A. In order to protect the quality of state waters and to control the discharge of stormwater pollutants from regulated activities, the following minimum design criteria and statewide standards for stormwater management shall be applied to the site.

1. New development. The For plans submitted on or after July 1, 2025 the total phosphorus load of new development projects shall not exceed 0.41 0.26 pounds per acre per year, as calculated pursuant to 9VAC25-875-590.

2. Development on prior developed lands.

a. For land-disturbing activities disturbing greater than or equal to one acre that result in no net increase in impervious cover from the predevelopment condition, the total phosphorus load shall be reduced at least 20% below the predevelopment total phosphorus load.

b. For regulated land-disturbing activities disturbing less than one acre that result in no net increase in impervious cover from the predevelopment condition, the total phosphorus load shall be reduced at least 10% below the predevelopment total phosphorus load.

c. For land-disturbing activities that result in a net increase in impervious cover over the predevelopment condition, the design criteria for new development shall be applied to the increased impervious area. Depending on the area of disturbance, the criteria of subdivision 2 a or 2 b of this subsection shall be applied to the remainder of the site.

d. In lieu of subdivision 2 c of this subsection, the total phosphorus load of a linear development project occurring on prior developed lands shall be reduced 20% below the predevelopment total phosphorus load.

e. The total phosphorus load shall not be required to be reduced to below the applicable standard for new development unless a more stringent standard has been established by a locality.

B. Compliance with subsection A of this section shall be determined in accordance with 9VAC25-875-590.

C. Nothing in this section shall prohibit a VESMP authority from establishing more stringent water quality design criteria requirements in accordance with § 62.1-44.15:33 of the Code of Virginia.

A. Compliance with the water quality design criteria set out in subdivisions A 1 and A 2 of 9VAC25-875-580 shall be determined by utilizing the Virginia Runoff Reduction Method or another equivalent methodology that is approved by the department.

B. The BMPs listed in this subsection the Virginia Stormwater Management Handbook are approved for use as necessary to effectively reduce the phosphorus load and runoff volume in accordance with the Virginia Runoff Reduction Method. Other approved BMPs found through the Virginia Stormwater BMP Clearinghouse may also be utilized. Design specifications and the pollutant removal efficiencies for all approved BMPs are found through the Virginia Stormwater Management Handbook and the Virginia Stormwater BMP Clearinghouse.

1. Vegetated Roof (Version 2.3, March 1, 2011);

2. Rooftop Disconnection (Version 1.9, March 1, 2011);

3. Rainwater Harvesting (Version 1.9.5, March 1, 2011);

4. Soil Amendments (Version 1.8, March 1, 2011);

5. Permeable Pavement (Version 1.8, March 1, 2011);

6. Grass Channel (Version 1.9, March 1, 2011);

7. Bioretention (Version 1.9, March 1, 2011);

8. Infiltration (Version 1.9, March 1, 2011);

9. Dry Swale (Version 1.9, March 1, 2011);

10. Wet Swale (Version 1.9, March 1, 2011);

11. Sheet Flow to Filter/Open Space (Version 1.9, March 1, 2011);

12. Extended Detention Pond (Version 1.9, March 1, 2011);

13. Filtering Practice (Version 1.8, March 1, 2011);

14. Constructed Wetland (Version 1.9, March 1, 2011); and

15. Wet Pond (Version 1.9, March 1, 2011).

C. Nonproprietary BMPs differing from those listed in subsection B of this section shall be reviewed and approved by the director in accordance with procedures established by the department.

D. Proprietary BMPs listed through the Virginia Stormwater BMP Clearinghouse are approved for use in accordance with the Virginia Runoff Reduction Method. Any proprietary BMP approved for use after July 1, 2020, must meet the requirements of § 62.1-44.15:28 A 9 of the Code of Virginia.

E. A VESMP authority may establish limitations on the use of specific BMPs in accordance with § 62.1-44.15:33 of the Code of Virginia.

F. The VESMP authority or department as the VSMP authority shall have the discretion to allow for application of the design criteria to each drainage area of the site. However, where a site drains to more than one HUC, the pollutant load reduction requirements shall be applied independently within each HUC unless reductions are achieved in accordance with a comprehensive watershed stormwater management plan in accordance with 9VAC25-875-660.

G. Offsite alternatives where allowed in accordance with 9VAC25-875-610 may be utilized to meet the design criteria of subsection A of 9VAC25-875-580.

H. Any publicly owned treatment works that is permitted under the watershed general VPDES permit pursuant to § 62.1-44.19:14 of the Code of Virginia and is constructing or expanding the treatment works, wastewater collection system, or other facility used for public wastewater utility operations may, in accordance with § 62.1-44.19:21.2 C of the Code of Virginia, permanently retire a portion of the publicly owned treatment works' wasteload allocation to meet the design criteria of subsection A of 9VAC25-875-580. Notice shall be given by such applicant to the VESMP authority and to the department.

Virginia Runoff Reduction Method: Instructions and Documentation, March 28, 2011 effective April 27, 2024

Virginia Erosion and Sediment Control Regulation Minimum Standard 19 in effect prior to July 1, 2014