Commenter:
Mike Short, Alex Deuson, Michael Hare; Tetra Tech
ESC and SWM Clarifications
Line 62: Recommend clarifying “watercourse” within the “Adequate channel” definition or create a new definition. The word “watercourse” can be implied as a natural channel in its context of the “Adequate channel” definition; however, the word “adequate” (line 3041) is implied as a man-made channel. Suggest “watercourse” be defined or clarified as a natural channel, man-made channel, or restored channel. The whole document should be reviewed for consistency in definition and context of channels and watercourses to avoid confusion.
Lines 2609-2610: Consider specifying a reasonable time period (i.e., 21 days) within which completion of stabilization activities is required. Deferring responsibility for determining when complete stabilization is required to the VESMP Authority produces wide-ranging and arbitrary timeframes, which are often too lenient (lengthy) to adequately protect Commonwealth resources or too strict (short) to enable practicable compliance. Specifying a timeframe for completion of stabilization would both better protect the resources of the Commonwealth and enable the development community to plan and implement required compliance measures.
Line 2615: Consider expounding on what makes use of a skimmer device infeasible, i.e., “unless documented as technically infeasible or unreasonably cost prohibitive”.
Line 2881: Consider specifying the time period within which completion of stabilization is required.
Line 2948: Item 16 should be qualified to state its criteria do NOT apply to underground utility lines installed within the limits of a permitted land disturbance activity otherwise controlled by Department-approved methods. Item 16 contains several requirements which are unreasonable for, and should not apply to, construction sites where the chief land disturbing activity is not the installation of underground utility lines.
Lines 2966-3082: Part 25-875-560 contains the erosion and sediment control minimum standards, commonly referred to as MS-19, except that the numbering ceases at Item 16. Beginning on line 2966, Items 17, 18, and 19(a-n) are erroneously listed as a continued subset of Item 16 (specifically, sub-items g-i).
Line 3321: Consider modifying item E. to expand the specification of “good hydrologic condition” to include allowable predevelopment cover types. For example, Pennsylvania regulations’ allowable predevelopment cover types are ONLY forested, meadow, and impervious. Doing so would preclude arbitrary assignment of predevelopment cover types by permittees and better align with water quality objectives in the VRRM, which only considers FOS/COS, Turf, and Impervious.
Line 3415: Please reconsider the use of the Modified Rational Method for drainage areas of 200 acres or less. Acreage is more limited in other requirements (PWC DCSM – 20 acres), and the method is simplified and less accurate when determining detention volumes during hydraulic basin routing (Iowa Design Manual 2B-1 limits hydraulic routing to 5 acres).
Proprietary BMPs for post-construction stormwater management are discussed; however, they are not discussed for during-construction erosion and sediment control. Recommend a section discussing the use of the expansive (since the 1992 Virginia ESC Handbook was written) industry and research of proprietary erosion and sediment control measures.
