Update: Chesapeake Bay TMDL

In order to reduce pollutants in the Chesapeake Bay, the U.S. Environmental Protection Agency (EPA) in 2010 established the Chesapeake Bay Total Maximum Daily Load (Bay TMDL) for nitrogen, phosphorus, and sediment. Each state in the watershed has been given a quota on how much of these pollutants it may contribute to the bay on an annual basis. To achieve these quotas and meet the water quality standards in the bay by 2025, each state must implement significant reductions across several pollution source sectors. This article describes how state and local governments in the watershed plan to achieve the reductions. Most jurisdictions are using models to help them estimate pollutant loads and evaluate alternative compliance scenarios in terms of efficiency and cost. National Pollution Discharge Elimination System (NPDES) permits will be effective for limiting discharges from municipal and industrial wastewater treatment plants, concentrated animal feeding operations, and Phase I/Phase II Municipal Separate Storm Sewer Systems (MS4s). The first phase of Watershed Implementation Plans (WIPs), which were broad plans showing how reductions will be achieved, were delivered to EPA in 2010. Phase II WIPs were developed by the states in 2011 to explain how the targeted reductions will be achieved. These Phase II WIPs were prepared with significant input from local jurisdictions. Jurisdictions with Phase I MS4 permits and statewide agencies such as the Maryland State Highway Administration (MD SHA), have been leading the way in WIP. Counties in Maryland and Virginia plan to comply with permit requirements in a variety of ways, including retrofit of untreated impervious areas with stormwater management, street sweeping, and stream and outfall restoration. The MD SHA currently is developing its own system-wide TMDL compliance implementation plan. The Virginia Department of Transportation has developed a WIP that includes street sweeping, increased implementation of erosion and sediment control on disturbed sites, and filtration devices. In the District of Columbia, the MS4 permit has been appealed, which has stayed development of an implementation plan. The estimated costs of compliance with the NPDES permit conditions, which will be substantial, are the responsibility of the local jurisdictions, utilities, and agencies that hold the permits.


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Media Info

  • Media Type: Print
  • Features: Illustrations; Photos;
  • Pagination: pp 40-43
  • Serial:

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Filing Info

  • Accession Number: 01447091
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 24 2012 9:34AM