9 Va. Admin. Code § 25-875-580

Current through Register Vol. 41, No. 9, December 16, 2024

Section 9VAC25-875-580 - Water quality design criteria requirements

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 total phosphorus load of new development projects shall not exceed 0.41 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.

9 Va. Admin. Code § 25-875-580

Derived from Virginia Register Volume 40, Issue 8, eff. 7/1/2024.

Statutory Authority: § 62.1-44.15:28 of the Code of Virginia; Chapters 68 and 758 of the 2016 Acts of Assembly.