Maintenance Remove woody plants and maintain surface in Annually drivable condition Sediment and Pollutant Removal Remove accumulated sediment. Dispose of Generally every 3 — 5 sediments in an upland area and stabilize with years or when 6 —12 vegetation. If necessary, obtain erosion and inches of sediment has accumulated. sediment control permit, prior to performing land disturbance. Component Repair Not applicable Not applicable and Replacement COUNTY OF ROANOKE q 1 X11116 14-9 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 14.3.5 Landscaping Landscaping is an integral part of many BMP's. It is important that the landscaping thrive in order for it to fully function for pollutant uptake and ground stabilization. For Landscaping maintenance guidance, see Table 14.5. Table 14.5 Landscaping Maintenance .- - - Formatted: Indent: First line: 0" Required Action Maintenance Objective Frequency of Action Inspections Observe landscaping growing conditions. If Monthly during the first landscaping is not thriving, correct conditions byrg owing season. Annually, in the fall, applying fertilization, pesticide, herbicide, or soil amendment. thereafter. Vegetation Management Each site shall have a site specific landscape Varies. Different plant maintenance schedule, depending on the species communities will require different levels used, that includes guidance regarding methods, frequency, and time of year for landscape of maintenance. maintenance and fertilization. Slope, Embankment, Not applicable Not applicable and Outlet Stabilization Debris and Litter Control Remove debris and litter. During inspections or as needed intermittently during vegetation management. Mechanical Components Not applicable Not applicable Insect Control Not applicable Not applicable Access Road and Area Maintenance Not applicable Not applicable Sediment and Pollutant Removal Not applicable Not applicable Component Repair Provide reinforcement planting after the first As needed based on observation during ins ections and Replacementrg owing season, if necessary. Thereafter, re lace caping that dies or fails to thrive. COUNTY OF ROANOKE q 1 X11/16 14-10 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 14.3.6 Stormwater Detention and Retention Basins For the design of basins v,._qtffifA4�-a' see GhE *e- 9. F,._ *he deli +i �. .- - - Formatted: Indent: First line: 0" fRr- 1 *,.,.M,A"A*Rr Ei alit , r*ra' Gr ,...t,.. ".see VA BMP Clearinghouse specifications. For maintenance guidance of stormwater basins, refer to the maintenance guidance for Earthen - - Formatted: Indent: First line: 0" Embankments, Principal Spillways, Emergency Spillways, Sediment Forebay, and Landscaping contained in this chapter. For additional maintenance guidance for basins, see Table 14.6. Table 14.6 Basins Maintenance (i) Required Action Maintenance Obiective Frequency of Action Ins ections Vegetation Management Slope, Embankment, and Outlet Stabilization Debris and Litter Control Keep the embankment clear of debris During inspections or mowing and litter Mechanical Com onents Insect Control Access Road and Area Maintenance Sediment and Pollutant Removal (1), also remove accumulated sediment (1), Depending on the effectiveness of the sediment from basin area. Dispose of sediments in an upland area and stabilize with forebay and the condition of the vegetation. If necessary, obtain erosion watershed, sediment removal and sediment control permit, prior to from the basin may be required performing land disturbance. every 5 — 10 years. Component Repair and Replacement (1) Refer to the maintenance guidelines for Earthen Embankments, Principal Spillways, Emergency Spillways, Sediment Forebay, and Landscaping contained in this chapter. COUNTY OF ROANOKE q 1 X11/16 14-11 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 14.3.7 Constructed Wetlands For use of constructed wetlands as a BMP, see VA BMP Clearinghouse specifications. see .- - - Formatted: indent: First line: 0" rte. For constructed wetlands maintenance guidance, refer to the maintenance guidance for Earthen Embankments, Principal Spillways, Emergency Spillways, Sediment Forebay, and Landscaping contained in this chapter. For additional maintenance guidance for constructed wetlands, see Table 14.7. - - Formatted: indent: First line: 0" Table 14.7 Constructed Wetlands(') Required Action Maintenance Obiective Frequency of Action Inspections (1), Document plant species distribution (1), Inspect at least semiannually for the first 3 - and fatality rates and verify compliance with landscaping reequirements;ey document sediment accumulations, ars" water elevations, and condition of the outlet. Ve etg ation Management Slope, Embankment, and Outlet Stabilization Debris and Litter Control Keep the embankment clear of debris During inspections or as needed and litter intermittently Mechanical Com onents Insect Control Li I U) Access Road and Area Maintenance Sediment and Pollutant Removal (1), As necessary, remove accumulated (1), Depending on the effectiveness of the sediment sediment from constructed wetland area and re-establish vegetation. Dispose of forebay and the condition of the sediments in an upland area and stabilize with vegetation. If necessary, watershed, sediment removal from the constructed wetland obtain erosion and sediment control may be required infrequently permit, prior to performing land disturbance. (every 10 years or less frequent . Component Repair and Replacement (1) Refer to the maintenance guidelines for Earthen Embankments, Principal Spillways, Emergency Spillways, Sediment Forebay, and Landscaping contained in this chapter. COUNTY OF ROANOKE q U XI1/16 14-12 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 14.3.8 Infiltration Practices For the design of infiltration basins and infiltration trenches as BMPs see VA BMP Clearinghouse specifications.Far ...,.,..i,..,ater- Ei ,.r e 94"tei: 11 of t4is r, 14.3.8.1 Infiltration Basin For Infiltration Basin maintenance guidance, refer to the maintenance guidance for Earthen .- - - Formatted: indent: First line: 0" Embankments, Principal Spillways, Emergency Spillways, Sediment Forebay, and Landscaping contained in this chapter. For additional maintenance guidance for infiltration basins, see Table 14.8A. Table 14.8A Infiltration Basin Maintenance (r) Required Action Maintenance Obiective Frequency of Action Inspections (1), Inspect basin to ensure that the basin (1), Monthly for the first 6 - functions as designed. Examine infiltration months: and thereafter semiannually and after major basin and outlet for clogging. Inspect for erosion, slumping, excessive sedimentation rain events. levels and vegetation overgrowth. Vegetation Management Slope, Embankment, and Outlet Stabilization Debris and Litter Control Keep the buffer area clean to reduce litter and During inspections or mowing floatables minimizing the clogging of the infiltration basin. Mechanical Components Ensure no standing water remains in basin Repair as needed based on after storm events. Standing water indicates observation during semiannual inspection. infiltration is clogged. Insect Control Remove accumulated sediment in basin and Remove sediment accumulation every 2 years or restore filtration area. If standing water is present during dry weather, the infiltration when infiltration basin has basin has become clogged. standing water. Access Road and Area Maintenance Sediment and Pollutant Sediment shall be removed and disposed in an Depending on the effectiveness of the sediment Removal upland area and stabilized with vegetation when sediment fills the sediment reserve forebay and the condition of capacity, or when the basin loses its infiltration capacity. If necessary, obtain the watershed, sediment removal may be required erosion and sediment control permit, prior to infrequently (every 10 years performing land disturbance. Avoid compacting the floor of the infiltration basin. or less frequent). Component Repair and Replacement (1) Refer to the maintenance guidelines for Earthen Embankments, Principal