Total Maximum Daily Load (TMDL) is the amount of pollution a stream can receive and still meet Water Quality Standards, which are regulations that set numeric or narrative limits on pollutants. Local TMDLs are required for waterbodies that have been determined to be impaired by the Virginia Department of Environmental Quality (DEQ) for their designated beneficial uses, such as drinking water, swimming, fishing, shell-fishing, and aquatic life. The Rappahannock-Rapidan Region contains 550 miles of impaired streams, mostly due to E. coli bacteria, which poses risks for fishing and swimming.
A TMDL Study identifies sources of the pollutant(s) causing the impairment and the pollutant reduction needed to meet water quality standards. It considers both point sources such as municipal wastewater and industrial discharges, and non-point sources such as residential pet waste or agricultural runoff. After DEQ submits the draft TMDL Report, the Environmental Protection Agency (EPA) has 30 days to review and approve the TMDL.
Following EPA’s approval of the TMDL, a TMDL Implementation Plan is later developed to bring the impaired water body up to water quality standards. Implementation Plans include a schedule of actions, costs, and monitoring. Although not a federal requirement, Virginia state law requires the development of TMDL Implementation Plans.
Regional and State Resources
For information on TMDLs completed by RRRC on behalf of DEQ, see the following pages:
For information on TMDL Implementation Plans completed by RRRC on behalf of DEQ, see the following pages:
Virginia 2018 Water Quality Assessment Report DEQ determines whether a waterbody is impaired through water quality monitoring and assessment. Every even numbered year, Virginia submits a list of the waters found to be impaired, referred to as the 303(d) list, to the Environmental Protection Agency.
Impaired Waters by County (August 2008): Spreadsheet of all impaired waters in the Rappahannock-Rapidan region by county, year and impairment type.
Additional state-wide information on local TMDLs can found on VDEQ’s TMDLs in Virginia webpage.