Water Quality Analyses (WQA) with EPA Concurrence of MDE's Findings: Potomac River Washington County

The Potomac River Washington County watershed is located in the Upper Potomac River sub-basin (021405) and covers approximately 85 square miles.   The mainstem flows 68 miles from Hancock, MD southeastward to the Shenandoah River, creating the border between Maryland and West Virginia. 

The Potomac River Washington County watershed (basin code 02140501) was identified on the Integrated Report under Category 5 as impaired by nutrients and suspended sediments (1996), methylmercury (2002), evidence of biological impacts (2002), and polychlorinated biphenyls (PCBs) in fish tissue (2008). 

The report available below provides an analysis of recent monitoring data to address whether or not the watershed is still impaired by nutrients. The study demonstrates that both applicable criteria for nutrients and the designated uses supported by this criteria are being met in the Potomac River Washington County 8-digit basin; therefore, a nutrient TMDL is not required. 

Although the waters of the Potomac River Washington County do not display signs of eutrophication, the State reserves the right to require future controls in the Potomac River Washington County watershed if evidence suggests nutrients from the basin are contributing to downstream water quality problems. Other substances not addressed at this time, but identified on Maryland’s 303(d) list as impairing the Potomac River Washington County 8-digit basin, will be addressed in the future. 

WQA of Eutrophication for Potomac River Washington County, Washington County, Maryland

(EPA Concurrence: February 1, 2011)

EPA's Decision Letter EPA's Decision Letter

Main Report 

Potomac_WaCo_Nut_WQA_09302010_final.pdf (1266KB)

Comment Response Document

Potomac_River_Washington_CO_Nut_CRD_final.pdf (10KB)

Contact Information

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