Spillways, Emergency Spillways, Sediment Forebay, and Landscaping contained in this chapter. COUNTY OF ROANOKE q U XI1116- 14-13 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 14.3.8.2 Infiltration Trench For maintenance requirements of infiltration trenches, see Table 14.813. Table 14.8B Infiltration Trench Maintenance Required Action Maintenance Objective Frequency of Action Inspections Inspect infiltration trenches to ensure that the Quarterly inspection BMP continues to function as initially for the first year, and intended. Examine for clogging of infiltration semiannual inspection trench. Document depth of water in observation well or assessable pretreatment thereafter device to assess dewater capacity of the facili . Ve etg ation Mana eg ment Buffer strips shall be mowed to 4 to 6 inches Cut grass twice during to limit unwanted vegetation. Trees shall be pruned such that the drip line both growing seasons and once during the summer. Prune overhanging trees annuall . does not extend over the surface trench. All trees shall be removed within the trench to prevent the puncture of filter fabric. Slope, Embankment, Regrade, repair, and revegetate eroded and As needed based on and Outlet Stabilization slumped buffer strips. damage observed during inspections. Debris and Litter Control Keep the buffer area clean to reduce litter and During inspections or floatables minimizing the clogging of the mowing infiltration trench. Mechanical Components Not applicable. Not applicable Insect Control Not anplicable Not agplicable Access Road and Area Maintenance Remove woody plants and maintain surface in Annually drivable condition Sediment and Pollutant Removal Remove accumulated sediment in infiltration Every 2 years or when trench and restore filtration area. sediment causes infiltration trench to have standing water. Component Repair Remove and replace top 6"-12" gravel and As needed based on and Replacement filter cloth sediment barrier. observation during inspections. COUNTY OF ROANOKE q 1 dx/1/16 14-14 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 14.3.8.3 Porous Pavement For the design of porous pavement as a BMP see VA BMP Clearinghouse specifications.- ;: 4,.4.m.,.,,.*4r a':l, e gliai3le-r- 11. For maintenance requirements of porous pavement, see Table 14.8.C. Table 14.8.0 Porous Pavement Maintenance Required Action Maintenance Objective Frequency of Action Inspections Inspect pavement to ensure proper Quarterly, and after every structural operation, and that the permeable aspect of the pavement has major rain events, until performance characteristics of not become clogged with debris. Measure water depth in storage laver the structure has been verified; thereafter, annually Ve etg ation Management Not applicable Not applicable Slope, Embankment, Not applicable Not applicable and Outlet Stabilization Debris and Litter Control Vacuum clean pavement surface, Monthly followed by high pressure water washing. Do not use sand or other abrasives during winter weather as they will clog the surface. Mechanical Com onents Not applicable Not applicable Insect Control Not applicable Not applicable Access Road and Area Maintenance Not applicable Not applicable Sediment and Pollutant Removal Not applicable Not applicable Component Repair No repair is possible. If pavement Depends on frequency and and Replacement becomes clogged, complete replacement thoroughness of pavement is required. cleaning COUNTY OF ROANOKE q 1 X11/16 14-15 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 14.3.9 Bioretention Filter See VA BMP Clearinghouse specifications Pfor the design of bioretention filters as BMPs. r Eioa . see moi. to �For maintenance guidance for bioretention filters, see Table 14.9. Table 14.9 Bioretention Filter Maintenance Required Action Maintenance Objective Frequency of Action Inspections Inspect filter to ensure that it continues Semiannually to function as initially intended. Observe sedimentation, standing water, and vegetation. Vegetation Management Provide adequate fertilization, pruning, Varies depending on plant species and other care for landscaping. Slope, Embankment, and Not applicable Not applicable Outlet Stabilization Debris and Litter Remove debris and litter. During inspections Control Mechanical Com onents Not applicable Not applicable Insect Control Not applicable Not applicable Access Road and Not applicable Not applicable Area Maintenance Sediment and Pollutant Removal Remove accumulated sediments and Annually dispose of them in an upland location and stabilize with vegetation. Component Repair Replace mulch laver. On an as needed Every 2 for routine mulch and Replacement basis replace the planting soil and ,years replacement. Every 5 years for vegetation to restore infiltration ca aci to the underdrain. plantingsoil oil replacement. COUNTY OF ROANOKE q 1 X11/16 14-16 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 14.3.10 Sand Filters See VA BMP Clearinghouse specifications for the design of sand filters. For maintenance .- - - Formatted: indent: First line: 0" guidance for sand filters, see Table 14.10. Table 14.10 Sand Filter Maintenance Required Action Maintenance Objective Frequency of Action Inspections Monitor and document water level in filter Quarterly and after each chamber and rate of dewatering after storm mai or rain event for the events. first year, semiannually and after each major rain event thereafter. Ve etg ation Management Not applicable Not applicable Slope, Embankment, Not applicable Not applicable and Outlet Stabilization Debris and Litter Control Not applicable Not applicable Mechanical Components Not applicable Note applicable Insect Control Nota licable Not licable Access Road and Area Maintenance Remove woody plants and maintain surface Annually in drivable condition Sediment and Pollutant Removal Pump out sedimentation chamber. If water Semiannually (midway has an oil skim, it should be removed by a between semiannual inspection events) firm specializing in oil recovery and recycling. Remove sediments and dispose of them properly in an appropriate landfill. Refill the first chamber with water to restore the water seal. Component Repair Remove and replace filter cloth and ballast Varies depending on the and Replacement gravel to restore filtering capacity when efficiency of the pretreatment device filter will no longer draw down within 40- hours. COUNTY OF ROANOKE q 1 X11/16 14-17 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 14.3.11 Grassed Swale See VA BMP Clearinghouse specifications for use of grassed swales as a BMP. Forrad ssed t- - - Formatted: indent: First dine: o" swale maintenance guidance, see Table 14.11. Table 14.11 Grassed Swale Maintenance Required Action Maintenance Obiective Frequency of Action Inspections Check for uniformity of vegetative cover or for • Weekly, until vegetation is established. • Thereafter, semi- annually. • In addition, inspect grassed swale for damage after mai or rain structural repair needed for concrete linings. Check for sediment and debris accumulation and for erosion problems or bank sloughing. events. Vegetation Management Objective is to maintain a healthy uniform Mow grass periodically. vegetative growth: Use proper mowing techniques. • Mow grass to a height of 6 inches. • Collect and remove grass clippings. • Periodic weeding of invasive species and Reseed as necessary. weeds. • Fertilize or treat with pesticide or herbicide when needed to maintain plant health (do not over fertilize). • Reseed and mulch any bare areas. Slope, Embankment, Regrade, repair, and revegetate eroded and As needed based on damage and Outlet Stabilization slumped areas. Repair channel lining, outlet observed. protection and rip rap where required. Debris and Litter Control Keep the channel clean to reduce litter and During inspections or moWing floatables being washed downstream. Mechanical Components Not applicable Not applicable Insect Control Not applicable Not applicable Access Road and Area Maintenance Not applicable Not applicable