HD15 - Application of the Postdevelopment Stormwater Management Technical Criteria, as Established in the Virginia Stormwater Management Program Regulations, in Areas with a Seasonal High Groundwater Table [HJR 587, 2015]


Executive Summary:
The 2015 Virginia General Assembly passed House Joint Resolution Number 587 (HJ 587). The resolution as passed states in part:

“That the Department of Environmental Quality be requested to study the application of the postdevelopment stormwater management technical criteria, as established in the Virginia Stormwater Management Program Regulations, in areas with a seasonal high groundwater table.”

The resolution specifies that the Department of Environmental Quality (DEQ) evaluate the existing design specifications for best management practices (BMPs) listed on the Virginia Stormwater BMP Clearinghouse and recommend design specification revisions to allow the effective use of these BMPs in areas with a seasonal high groundwater table (SHGT), if applicable. The purpose of this effort is to achieve greater flexibility in meeting the stormwater management requirements in areas with a SHGT.

This report summarizes the work completed for the study. DEQ reviewed scientific literature as well as stormwater design manuals used in other states. The literature search helped DEQ to better understand issues associated with a SHGT and formed the basis for the agency’s recommendations regarding the application of postdevelopment stormwater management technical criteria in areas with a SHGT. Based on work conducted in fulfillment of HJ 587, DEQ is proposing recommendations regarding regional methodology for compliance with the VSMP, additional BMPs, modifications to BMPs, adjustments to BMP efficiencies, and treatment train guidance.