County TMDL Action Plans

Chesapeake Bay TMDL Action Plan

In 2010, EPA established the Chesapeake Bay Total Maximum Daily Load (TMDL) allocations, a comprehensive pollution diet for the Chesapeake Bay with accountability measures to restore clean water in the Bay and its tributaries. A TMDL establishes the maximum amount of a pollutant that can enter a water body without violating water quality standards.

The Chesapeake Bay TMDL requires Municipal Separate Storm Sewer System (MS4) permit holders such as Prince William County to achieve specific pollutant reductions during each permit cycle. The pollutants of concern (POC) include nitrogen, phosphorus and sediment and the reductions required are expressed in terms of pounds per year. As established by the Virginia Department of Environmental Quality (DEQ), Prince William County must reduce its share of these POC's by 5% during the current MS4 permit cycle (2013–2018), an additional 35% (40% total) during the second permit cycle (2018–2023), and the final 60% (100% total) during the third permit cycle (2023–2028).

The County's MS4 permit requires that County submit a detailed plan to DEQ to meet the 5% reduction requirements within the first permit cycle. This plan, called the Chesapeake Bay TMDL Action Plan, outlines the specific projects and programs that will be implemented to meet the 5% reduction.

Phase I Chesapeake Bay TMDL Action Plan

Phase II Chesapeake Bay TMDL Action Plan

Local TMDL Action Plans

In addition to the Chesapeake Bay TMDL Action Plan described above, the County's MS4 permit requires the development and implementation of action plans for impaired streams, for which, the Virginia State Water Control Board has established a Total Maximum Daily Load (TMDL)

Bacteria TMDL Action Plan (E. coli)

PCB TMDL Action Plan (Polychlorinated Biphenyl)

Benthic TMDL Action Plan (Sediment)