Sediment and Pollutant Removal Remove accumulated sediment in channels, Depends on site conditions behind check dams, and at outfalls and culverts to perform annually at a minimum. maintain flow capacity and drainage. Repair any damage that occurs during sediment removal. Component Repair Repair or replace check dams to maintain Annually or as needed and Replacement temporary ponding and to maintain filtered flow through check dams. COUNTY OF ROANOKE q U XI1116 14-18 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 14.3.12 Vegetated Filter Strip See VA BMP Clearinghouse specifications for use of vegetated filter strips as a BMP. For vegetated filter strip maintenance requirements, see Table 14.12. Table 14.12 Vegetated Filter Strip Required Action Maintenance Obiective Freguencv of Action Inspections Check the vegetation for uniformity of • Weekly, until vegetation is cover, sediment and debris accumulation, established. • Thereafter, semi-annually. and erosion. Check for proper operation of level spreader, if present. • In addition, inspect filter strip for damage after major rain events. Vegetation Management Obiective is to maintain a healthy uniform As dictated by conditions+ vegetativerg owth: • If the area is maintained as lawn use proper mowing techniques. Collect and remove grass clippings. • Periodic weeding of invasive species and weeds. • Periodic pruning of woody vegetation to stimulate grown. • Fertilize, lime, or treat with pesticide or herbicide when needed to maintain plant health (do not over fertilize). Slope, Embankment, Regrade, repair, and revegetate eroded As needed based on damage and Outlet Stabilization ground surface. observed during inspection Debris and Litter Control Keep the vegetated strip clean to reduce During inspections or mowing litter and floatables being washed downstream. Mechanical Components Not Applicable. Not Applicable. Insect Control Not Applicable. Not Applicable Access Road and Area Not Applicable. Not Applicable Maintenance Sediment and Pollutant Remove accumulated sediment and reestablish vigorous vegetation cover. Depends on site conditions Removal perform annually at a minimum. Dispose of sediments in an upland area and stabilize with vegetation. If necessary, obtain erosion and sediment control permit, prior to performing land disturbance. Component Repair and If level spreader is used, replace rigid lip Infrequently Replacement when necessary. COUNTY OF ROANOKE q U XI1116 14-19 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 14.3.13 Manufactured BMP Systems Several manufacturers have developed filter and screening devices which areag ining t- - - Formatted: indent: First gine: o" acceptability from the regulators as suitable BMPs for meeting stormwater quality requirements. These devices filter debris and sediment and other pollutants, such as metals and hydrocarbons from stormwater. Specific maintenance requirements for manufactured BMPs shall be in accordance with the - - Formatted: indent: First line: o" manufacturer's specifications and warranty requirements. rovide the Manufacturer's , - Formatted: Font: sold, underline specified guidelines for maintenance activities. See Table 14.13 for general maintenance guidance. Table 14.13 Manufactured BMP Maintenance Required Action Maintenance Objective Frequency of Action Inspections Inspect structure and inlets and outlets Semiannual or as specified by to ensure structural integrity and proper the manufacturer. functioning o1 the facility. Ve etg ation Management Not applicable Not applicable Slope, Embankment, Not applicable Not applicable and Outlet Stabilization Debris and Litter Control Remove debris and litter that interferes As needed based on impacts with proper operation. observed during semiannual ins ection. Mechanical Components Provide routine maintenance to valves, Per manufacturer's instructions. sluicegates, pumps or other mechanical devices per manufacturer's instructions. Insect Control Nota licable Not agplicable Access Road and Area Maintenance Not applicable Not applicable Sediment and Pollutant Removal Clean manufactured screen or filter Annually or as required. vault of debris, litter and floatable materials. Remove any sediment and ollutant build -M2 from the vault. Component Repair Repair or replace tank or vault structure As recommended by the manufacturer and as needed. and Replacement if leaks or cracks develop. Replace filtering media when necessary for proper functioning. COUNTY OF ROANOKE q 1 X11/16 14-20 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 14.3.14 Conservation Areas Conservation areas are naturally vegetated areas used to provide a measure of stormwater quality Formatted: Indent: First line: o" control as open space or forested areas. Conservation Areas should be maintained in their natural condition or can be planted to meet the VA BMP Clearinghouse specifications. Conservation areas reauire an easement. For Conservation Areas maintenance guidance, see Table 14.14. Table 14.14 Conservation Areas Maintenance Required Action Maintenance Obiective Frequencv of Action Inspections Check the vegetation for uniformity of cover . Quarterly, until vegetation and growth, sediment and debris accumulation, and erosion. is established. • Thereafter, annually. • In addition, inspect area for damage after maior storm events. Vegetation Management 1 Weed control to promote survival and If establishing new vegetation, rapid growth of trees and shrubs. continuous over first two years until vegetation is established. Vegetation shall be undisturbed after it has become established. Slope, Embankment, (z) Regrade, repair, and revegetate eroded As needed, based on damage and Outlet Stabilization and slumped banks. observed during inspections. Debris and Litter Control Keep the area clean to reduce litter and Annually, and after major storm events, clean debris and floatables being washed downstream. litter which has accumulated. Mechanical Components Not Applicable Not applicable Insect Control Normally not applicable. Normally not applicable. Access Road and Area Normally not applicable. Normally not applicable. Maintenance Sediment and Pollutant Normally not applicable. If heavy accumulations of sediment occur, then either Infrequent Removal remove sediment accumulation or stabilize sediment accumulation in place with top soil and additional vegetation plantings. Component Repair and Normally not applicable. If major areas lose Rare Replacement trees due to fire, disease, or other cause, then replanting may be needed. Note that most herbicides are very toxic to aquatic organisms. Follow listed instructions and never allow spray to enter waterways. (2) If maintenance work is required along the banks of jurisdictional streams or in wetlands, a permit may be required from the U.S. Army Corps of Engineers and the Virginia Department of Environmental Quality. COUNTY OF ROANOKE q U XI1116 14-21 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 14.3.15 Underground Detention Facilities Underground detention facilities are facilities that provide detention in underground pipes or chambers. For underground detention maintenance guidance, see Table 14.15. Table 14.15 Underground Detention Maintenance Required Action Maintenance Objective Frequency of Action Inspections Inspect condition of storage facility, outlet Semiannually structure, and presence of sediment and debris. Vegetation Management Not applicable Not applicable Slope, Embankment, Not applicable Not applicable and Outlet Stabilization Debris and Litter Control Remove debris and litter. As needed based on observations during semiannual inspection. Mechanical Com onents Not applicable Not applicable Insect Control Not applicable Not applicable Access Road and Area Maintenance Not applicable Not applicable Sediment and Pollutant Removal Remove accumulated sediments and Varies, depending on the dispose of them in an upland location and effectiveness of the pretreatment device. stabilize with vegetation. Component Repair Replace failed pipe, storage chambers, or Rare and Replacement other com onents. COUNTY OF ROANOKE q 1 X11/16 14-22 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES CHAPTER 14 14.4 Additional Maintenance and Repairs The routine maintenance items listed in the Maintenance Agreement are the minimum measures If actual conditions demonstrate that additional maintenance or repairs are necessary for proper functioning of the stormwater management systems, they shall be provided by the responsible party - 14.5 Inspection and Maintenance Records The responsible party or property owner shall maintain records of stormwater management facilities' inspections and maintenance activities, and submit copies to the County, when requested. 