Prince George's County

Watershed Implementation Plans and Assessments

In compliance with their 2014 National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) permit, Prince George’s County’s developed total maximum daily load (TMDL) restoration plans for each of the County’s watersheds with an U.S. Environmental Protection Agency (EPA)-approved TMDL that includes the County MS4. These plans outline the County’s efforts to prioritize and implement projects that address each EPA-approved TMDL with a stormwater wasteload allocation (SW-WLA).

These plans aim to:

  • Protect, restore, and enhance habitat in the watershed.
  • Restore watershed functions, including hydrology, water quality, and habitat, using a balanced approach that minimizes negative impacts.
  • Support compliance with regional, state, and federal regulatory requirements.
  • Increase awareness and stewardship within the watershed, including encouraging policymakers to develop policies that support a healthy watershed.
  • Provide stakeholders with the understanding that these plans cover several years and rely on adaptive management.
Stream restoration in Prince George’s County
Stream restoration in Prince George’s County

2024 Watershed Implementation Plans (WIPs)

Periodically, the Maryland Department of the Environment (MDE) requires local authorities to evaluate and update their TMDL restoration plans, developed as part of the County’s MS4 requirement. In 2024, the County updated its 2014 TMDL restoration plans (now referred to by Maryland Department of the Environment [MDE] as watershed implementation plans [WIPs]) to comply with 2022 MDE guidance documents.

Nutrient and Sediment Stormwater Wasteload Allocation (SW-WLA) WIPs

Pollutant Trackdown Strategies

In 2022, MDE released guidance on bacteria and polychlorinated biphenyl (PCB) trackdown strategies. Unlike nutrients and sediments, MDE does not require load reductions for bacteria and PCBs because of the various sources and characteristics of these pollutants. The bacteria and PCB trackdown guidance focuses on source identification and removal, rather than stormwater best management practices (BMPs), such as wet ponds. The County developed countywide bacteria and PCB strategies to cover all applicable watersheds.

2014 TMDL Watershed Restoration Plans

In 2014, the County developed restoration plans that served as blueprints for improving water quality and meeting pollutant reduction goals called for in approved local TMDLs. The following local TMDL restoration plans met the requirements under the County’s 2014 NPDES permit.

Green Infrastructure in Prince George’s County
Green Infrastructure in Prince George’s County

Additional Watershed Plans

2012 Chesapeake Bay TMDL WIP

In 2010, the EPA established the Chesapeake Bay nutrient and sediment TMDL to address water quality in the Chesapeake Bay, not local waterways. This means that even if agencies meet Chesapeake Bay’s TMDL reductions, local waterways could still remain impaired by nutrients or sediments. The EPA required each state in the Chesapeake Bay watershed to develop a Phase I WIP to serve as a guide for meeting the pollution-reduction targets for the Chesapeake Bay. In 2011, the County developed a countywide Chesapeake Bay Phase II WIP. The County finalized its Phase II WIP in 2012 and laid out a plan for BMP implementation and other restoration activities. MDE subsequently adjusted goals in 2018 but did not require updates to the Phase II WIP. In addition to urban stormwater runoff, Chesapeake Bay WIPs covered agricultural practices and upgrades to wastewater systems (e.g., municipal wastewater treatment plants, on-site wastewater systems).

Watershed Plans Associated with Grants

The County received two grants, which it used to develop restoration plans for watersheds that do not have local TMDLs but are part of the Chesapeake Bay TMDL load reductions.

Water Resources Element (WRE)

The Approved Water Resources Functional Master Plan for Prince George’s County fulfills the provisions of the Water Resources Element (WRE), one of several state planning requirements signed into law in Maryland on May 2, 2006, and mandated in HB 1141, Section 1.03 (iii) of Article 66B of the Annotated Code of Maryland. MDE recently mandated the WRE, which requires the County to perform a basic known water supply and demand comparative analysis to show whether there is an impact of proposed new development on the overall water supply. This master plan shows how the County can anticipate and manage drinking water supplies, wastewater effluents, and stormwater runoff to support existing and planned growth. Policy guidance for this plan came from the 2002 Prince George’s County Approved General Plan.

Watershed Assessments

The County's 2014 NPDES MS4 permit required the County to conduct watershed assessments by the end of that five-year permit term. The permit indicated that the watershed assessment should:

  1. Determine current water quality conditions.
  2. Include the results of a visual watershed inspection.
  3. Identify and rank water quality problems.
  4. Prioritize all structural and nonstructural water quality improvement projects.
  5. Specify pollutant load reduction benchmarks and deadlines that demonstrate progress toward meeting all applicable SW-WLAs.

The County completed its comprehensive watershed assessment report in 2018.

In addition, the County developed watershed existing conditions reports for the watersheds that had EPA-approved TMDLs in 2014. The reports began the watershed assessment process with a compilation and inventory of available information. See links to 2014 documents below.

Bioretention facility in Prince George’s County
Bioretention facility in Prince George’s County