Final TMDLs Approved by EPA: Potomac River Washington County

The Potomac River Washington County watershed is located in the Upper Potomac River sub-basin of the Chesapeake Bay watershed and covers approximately 58,580 acres.  The Washington County portion of the Potomac River is defined as the reach that starts at the confluence of the Potomac River with the Little Tonoloway Creek and ends at the confluence with the Shenandoah River.  The 68 mile southeastward journey of the river creates the border between Maryland and West Virginia.  Major tributaries include Camp Spring Run, Ditch Run, Downey Branch, and Greenspring Run.  The region is mostly forested and rural.  The two largest urban centers in the watershed are Hancock and Williamsport.

The Maryland Department of the Environment (MDE) has identified the waters of the Potomac River Washington County on the State’s 2008 Integrated Report as impaired by nutrients – phosphorus (1996), sediments (1996), methylmercury (2002), impacts to biological communities (2002), and polychlorinated biphenyls (PCBs) in fish tissue (2008).  The designated use of the Potomac River Washingto n County mainstem and its tributaries is Use I-P (water contact recreation, protection of aquatic life, and public water supply), except for Camp Spring Run, which is designated as Use III-P (nontidal cold water and public water supply).

The TMDL, available below, addresses the 1996 sediments listing, for which a data solicitation was conducted, and all readily available data from the past five years were considered. The TMDLs set the maximum load limit for sediments, and provides load allocations to point and nonpoint sources. A Water Quality Analysis (WQA) for eutrophication to address the nutrients/phosphorus listing is scheduled to be submitted to the EPA in 2010.  In the 2012 Integrated Report, the listing for impacts to biological communities will include the results of a stressor identification analysis, and the PCBs in fish tissue and methylmercury listings will be addressed at a future date. 

Total Maximum Daily Load of Sediment in the Potomac River Washington County Watershed, Washington County, Maryland

(Approved on September 30, 2011)

EPA's Decision Letter EPA's Decision Letter 
(Does not include MDE's requested revisions)
MDE's Edits to EPA's Decision Letter MDE's Decision Letter Edits (35KB)
Main Report Potomac_Wash_Co_Sed_TMDL_Final  (669KB)
Point Source Technical Memorandum Potomac_Wash_Co_Sed_TMDL_PS_techmemo_Final (24KB)
Nonpoint Source Technical Memorandum Potomac_Wash_Co_Sed_TMDL_NPS_techmemo_Final (15KB)
Comment Response Document Potomac_Wash_Co_Sed_CRD_Final (17KB)

Additional Supporting Information

Biological Stressor Identification Potomac River Washington County Watershed Report (620KB)
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.