14.6 References The VA SWM Handbook and VA BMP Clearinghouse website 4a& -contain information on maintenance of all VA DEQ approved nonproprietary BMPs- r, Ai4#,.:r:r c. -+P . . S3,Ste+H n n_..:,7,.t�,.,.v sem,- v„ . A*8 OW -Refs a*d n.. C',.,- 41A ..r ............ ..C...iA'ate BN44-21; n4q.7 ♦7.:.. ,7,.,...m -eq* : ,.1..,7,.,7 4 n....,...,7:., 1 4B COUNTY OF ROANOKE 9 U XI1/16 14-23 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES APPENDIX 14A APPENDIX 14A MAINTENANCE AGREEMENTS Stormwater Management/BMP Facilities — Sample Maintenance Agreement can be found at http://Www.roanokecomtyva.gov/index.aspx?NID-331 Maintenance Agreements shall be submitted to: Department of Community Development Roanoke County Administration Center 5204 Bernard Drive P.O. Box 29800 Roanoke, VA 24018-0798 Procedures for submitting agreements: • Type all information on the agreement form. • Authorized property owner must sign form in black ink. • Signature must be properly notarized lack IiD. • Attach a check for the recordation fee. • The Department of Community Development will coordinate the County Attorney and County Executive signatures, and recordation. • Maintenance agreements are required to be submitted, approved, and executed prior to the pre -construction meeting. COUNTY OF ROANOKE 9 /�/t dx/1/16 14A-1 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES APPENDIX 14A A444 l.RA 140f@i+f.#,.4. ,...110,1 ♦1.,. AN R A C 448 T ....,1,.11 .. ♦1.,. ,. 14 F,.,... „10 ,.F e eft,.:.. ,,.,.1 ,. ,.,.r., ,1,...,.,.:1.04 Off aS f8effElOd 1.., ,1804 4 440 1..44,1 , ,.,.,1.. „F -,.....RkR G -.IM#)', 3AF`qi+l:�1..4,..,.1.,...�T 1.�.1.RW. ,.:....A�. ,...11,.,1 R.,. "D,.,,„,,,.r., ” 3A7uL`RVL 48 -cr�cC too Site �j1,1�:1.:�yl k44RW...S 37< U] UL' 48, 440 D,.,,„,,,•r., ..r..:......rOf „r F..,1:1:ti Rq COUNTY OF ROANOKE 74V -1-4x/1/16- 14A-2 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES APPENDIX 14A COUNTY OF ROANOKE ;444X/1/16- 14A-3 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES APPENDIX 14A COUNTY OF ROANOKE ;444X/1/16- 14A-4 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES APPENDIX 14A COUNTY OF ROANOKE 14x/1/16 14A-5 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES APPENDIX 14A COUNTY OF ROANOKE 14x/1/16 14A-6 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES APPENDIX 14A COUNTY OF ROANOKE 14x/1/16 14A-7 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES APPENDIX 14A .- - - j Formatted: Left COUNTY OF ROANOKE 14x/1/16 14A-8 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES APPENDIX 14A c00 *hR c*RVMFA, tof Nfafi.,.,.. oq* - ,nwii:. n , R. F fogoifements at .- - - Formatted: Centered COUNTY OF ROANOKE 9/1-1 dx/1/1(r 14A-9 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES APPENDIX 14A Right �P,hgd.lal@ .- - - Formatted: Centered AVOR COUNTY OFROANOKE 9 U dx/1/1(r 14A-10 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES APPENDIX 14A .- - - Formatted: Centered, Indent: Hanging: 0.5, Tab stops: t 0.38", Left + 0.75', Left + 3.25', Centered Formatted: Centered website.) COUNTY OF ROANOKE 9 U dx/1/1(r 14A-11 MAINTENANCE MAINTENANCE OF STORMWATER MANAGEMENT FACILITIES APPENDIX 14B .- - - Formatted: Adjust space between Latin and Asian text, Adjust space between Asian text and numbers - - Formatted: Centered, Adjust space between Latin and Asian text, Adjust space between Asian text and numbers - - Formatted: Adjust space between Latin and Asian text, Adjust space between Asian text and numbers COUNTY OF ROANOKE ;444x/1/16 44914A-1 MAINTENANCE INSPECTION AND ENFORCEMENT CHAPTER 15 Chapter 15 - Inspection and Enforcement Inspection and enforcement can be divided into two distinct categories, construction and pest post -construction. Construction inspection ensures that the storm drainage systems and stormwater management facilities are constructed and installed in accordance with the approved Stormwater Management Plan. Once construction is complete, a final inspection will be conducted, and as -built documentation will be submitted to show that the constructed project meets the requirements of the approved Stormwater Management Plan. At this point, the responsibility for the operation and maintenance of the storm drainage systems and stormwater management facilities is transferred from the permittee to the property owner or responsible party. Where a project is constructed in phases, a final inspection shall be conducted of each completed phase as designated by the approved Stormwater Management Plan. The final inspection shall consist only of the phase being identified as complete. After construction is complete, the property owner or responsible party is required to conduct periodic inspections and maintenance of the stormwater management facilities. Property owner inspections and maintenance activities must be documented and maintained. The County of Roanoke will also conduct periodic post -construction compliance inspections of stormwater management facilities. 15.1 Construction Inspections Construction of storm drainage systems and stormwater management facilities shall comply with the approved final Stormwater Management Plan. Any changes to the approved design require a resubmittal to the County of Roanoke for approval. Inspections shall be performed by the permittee to ensure that construction conforms to the approved plans and specifications. Additional inspections will be performed by the County of Roanoke to confirm compliance. 15.1.1 Notifications to the County of Roanoke The permittee shall notify the County of Roanoke in advance of the start of construction and of the construction of critical components of a stormwater management facility. The following are examples of, but not limited to, critical components: • Before the start of construction; • Before installing a stormwater pond embankment; • Before installing pond outlet structures; COUNTY OF ROANOKE q444x/1/16 15-1 INSPECTION AND ENFORCEMENT INSPECTION AND ENFORCEMENT CHAPTER 15 • Before setting any concrete BMP structures, this does not include precast drop inlets or manholes; • Before installing energy dissipation structures and any outlet structure into a jurisdictional stream (perennial or intermittent flow); • Before installing any infiltration or bioretention BMP; or • Any other key BMP component as determined by the County of Roanoke 15.1.2 Periodic Inspections The permittee is responsible to perform adequate inspection of the construction activities to confirm that the site is in compliance with the Erosion and Sediment Control Ordinance requirements and that the construction of storm drainage systems and stormwater management facilities and BMPs are in conformance with the approved Stormwater Management Plan. Upon completion of construction, the permittee must provide certification from a licensed professional that the completed project is in accordance with the approved plans and specifications and must provide documentation of regular inspections sufficient to adequately support compliance. All permittee inspections shall be documented and written reports prepared that contain the following information: • The date and location of the permittee inspection; • Whether construction is in compliance with the approved Stormwater Management Plan; • Variations from the approved construction specifications; • Corrective