MS4 Watershed Activities

This website provides information about watershed planning, assessment, and monitoring by Prince George’s County Department of the Environment (DoE). It also serves as a public repository for the resources developed from the County’s watershed management.

Context

In fulfillment of the federal Clean Water Act (CWA), the Maryland Department of the Environment (MDE) issued Prince George’s County (the County) its first permit under its National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) permitting program in 1993. The CWA prohibits the discharge of “pollutants” through a “point source” into a water of the United States unless they have a NPDES permit, which contains:

• Limits on what the permittee can discharge,
• Requirements on what it must monitor and report,
• And other provisions to ensure that the discharge do not harm water quality or people's health.

Stormwater carries pollutants through MS4s and often discharges them into local water bodies without treatment (e.g., the Anacostia or Patuxent Rivers). The NPDES MS4 permitting program addresses this by regulating stormwater discharges from MS4s.

Since 1993, the Maryland Department of the Environmental (MDE) renewed the County’s NPDES MS4 permit four times (in 1999, 2004, 2014, and 2022). The MDE issues NPDES MS4 permits in five-year cycles, which enables regulators and permit holders to adjust permit objectives and expectations that might require adjustments to their stormwater programs.

Website Layout

This website is organized into two main tracks: (1) Watershed Management and (2) Watershed Monitoring. The topics for Watershed Management build on the preceding pages, while the pages in the Watershed Monitoring track can be viewed in any order after the initial page.