Virginia Regulatory Town Hall View Comments

Department of Environmental Quality

State Water Control Board

Guidance Document Change: The Virginia Stormwater Management Handbook, Version 1.0 (Handbook) provides guidance to implement water quantity and water quality criteria in the Virginia Erosion and Stormwater Management Regulation, 9VAC25-875, effective July 1, 2024. The Handbook replaces nine guidance documents, listed below, that the Department of Environmental Quality (DEQ) plans to rescind effective July 1, 2025: 1. Virginia Erosion and Sediment Control Handbook, Third Edition, 1992 2. Virginia Stormwater Management Handbook, First Edition, 1999 3. Guidance Document on VSMP Site Inspection Strategies 4. Guidance Document on Utilization of Nonpoint Nutrient Offsets 5. Guidance Memo No. 14-2002 Implementation Guidance for the 2009 General Permit for Discharges of Stormwater from Construction Activities, 9VAC25-880 6. Guidance Memo No. 14-2014 Implementation Guidance for Section 47 (time limits on applicability of approved design criteria) and Section 48 (grandfathering) 7. Guidance Memo No. 15-2003 Postdevelopment SW Mgmt Implementation Guidance for Linear Utility Projects 8. Guidance Memo No. 22-2011 Streamlined Plan Review for Construction Stormwater Plans and Erosion and Sediment Control Plans submitted by a Licensed Design Professional and reviewed by a Dual Combined Administrator for Erosion and Sediment Control and Stormwater Management 9. Guidance Memo No. 22-2012 Stormwater Management and Erosion & Sediment Control Design Guide The reason that the guidance documents will be rescinded effective July 1, 2025, through a separate Town Hall notice, is that they have been incorporated into the Handbook to reduce complexity and improve the ease of use. A one-year transition period allows plans and permit applications submitted between July 1, 2024 and June 30, 2025 to utilize either the existing manuals, handbooks and guidance or the Virginia Stormwater Management Handbook, Version 1.0. The Handbook is available as a Portable Document Format (pdf) file and online at https://online.encodeplus.com/regs/deq-va/index.aspx. Due to the large file size and number of pages in the Handbook, DEQ recommends using the web-based version to review it and submit comments. Chapters, best management practice specifications, and other information from the Handbook may be downloaded from the website as pdf files. Written comments on the Handbook may be submitted directly through the enCodePlus website that is hosting the handbook, as well as through the Town Hall website, and by email to the contact address provided with this notice. Instructions for submitting comments through the host website are available from the “Comment” link on the webpage banner. DEQ will use comments received during this forum and after the Handbook becomes effective to maintain its content consistent with the process for updates and revisions described in Chapter 1: Introduction. DEQ formed a Stakeholders Advisory Group (SAG) to help develop the Handbook and its content. The SAG met 12 times between July 2022 and October 2023. Members of the SAG were provided an opportunity review and provide feedback on a draft version of the Handbook during November 2023. DEQ reviewed and revised the draft Handbook based on the feedback SAG members provided. Handbook Version 1.0 reflects those revisions. Two Excel spreadsheets with comments SAG members submitted on the draft version of the Handbook, and responses to those comments, are available from the DEQ website at: https://www.deq.virginia.gov/our-programs/water/stormwater/stormwater-construction/handbooks under the Virginia Stormwater Management Handbook, Version 1.0 banner.

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3/13/24 11:25 am

Commenter: Sheldon Bower, PE Parker Design Group, Inc

Limits of Analysis and "1% Rule"

Chapter 5 and Appendix A with regards to Limits of Analysis and the “1% Rule”. The existing language in the Handbook lacks consistency with current regulations and Virginia Erosion and Sediment Control Handbook, Chapter 4. According to these standards, a receiving channel can be deemed sufficient if the total drainage area to the point of analysis is 100 times greater than the contributing drainage area of the project site. If the channel meets adequacy criteria, there is no justification or advantage in implementing any detention, specifically any measures meeting energy balance, as this would be inconsistent with standards accepted by DEQ in the past.

When a manmade system discharges into a sizable channel, either manmade or natural coinciding with the limits of analysis, further flow reduction becomes unnecessary. Under such circumstances, requiring additional flow reduction is unwarranted. The current language could mandate the needless detention of runoff, particularly for sites situated adjacent to or upstream of large bodies of water capable of accommodating increased runoff. For instance, sites directly discharging into the Lower James River, Chesapeake Bay, Smith Mountain Lake, or Lake Anna should not be compelled to restrict flows based on the energy balance equation.

These channels, whether manmade or natural already meet the 1% rule and are unaffected by the minimal flows from typical development sites. Implementing additional detention measures would have negligible impact on the large channel while significantly increasing costs to the development.

Recommend adding language that supports "No additional measures are required if discharging to a natural or manmade channel with a contributing drainage area 100 times or greater than the site contributing drainage area."

CommentID: 222296