actions that have been taken to correct previous violations; • Any violations that exist or corrective actions that have been completed; and • The name and signature of the person who performed the inspection. The County of Roanoke shall conduct periodic inspections during construction. During the County inspection, the permittee will provide all permittee inspections which have been conducted since the last County inspection for County observation. If the County finds any violations, the permittee shall be notified in writing of the nature of the violation and of the required corrective actions. In conjunction, the County may issue an order requiring that all or part of the land disturbing activities permitted on the site be stopped until the specified corrective measures have been taken. If the County of Roanoke determines that there is a repeated failure to comply with the approved plans and specifications, enforcement action may be taken. COUNTY OF ROANOKE q444x/1/16 15-2 INSPECTION AND ENFORCEMENT INSPECTION AND ENFORCEMENT CHAPTER 15 15.1.3 Final Inspection and As -Built Documentation Prior to final acceptance of the project the permittee is required to submit to the County of Roanoke as -built documentation, confirming that the storm drainage systems and stormwater management facilities and practices that have been constructed conform to the approved Stormwater Management Plan. In addition, once the as -built documentation has been submitted, a final inspection will be conducted by the County of Roanoke to confirm that the as -built documentation conforms to the actual construction. As -built documentation shall include the following: _General: - I Formatted: Font: Bold, Underline • As -built survey conducted following construction, ee#i4ied sealed by a —reg-istere4-Registered la*E�-Land *ufveyer Surveyor and/or pr-e€essiexal Professional eng-irfeerEn ingeer. As -built plans shall be a "redline" of the approved plans pr a record drawing (as outlined below_) and shall be to - Formatted: Highlight scale and provide a north arrow. Formatted: Highlight • Stormwater easements and access easements shall be shown on the plans with metes and bounds. • Certification statement, signed by the permitee and a Licensed Professional indicating conformance with the approved Stormwater Management Plan (including certification to both the storm drainage and stormwater BMPs are in compliance with the approved plans). • A supplemental digital file is required for County records and shall be provided via the FTP site or on a CD-ROM made available in an AutoCAD format shown with the laver configurations described in Section151.4.-------------- - - - - -- Formatted: Not Highlight The permittee's inspection log records with copies of all inspection test results documenting compliance with the approved Stormwater Management Plan. Storm Drain Systems: • All storm system structures identified and labeled the same as the approved plan. All structure elevations are to include an invert elevation, a top of grate (at grade) elevation and any opening elevations used for storm water intake numoses (NAVD 88). All data is to be verified to the closest hundredth of a foot (0.01 COUNTY OF ROANOKE q444x/1/16 15-3 INSPECTION AND ENFORCEMENT INSPECTION AND ENFORCEMENT CHAPTER 15 • All storm system pipes identified and labeled the same as the approved plan with upstream and downstream invert elevations (NAVD 88), the total length of the pipe run from end to end, with the calculated slope. All data is to be verified to the closest hundredth of a foot (0.01). • Maximum tolerances shall be based upon the following: 1. Does the structure function properly (i.e. is pipe capacity greater than the calculated flow, etc)? 2. Has the proper amount of cover been provided? 3. Has a minimum as -built slope of 0.40% been provided or O,g greater than 3 fps - , - Formatted: Subscript (whichever is more restrictive). • Redline revision of approved storm drainages profiles and horizontal - - - , - Formatted: Font: Bold, underline layout plans c*,....,,,.,,.*Rr r,r,.r ,.8+H8F* 121a for as -built storm drainages Structures. ni,.,.g A ,.i.,.,.v Mad- W401:0 desig .aloes agizee :*i ,.,.,,.,.i 444gietea .,aloes. For changed values, strike thru the design value and enter the constructed value, i4q 4:Rd.- A one page "record drawing". may be provided for the as-builts which , - Formatted: Highlight includes the following information as a minimum: 1. Storm drainage - - - Formatted: Font: Bold, underline, Highlight profiles or storm drainage table which shows structure number, rim, Formatted: Highlight inverts, pipe length, diameter, and slope: and 2. horizontal layout of storm- Formatted: Highlight drainage on plans (plan should also show the location of buildingseddge of \ ' Formatted: Highlight pavement, sidewalk, curb andutg ter, property line. etc). - - Formatted: List Paragraph, No bullets or numbering, Adjust • Label plan sheet as as -built. space between Latin and Asian text, Adjust space between Asian text and numbers, Tab stops: Not at 1.5" BMPs: • Redline of approved Stormwater Management Plan for BMWs_ For -------- Formatted: Font: Bold, underline changed values, strike thru the design value and enter the constructed value. Provide as -built dimensions of the structures, grades, slopes, elevations, BMP components details), etc on the plans to verify that the , - Formatted: Highlight structure has been constructed correctly. A one page record drawing may be provided for the as-builts which F - - Formatted: Indent: Left: 1.25" includes the following information as a minimum: 1. Horizontal layout of Formatted: Font: Bold, underline BMP on plans (plan should also show the location of buildings, edge of pavement, sidewalk, curb andutg ter, property line, etc), 2. As -built contours if required (i.e. bioretention), 3. Accessory structure details (i.e. berm, orifice, outlet structure, diaphragms, weirs, soil media, etc.). This should be provided with the BMP details on the as -built plan, , - Formatted: Highlight • Update the BMP table on the plans and label as "as -built". Provide latitude and longitude of as -built BMP. COUNTY OF ROANOKE q4U dx/1/16 15-4 INSPECTION AND ENFORCEMENT INSPECTION AND ENFORCEMENT CHAPTER 15 • Provide available Manufacturer certification that the structure was installed correctly. • Label plan sheet as as -built. • A supplemental digital file is required for County records and shall be provided via the FTP site or on a CD-ROM made available in an AutoCAD format shown with the laver configurations described in Section 15.1.4. Ditch and Channel Sections: • Provide ditch/channel cross-sections plotted to scale, 300 feet maximum intervals or portion thereof, minimum of 2 per ditch, with adequate spot elevations that defines the ditch section and slope as required by the approved plan. Label distances between spot elevations on the cross sections. The Engineer shall show the location on the swale where the cross section is being provided. • Cross sections are to be shown and labeled on the plan. • Maximum tolerances shall be based upon the following: 1. Does the structure function properly (i.e. is swale capacity greater than the calculated flow, etc)? 2. Has the proper amount of depth/freeboard been provided? 3. Has a minimum as -built slope of 2.0% been provided vegetated swales or 1.0% for riprap or concrete lined channels? 