Final TMDL Approved by EPA: Marsh Run Watershed

The Marsh Run watershed is located entirely within Washington County, Maryland. Washington County is bordered by Pennsylvania to the north and by the far shore of the Potomac River, Virginia, and West Virginia to the south. According to the Chesapeake Bay Program’s Phase 5.3.2 watershed model, the total drainage area of the Maryland 8-digit watershed is approximately 13,430 acres, not including water/wetlands, and includes only one major tributary (Saint James Run) to Marsh Run. Approximately 30 acres of the watershed area is covered by water. The watershed is located in the Highland region, one of three distinct eco-regions identified in the Maryland Department of Natural Resources Maryland Biological Stream Survey (MDDNR MBSS) Index of Biological Integrity (IBI) metrics.  The total population in the Marsh Run watershed is approximately 10,900. There are no “high quality,” or Tier II, stream segments (Benthic-IBI and Fish-IBI aquatic life assessment scores > 4 [scale 1-5]) located within the Marsh Run watershed.  Tier II segments would require the implementation of Maryland’s anti-degradation policy.
The Maryland Department of the Environment (MDE) identified the waters of the Marsh Run watershed on the State’s 2018 Integrated Report as impaired by sediment.  A data solicitation for sediment was conducted by MDE in May 2018, and all readily available data has been considered.
The TMDL, available below, will ensure that watershed sediment loads are at a level to support the designated uses for the Marsh Run watershed, and more specifically, at a level to support aquatic life. 

Total Maximum Daily Load of Sediment in the Marsh Run Watershed, Washington County, Maryland

(Approved on September 12, 2019)

EPA's Decision Letter EPA's Decision Letter (4623KB)
​Fact Sheet Marsh_Run_Sed_TMDL_FactSheet.pdf (304KB)
Main Report

Marsh_Run_Sed_TMDL_final.pdf (1686KB)

Point Source Technical Memorandum Marsh_Run_Sed_TMDL_PS_TechMemo.pdf (228KB)
Nonpoint Source Technical Memorandum Marsh_Run_Sed_TMDL_NPS_TechMemo.pdf (219KB)
Comment Response Document Marsh_Run_Sed_TMDL_CRD.pdf (116KB)

Additional Supporting Information

Biological Stressor Identification Marsh Run Watershed Report (546KB)

Biological Stressor Identification Methodology (459KB)

Nontidal Sediment TMDL Methodology Report (361KB)

Addendum to the Nontidal Sediment TMDL Methodology Report (23KB)


Contact Information

Please direct questions or comments concerning this project to Maryland's TMDL Program at (410) 537-3818.