Virginia Regulatory Town Hall View Comments

Department of Environmental Quality

State Water Control Board

Guidance Document Change: This guidance document has been developed to assist the public and the development community in determining the policies and procedures, which apply to land development in the Commonwealth of Virginia where DEQ serves as the Virginia Stormwater Management Program (VSMP) authority and/or the Virginia Erosion & Sediment Control Program (VESCP) authority. It contains information primarily concerned with the design guidelines for Erosion & Sediment Control Plans and Stormwater Management Plans.

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8/25/22 3:35 pm

Commenter: Lisa Koerner Perry

DEQ Guidance Memo 22-2012

How were ESC practices chosen for inclusion in this document? Many common practices which would benefit from additional guidance are not included
Pg 11 – 2.306.B – typo “boding” should be “bonding”
Pg 15 – Is 3.301.E meant to remove the provision in the regulations that states “Predevelopment runoff calculations utilizing other hydrologic conditions may be utilized provided that it is demonstrated to and approved by the VSMP authority that actual site conditions warrant such considerations.”? It’s confusing to have the direct wording of point E, and then also reference 9VAC25-870-66.E.
Pg 15- 3.302.1.A.1 – The language could be clearer about what to do when you hit the 1% limit at the confluence with a natural channel. I think this is the point of all the language about “flood-prone area” under the Channel Protection section, but it could be stated more clearly.
Pg 19 – 3.302.4.A - Is there a preferred or recommended methodology for mapping the water surface elevation of a natural system?
Pg 24 - 3.305.1 – Including tables that show parameters for land slope of “Greater than 10%” seems strange. Would you allow us to claim sheet flow discharge on a slope greater than 10%?
Pg 28 – 3.305.2.H – 200’ is a really long level spreader. Constructability is questionable at this length.
Pg 29 – 3.305.2.M – Rock is given as an example of a material that may be used to construct level spreaders. Will anything change about the water quality practice “Sheet Flow to Conserved Open Space” that requires a rigid lip?
Pg 29 – 3.306.B – No KAF is provided for the 1-year storm – how is this to be applied in situations where energy balance equation is being used?
Pg 29 – 3.306.B – How are we to determine what % of the drainage area is in karst? The area that has visible surface depressions only? Typically, the entire site will be underlain with limestone – meaning 100% is usually “karst”, so the 0-100% DA in karst column seems odd to me.
Pg 30 -31 – 3.306.I – No detention practices are listed as preferred. Even with using runoff reduction practices, there is typically still some detention needed (especially for commercial or other highly impervious developments). Additionally, runoff reduction practices have to be lined with impermeable liners in karst per BMP Clearinghouse specs, thus reducing runoff reduction potential. Would underground detention be the recommended detention method in karst topography?
Pg 33 – 4.303 – I did not locate a specific definition for “Brownfield”.
Pg. 37 – 4.404.A – Required total phosphorus load reduction almost never “cannot be achieved onsite through the implementation of ESD, RR, and PR practices.” If this provision were to be strictly implemented, there would be almost no sites eligible for offsite compliance options. Not sure if this is the intention or not.
Pg 38 – 5.200.B – “…should deviate from the pre-development condition by no more than plus or minus 10%” May consider adding “in total area”.
Pg 39 - 5.302.D – This is very impractical. At the time of design, it is often not known what the final site soil composition will be. Unsuitable material may be unexpectedly encountered, depth of topsoil may vary from expectations, sites may decide to initially sell their topsoil to avoid having to stockpile onsite, and then purchase topsoil later to finish the job. Items 3 and 4 are especially impractical, as they suggest retrofitting a completed stormwater plan if the onsite HSG results come back different than expected. I don’t see anyone doing anything other than options 1 and 2.
Pg 39- 5.302 -It is unclear to me if the CN adjustment for HSG correction meant to be used for quantity compliance modeling, or are we also supposed to reflect this in the site tab of the VRRM spreadsheet as well? I would not advocate to require HSG correction on the VRRM spreadsheet, but it does set us up for an overly complicated situation if we are using CN adjustment for runoff reduction practices.
Pg 39-40 – 5.302.D –Section “D” is used twice, should be “E” on pg. 40.
Pg 40 – CN Adjustment table – there are several other land cover categories that I use on a regular basis. This appears to lump many diverse land cover categories into “Open Space”. I suppose this is just for demonstration of the selected categories. If you are not going to cover every category, I think we could get the idea from just one category example.
Pg 40 – I forsee many debates and interpretations of “not directly connected to the stormwater conveyance system”.

CommentID: 127421