4. Has the maximum allowable velocitv for the channel linine been exceeded? • A supplemental digital file is required for County records and shall be provided via the FTP site or on a CD-ROM made available in an AutoCAD format shown with the laver configurations described in Section 15.1.4. Ponds: • Redline of approved Stormwater Management Plan for ponds. For _ - changed values, strike thru the design value and enter the constructed value. Provide as -built dimensions of the structures, pipe.sloves, berms. elevations, pond structure; omponents (details) etc on the plans to verify \ that the structure has been constructed correctly. • A one page "record drawing" may be provided for the as-builts which includes the following information as a minimum: 1. Horizontal layout of COUNTY OF ROANOKE q444x/1/16 15-5 INSPECTION AND ENFORCEMENT Formatted: Highlight Formatted: Highlight Formatted: Highlight Formatted: Highlight Formatted: Highlight Formatted: Highlight Formatted: Indent: Left: 1.5', No bullets or numbering INSPECTION AND ENFORCEMENT CHAPTER 15 pond on plans (plan should also show the location of buildings, edge of pavement, sidewalk, curb andutg ter, property line, etc), 2. As -built contours, 3. Accessory structure details (i.e. berm, orifice, outlet structure, weirs, etc.). This should be provided with the pond details on the as -built plan- 1___The survey shall include enough information to verify that storage capacities are no less than the storage volume required by the approved Stormwater Management Plan. For retention and detention structures, a stage -storage summary table with design values and as -built values shall be included. The survey shall verify inverts and sizes of pipes, culverts, and outlet structures. A4n*:m im *,.',.,.,.r,.,. 04—nil -e i1 n 1 F et F • Show location of and label elevations and width of berm. • Show location and label dimension and elevations of spillways. • Label Dlan sheet as as -built. • A supplemental digital file is required for County records and shall be provided via the FTP site or on a CD-ROM made available in an AutoCAD format shown with the layer configurations described in Section 15.1.4. If it is determined from the as -built documentation that the storm drainage systems afA or the stormwater management BMP facilities have not been constructed in accordance with the approved Stormwater Management Plan, then corrective action will be taken to comply with the approved Plan or the permittee shall provide studies and information required by the County of Roanoke to demonstrate that the constructed systems will function equivalent to the approved Stormwater Management Plan. This includes meeting all flow, velocity, and regulatory requirements and that the approved elevation -storage requirement is maintained. Once the as -built documentation has been accepted by the County of Roanoke, the permittee shall schedule a final inspection of the project site prior to final acceptance of the project by the County and the return of performance bonds or securities. The permittee shall provide 48 hour notice of a final inspection to the County of Roanoke. 15.1.4 ACAD Digital File Requirements COUNTY OF ROANOKE q444x/1/16 15-6 INSPECTION AND ENFORCEMENT INSPECTION AND ENFORCEMENT CHAPTER 15 The following items shall be submitted in ACAD format with the as-builts. All items shall be tied to the State Plane Coordinate and NAVD 88. All items shall be set to an elevation of zero, unless otherwise noted. • Storm drainage pipe and structures. Structures shall be shown at their as - built location. • Stormwater BMPs shown at the as -built location. BMPs shall be labeled to match the plans. Ponds, swales, infiltration basins, etc shall provide as - built contours and have applicable elevation assigned to the line work. • Proposed -Ttopographic contours inside the site property boundary for the approved proiect. These contours are the line work as shown on the approved plans and are not as -built contours, but line work from the CAD drawings. Elevations shall be assigned to the line work. • Easements and right-of-ways. • Property lot lines. • Edgeoff pavement. • Building layout. 15.2 Post -Construction Inspections and Maintenance The property owner or responsible party is responsible for the proper operation, inspection, maintenance, and repair of stormwater management facilities, after the completion of construction, in accordance with the applicable maintenance agreement. All inspection, maintenance, and repair activities shall be documented. The responsible party shall inspect and maintain stormwater management facilities at the frequencies listed in the Maintenance Agreement,, In addition to the inspections performed by the responsible party, each stormwater management facility will be inspected periodically by the County of Roanoke. In the event that the stormwater management facility has not been maintained and/or becomes a danger to public safety, public health, or the environment, the County of Roanoke shall notify the property owner, or responsible party, by registered or certified mail and issue a Notice of Violation. The Notice shall specify the measures needed to correct the situation and shall specify the time within which such measures must be completed. If the responsible party fails or refuses to meet the requirements of the maintenance agreement, the County of Roanoke, after reasonable notice, may apply a civil or criminal penalty and may correct a violation of the design standards or maintenance needs by performing all necessary work to place the facility in proper working condition, and recover the costs from the responsible party or property owner. 15.3 Records Parties responsible for the operation and maintenance of a stormwater management facility shall make records of the installation and of all inspections, maintenance and COUNTY OF ROANOKE q444x/1/16 15-7 INSPECTION AND ENFORCEMENT INSPECTION AND ENFORCEMENT CHAPTER 15 repairs, and shall retain the records for at least five (5) years. These records shall be made available to the County of Roanoke upon request. Examples of (inspection records can be found on the BMP Clearinghouse website, in Appendix 15A, or obtained from Manufacturer literature. 15.4 Enforcement Any activity that is commenced without an approved Stormwater Management Plan, or is conducted contrary to the approved Stormwater Management Plan, may be subject to the enforcement actions outlined in the County of Roanoke Stormwater Management Ordinance. A property owner or responsible party that does not properly maintain a stormwater management facility in accordance with the maintenance agreement may be subject to the enforcement actions outlined in the County of Roanoke Stormwater Management Ordinance. 15.4.1 Notice of Violation When a County of Roanoke inspection has noted that a construction activity or maintenance of a stormwater management facility is not in compliance with the approved Stormwater Management Plan, including all maintenance agreements, or the County of Roanoke Stormwater Management Ordinance, the County shall issue a written notice of violation delivered by registered or certified mail to the permittee or property owner. The notice of violation shall include: • The name and address of the responsible party; • The address when available or a description of the building, structure or land upon which the violation is occurring; • A statement specifying the nature of the violation; • A description of the remedial measures necessary to correct the violation and a time schedule for the completion of such remedial action; • A statement of the penalty or penalties that may be assessed against the person to whom the notice of violation is directed, should the remedial measures not be implemented; • A statement that the determination of violation may be appealed by filing a written notice of appeal within 30 days of service of notice of violation. COUNTY OF ROANOKE q444x/1/16 15-8 INSPECTION AND ENFORCEMENT INSPECTION AND ENFORCEMENT CHAPTER 15 15.4.2 Stop Work Orders If a project site is under construction and receives a notice of violation, construction activities in the area where the work was found to be deficient in meeting the approved Stormwater Management Plan shall cease immediately. The stop work order will be in effect until the County of Roanoke confirms that the land disturbing activity is in compliance with the approved Stormwater Management Plan. The permittee shall address the remedial measures published with the notice of violation within the time period specified. Upon completion of the remedial measures, the County of Roanoke shall inspect the work and authorize the permittee in writing that the stop work order has been removed and work may continue in that area of the project. Failure to comply with a stop work order or with a notice of violation may result in the revocation of the permit and the violator shall be subject to the penalties set forth by the Stormwater Management Ordinance. 