A Total Maximum Daily Load (TMDL) is a regulatory term in the U.S. Clean Water Act (CWA), describing a value of the maximum amount of a pollutant that a body of water can receive while still meeting water quality standards. Alternatively, TMDL is an allocation of that water pollutant deemed acceptable to the subject receiving waters.
TMDLs have been used extensively by the United States Environmental Protection Agency (EPA) and state environmental agencies in implementing the CWA by establishing maximum pollution limits for industrial wastewater dischargers. EPA published regulations in 1992 establishing TMDL procedures. Application of TMDL has broadened significantly in the last decade to include many watershed-scale efforts. This process incorporates both point source and nonpoint source pollutants within a watershed.

Construction sites that do not control the disturbed soils they may be removing for a new building eventually end up in the streams as sediment. The sediment builds up in the stream and puts stress on the survival of the insects. Controls are monitored so that the least amount of sediment as possible is added to the streams. Virginia's DCR has regulations and standards that construction sites have to follow and to minimize the erosion impact on our streams.

When large rains wash mud, oils, pollution in general from our streets and pesticides from our fields it usually goes directly into our streams. Most communities do not send the runoff through a wastewater facility where it could be cleaned before entering the streams so this dirty water is contributing to the pollution and sediments in the streams adding to the impairments of many of VA's streams. Solutions to runoff include: rain gardens, riparian buffers, and better drainage systems, street sweeping, stormwater detention ponds. These solutions effectively reduce the release of pollutants into our streams.