Section 85. Stormwater management impoundment structures or facilities

A. Stormwater management wet ponds and extended detention ponds that are not covered by the Impounding Structure Regulations (4VAC50-20) shall, at a minimum, be engineered for structural integrity for the 100-year storm event.

B. Construction of stormwater management impoundment structures or facilities may occur in karst areas only after a study of the geology and hydrology of the area has been conducted to determine the presence or absence of karst features that may be impacted by stormwater runoff and BMP placement.

C. Discharge of stormwater runoff to a karst feature shall meet the water quality criteria set out in 9VAC25-870-63 and the water quantity criteria set out in 9VAC25-870-66. Permanent stormwater management impoundment structures or facilities shall only be constructed in karst features after completion of a geotechnical investigation that identifies any necessary modifications to the BMP to ensure its structural integrity and maintain its water quality and quantity efficiencies. The person responsible for the land-disturbing activity is encouraged to screen for known existence of heritage resources in the karst features. Any Class V Underground Injection Control Well registration statements for stormwater discharges to improved sinkholes shall be included in the SWPPP.

Historical Notes

Former 4VAC50-60-85 derived from Volume 27, Issue 26, eff. September 13, 2011; amended and renumbered, Virginia Register Volume 30, Issue 02, eff. October 23, 2013.

Statutory Authority

§§ 62.1-44.15:25 and 62.1-44.15:28 of the Code of Virginia.