15.4.3 Restoration of Lands Any violator may be required to restore land to its undisturbed condition in accordance with a notice of violation, stop work order, or permit requirements. In the event that restoration is not undertaken within the time specified in the notice, the County of Roanoke may take necessary corrective action, the cost of which shall be covered by the performance bond, or become a lien upon the property until paid, or both. COUNTY OF ROANOKE q444x/1/16 15-9 INSPECTION AND ENFORCEMENT INSPECTION AND ENFORCEMENT APPENDIX 15A APPENDIX 15A INSPECTION FORMS Stormwater Management Construction Inspection Checklist Stormwater Management Facilities Inspection Report Form Stormwater Management Facilities Maintenance/Repair Report Form COUNTY OF ROANOKE q444x/1/16 15A-1 INSPECTION AND ENFORCEMENT INSPECTION AND ENFORCEMENT APPENDIX 15A Stormwater Management Construction Inspection Checklist Inspector Name: Permittee's Name: Site Address or Location: Watershed: Reason for Inspection: ❑ Routine Inspection ❑ Complaint Disturbed Area (at time of inspection): Does the Site Require: ❑ Erosion and Sediment Control Plan Inspection Date: Permit Number: Tax Map or Parcel ID No: ❑ Intensive Rainfall ❑ Other ❑ Stormwater Pollution Prevention Plan ❑ SPCC Plan (oil storage) ❑ Other If required, are these plans or permits available on-site? Erosion and Sediment Control Item Used Acceptable Observations and Completion Condition Actions Required Date Silt Fence Y ❑ N ❑ Y ❑ N ❑ Straw Bales Y ❑ N ❑ Y ❑ N ❑ Inlet Protection Y ❑ N ❑ Y ❑ N ❑ Stabilized Construction Entrance Y ❑ N ❑ Y ❑ N ❑ Sediment Trap/Basin Y ❑ N ❑ Y ❑ N ❑ Check Dams Y ❑ N ❑ Y ❑ N ❑ Seeding (Temporary or Final) Y ❑ N ❑ Y ❑ N ❑ Other: Y ❑ N ❑ Y ❑ N ❑ Y❑ N❑ Y❑ N❑ Y 1 N 1 Y 1 N 1 Y 1 N 1 Y 1 N 1 Page 1 of 2 COUNTY OF ROANOKE q444x/1/16 15A-2 INSPECTION AND ENFORCEMENT INSPECTION AND ENFORCEMENT APPENDIX 15A G,._. .etaDiserepaneies afid Geffeetions Gefgletiea Date �n N �nN �n�rn �u rru Stormwater Collection and Transport (Culverts, Storm Drains, and Inlets) Item Constructed as Approved? Discrepancies and Corrections Completion Date Y❑ N❑ Y 1 N 1 Y 1 N 1 Y 1 N 1 Y 1 N 1 Y❑ N❑ Y 1 N 1 Y 1 N 1 Discharge Outfall from Development Adequate channel: Y❑ N❑ Signature of Inspector Page 2 of 2 COUNTY OF ROANOKE q444XI1/16 15A-3 INSPECTION AND ENFORCEMENT INSPECTION AND ENFORCEMENT APPENDIX 15A .- - - Formatted: Centered 1�effi lfispe4eed C-44gelced Do embam4aneats, spi4ways, side 3ivpos.. or i fflet� Outlet a ., � ���JJJ 44 � 4 Ttl RrR o..:,l 4w. , of animal vegeiation .. tt. gra that.. a toff «o with the flow a is thoFe a 1...:1d up of ..1:....:...,. inappropFiale arRas2 „Fl_..FF..f ..f,...,. ,. ,qll a4 P�aqiA.lq Fir with the propor oporatiF)44 f Is ,.F,.:1 ,. a4hof COUNTY OF ROANOKE 9 /,/t X/1/16 15A-4 INSPECTION AND ENFORCEMENT - Formatted: Centered Formatted: Centered Formatted: Centered Formatted: Centered Formatted: Centered Formatted: Centered Formatted: Centered Formatted: Centered Formatted: Centered Formatted: Centered Formatted: Centered Formatted: Centered Formatted: Centered Formatted: Centered Formatted: Centered Formatted: Centered Formatted: Centered Formatted: Centered Formatted: Centered - - Formatted: Centered FarmattM- Centereri Formatted: Centered INSPECTION AND ENFORCEMENT APPENDIX 15A Page 4-1 of -;k1 COUNTY OF ROANOKE q444XI1/16 15A-5 INSPECTION AND ENFORCEMENT Checked Maintenance Item Inspected Observations and Remarks Yes No Reqd. Not Req. Culverts and Storm Drains Is the culvert or storm drain filled more than 25% with debris, El 11 E] sediment, or trash? Is there evidence of structural El 11 11failure 11 of the culvert pipe? Is there evidence of erosion at the inlet and outlet of the culvert or at the storm drain inlet? Are there signs of settling, cracking, or misalignment of ❑ ❑ ❑ culverts, storm drain pipe, or concrete inlets? Stormwater Ponds (see also Embankments) Is the emergency spillway clear of obstructions, debris, and vegetation? Is the outlet structure and pipe clean of debris and sediment, free L1 0' L1 11 of damage, and in working order? Is there an accumulation of debris, ❑ litter or trash? (For dry detention ponds) Is there ❑ El 11standin water in the pond? (For wet ponds) Is their excessive 11 El 11 11algae growth or other vegetation' Is there evidence of oil or other ❑ ❑ ❑ ❑ pollutants in thepond? Is there erosion at the discharge ❑ ❑ point? Do any safety devices, fences, ❑ ❑I ❑ gates, or locks need repair? 04401. ur,rv., (1r4148tiR44 c,.44,l Lilt..,.. fia r,r,.+.,r „t,,,.,.,1 c.,..,,,.,,,., o is there se.l:,....e«t debislifter-, a .. ash 4iat.,lee.l.. t..�l.e reaseas? al al �e19 44 -4- 4 4 Are t4ere signs of e. -,...:,......t oan-cmco-orv.rrror Page 4-1 of -;k1 COUNTY OF ROANOKE q444XI1/16 15A-5 INSPECTION AND ENFORCEMENT INSPECTION AND ENFORCEMENT APPENDIX 15A STORMWATER MANAGEMENT BMP FACILITIES INSPECTION REPORT FORM Inspection Requirements: See the Stormwater Management BMP Facilities Maintenance Schedule for landowner's responsibilities for frequency of inspection and other requirements. This information is a part of the Maintenance Agreement that is recorded in the land records with the deed. Inspection Purpose: To assure safe and proper functioning of the stotmwater management BMP facilities and associated structures, by providing regular observations of their conditions and operation. Retention of Records: All inspection/maintenance/repair documentation shall be retained by the landowner for a minimum of five (5) years. Submission of Records: At the end of each year, by December 31 ', mail all BMP inspection and maintenance documentation to: County of Roanoke Department of Community Development 5204 Bernard Drive Roanoke, Virginia 24018 Attention: Stormwater Program Manager'&eFdi ate (BMP Inspection - - Formatted: Indent: First line: 0" and Maintenance Records) NAME OF BUSINESS OR LANDOWNER-- ADDRESS: ANDOWNER ADDRESS: INSPECTION DATE: PERFORMED BY: Facility Management Checklist The following items should be checked for each BMP: COUNTY OF ROANOKE q444x/1/16 15A-6 INSPECTION AND ENFORCEMENT INSPECTION AND ENFORCEMENT APPENDIX 15A 1. Facility construction meets the requirements of the Roanoke County Stormwater Management Design Manual, where applicable, and is adequate for the intended function. 2. The facility has been maintained properly according to the requirements of the Recorded Maintenance Agreement, BMP Maintenance Schedule, and the Roanoke County Stormwater Management Design Manual. 3. The facility is functioning adequately. 4. There have been no changes to the site conditions or area that would require modification and/or replacement of the existing facilities. 5. Access to the facility is adequate and maintained. Sheet 1 of COUNTY OF ROANOKE q444x/1/16 15A-7 INSPECTION AND ENFORCEMENT INSPECTION AND ENFORCEMENT APPENDIX 15A .- - - Formatted: Centered - - Formatted: Centered, Tab stops: -0.84", Left + -0.5", Left h + 0", Left + 0.38", Left + 0.5", Left + 0.75", Left + 1 v rr Left + 1.5", Left Formatted: Centered .a—.a - - Formatted: Centered, Indent: Left: 0", First line: 0", Tab stops: 0", Left + 0.5", Left + 1", Left + 1.5", Left rico^E}�Firetxcixr's-tor Met r,....ii3l:,.�,,,. Sheet of COUNTY OF ROANOKE q44444x/1/16 15A-8 INSPECTION AND ENFORCEMENT INSPECTION AND ENFORCEMENT APPENDIX 15A STORMWATER MANAGEMENT BMP FACILITIES MAINTENANCE/REPAIR REPORT FORM Maintenance Requirements:_ Refer to the site's Stormwater Management BMP Facilities Maintenance Schedule for landowner's responsibilities for frequency of maintenance and other requirements. This Maintenance Schedule is a guideline of minimum maintenance requirements. Additional maintenance shall be performed as necessary for the proper functioning of Stormwater Management BMP facilities. This information is a part of the Maintenance Agreement that is recorded in the land records with the deed Maintenance Purpose: To enable the proper long-term functioning of the stormwater management BMP facilities to protect the Valley's water quality and prevent downstream flooding. Retention of Records: All inspection/maintenance/repair documentation shall be retained for a minimum of five (5) years. Submission of Records: At the end of each year, by December 31 ', mail all BMP inspection and maintenance documentation to: County of Roanoke Department of Community Development 5204 Bernard Drive Roanoke, Virginia 24018 Attention: Dewe',.,.. en! 4 ev ewStormwater Program Manager Caa (BMP Inspection and Maintenance Records) NAME OF BUSINESS OR LANDOWNER: ADDRESS: MAINTENANCE/REPAIR DATE: PERFORMED BY: GENERAL COMMENTS: COUNTY OF ROANOKE q444x/1/16 15A-9 INSPECTION AND ENFORCEMENT INSPECTION AND ENFORCEMENT APPENDIX 15A Sheet 1 of COUNTY OF ROANOKE q444x/1/16 15A-10 INSPECTION AND ENFORCEMENT INSPECTION AND ENFORCEMENT APPENDIX 15A .- - - Formatted: Tab stops: Not at -0.84" + -0.5" + 0" + 0.5" REFER RECORDED THE; DCORDED Air A INT -`N A1� GE A!`REEAA ENT BAA U AiT A T1�TTL'1�T A 1�T!`L` + 1" + 1.5" ic1.Z - - Formatted: Centered, Tab stops: Not at 0" + 0.5" + 1" + 1.5" — - - Formatted: Centered, Tab stops: 0.38", Left + 0.75", Left Sheet Of COUNTY OF ROANOKE �4Y/1/16 15A-11 INSPECTION AND ENFORCEMENT MEMORANDUM OF UNDERSTANDING (MOU) FOR ADMINISTRATION OF THE VIRGINIA EROSION AND SEDIMENT CONTROL PROGRAM (VESCP) AND THE VIRGINIA STORMWATER MANAGEMENT PROGRAM (VSMP) BETWEEN THE COUNTY OF ROANOKE, VIRGINIA AND THE TOWN OF VINTON, VIRGINIA DRAFT, JANUARY 20, 2015 THIS MEMORANDUM OF UNDERSTANDING (MOU) is made and entered this day of 2016, by and between the County of Roanoke, Virginia, a political subdivision of the Commonwealth of Virginia, hereinafter referred to as the "County", and the Town of Vinton, a political subdivision of the Commonwealth of Virginia, hereinafter referred to as the "Town". Purpose of the Memorandum WHEREAS, clean water is crucial to the quality of jAifl both County and Town residents as well as the economic vitality of the region and the Commonwealth of Virginia; and, WHEREAS, the County is currently recognized as the local "Virginia Erosion and Sediment Control Program (VESCP) Authority" within the County and the Town to regulate stormwater runoff from construction sites; and, WHEREAS, the County currently reviews and inspects new land disturbing activities for conformance with the Stormwater Management Design Standards, Hydrologic Design, and Best Management Practices (BMPs) of the Town; and WHEREAS, the VESCP and the Virginia Stormwater Management Program (VSMP) are becoming increasingly more inter -related and com 1 to administer; and WHEREAS, the Town has determined that it would be beneficial for the County to operate as the local VSMP Authority in the Town; and the County is willing to serve in this capacity. NOW THEREFORE, the County and the Town agree that their respective responsibilities are as follows: A. Responsibilities of the County: 1. The County shall continue to be the the local "VESCP Authority" (in the Town. 2. The County, upon approval by the Roanoke County Board of Supervisors of the revised Stormwater Management Ordinance, upon approval of this Memorandum of Understanding, and upon approval by the Virginia State Water Control Board shall become the local "Virginia Stormwater Management Program (VSMP) Authority" in the Town. 3. Roanoke County shall possess the authority and perform the duties of the local "VESCP Authority" as set forth in Chapter 8.1 of the Code of the County of Roanoke; Title 62.1, County of Roanoke and Town of Vinton VESCP/VSMP MOU Agreement -1/20/16 DRAFT Page 1 Chapter 3.1, Article 2.3 of the Code of Virginia; and 9VAC25-840; as amended, or as set forth in such ordinances, statutes, and regulations that are enacted to succeed the above. 4. Roanoke County shall possess the authority and perform the duties of the local "VSMP Authority" as set forth in Chapter 23 of the Code of the County of Roanoke; Title 62. 1, Chapter 3. 1, Article 2.3 of the Code of Virginia; and 9VAC25-870; as amended, or as set forth in such ordinances, statutes, and regulations that are enacted to succeed the above. B. Responsibilities of the Town: The Town shall adopt a Stormwater Management Ordinance that recognizes Roanoke County as the local VESCP authority. 1W IqEL 2. The Town shall not issue any permits for activities that requ `"'"`. SCP and/or VSMP permits, until the VESCP and/or VSMP permits are issued. C. Previous Agreements X,,& 1. Previous agreements between the Town and the County concerning e VESP and the VSMP are void and superseded by this agreement. D. Fees X ""W� Awwhh, ?X,., 1. Roanoke County shall collect fees from regulated land -disturbing activities occurring within the Town, in accordance with the fee schedule adopted by the Roanoke County Board of Supervisors. 2. The fees for regulated land -disturbing activities within the Town shall be the same as those for regulated land -disturbing activities in other parts of the County. D. Amendments and Modifications This Memorandum of Understanding may be amended at any time by mutual consent of the parties, in writing. E. Termination This agreement may be terminated by either party upon giving 90 days written notice. If this agreement is terminated, the Town understands that it would need to obtain Virginia State Water Control Board approval to become the local VESCP and VSMP authority within the Town. F. Effective Date This Memorandum of Understanding shall become effective upon the endorsement of the parties as well as adoption of applicable ordinances; and approval by the Virginia State Water Control Board County of Roanoke and Town of Vinton VESCP/VSMP MOU Agreement -1/20/16 DRAFT Page 2 for transfer of the local VSMP from the Town to the County; and it shall remain in effect unless terminated by one of the parties as noted above. In Witness Whereof, the parties herein have caused this document to be executed as the date of the last signature shown below. FOR ROANOKE COUNTY: Approved as to Form: Ruth Allen Kuhnel County Attorney BOARD OF SUPERVISORS OF COUNTY OF ROANOKE, VIRGINIA am Thomas C. Gates Countv Administrator STATE OF VIRGINIA, CITY/COUNTY OF ilk, to -wit: The foregoing instrument was acknowledged before me this day of , 20 , by Thomas Gates, County Administrator on behalf of the County of Roanoke, Registrati My comfy Notary Public (SEAL) County of Roanoke and Town of Vinton VESCP/VSMP MOU Agreement -1/20/16 DRAFT Page 3 FOR TOWN OF VINTON: Approved as to Form: TOWN COUNCIL OF TOWN OF VINTON, VIRGINIA :1 Theresa Fontana Barry Thompson Town Attorney Interim Town Manager STATE OF VIRGINIA, CITY/COUNTY OF to -wit: Ar The foregoing instrument was acknowledged before me this day of 120_, by Barin Thompson, Interim Town Manager on behalf of the Town of Vinton, Virginia. Registr: My con Notary Public County of Roanoke and Town of Vinton VESCP/VSMP MOU Agreement -1/20/16 DRAFT Page 4 ACTION NO. ITEM NO. M-2 AT A REGULAR MEETING OF THE BOARD OF SUPERVISORS OF ROANOKE COUNTY, VIRGINIA HELD AT THE ROANOKE COUNTY ADMINISTRATION CENTER MEETING DATE: January 26, 2016 AGENDA ITEM: Work session to review with the Board of Supervisors the mid- year fiscal year 2015-2016 revenues and expenditures SUBMITTED BY: Christopher Bever Director of Management and Budget APPROVED BY: Thomas C. Gates County Administrator COUNTY ADMINISTRATOR'S COMMENTS: SUMMARY OF INFORMATION: This time has been scheduled to discuss the second quarter (mid -year) fiscal year 2015- 2016 revenues and expenditures. The attached Power Point presentation will be shown. Page 1 of 1 W FM D Z W am w LU .o z a U) Qa Y L LU U) Z Lu 0 W FM �`� � > (3) C:) WN Q �N I.L = U) N Cf O L >= Q LL L N m � Q � L I1/ W LL H u 0 FL - am W Z W i LU N N N ry (6 L U) x E E0 x m -I N ~N N > r O V � co M r J\ U. 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