The North Branch of the Potomac River forms the border between Maryland and West Virginia from its origin at the Fairfax Stone downstream to its confluence with the South Branch of the Potomac. The Upper North Branch of the Potomac River is defined as the reach between its headwaters in West Virginia and its confluence with the Savage River.
Upper North Branch Potomac River (basin code 02141005), located in Garrett County, Maryland, was identified on the State’s list of water quality limited segments (WQLSs) as impaired by metals (1996 listing), sediments (1996 listing), nutrients (1996 listing), low pH (1996 listing) and impacts to biological communities (2002/2004 listing). The listing for metals is based on a water quality assessment found in the 1996 305(b) report developed by the Maryland Department of Natural Resources (DNR).
The report available below provides an analysis of recent monitoring data, which shows that the aquatic life criteria and designated uses for metals are being met in the Upper North Branch Potomac River watershed, except for the following tributaries: Sand Run (12-digit basin – 021410050040), Laurel Run (12-digit basin – 021410050039), Three Forks Run (12-digit basin – 021410050048), and Elklick Run (12-digit basin – 021410050049), where exceedances of aluminum (Al) and manganese (Mn), and iron (Fe) criteria were found. Exceedances of Fe are also found at four stations along the Upper North Branch Potomac River mainstem above Jennings Randolph Lake. The analyses support the conclusion that a TMDL for metals in the entire Upper North Branch Potomac River 8-digit watershed is not necessary to achieve water quality standards, but TMDLs will be needed in certain subwatersheds.
The major sources of contamination are found in the tributaries and not in the watershed directly feeding the Upper North Branch Potomac River. TMDL development within the impaired tributaries will allow for water quality standards to be met in the mainstem. Therefore, barring the receipt of contradictory data, the report will be used to support a metals listing change for the Upper North Branch Potomac River from Category 5 (“waterbodies impaired by one or more pollutants requiring a TMDL”) to Category 2 (“Surface waters that are meeting some standards and have insufficient information to determine attainment of other standards”), when the Maryland Department of the Environment (MDE) proposes the revision of Maryland’s 303(d) List for public review in the future. Two samples were collected at each station. The assessment of metals in the tributaries and mainstem of the Upper North Branch Potomac River found two exceedances of Mn criterion in Laurel Run, Sand Run, Three Forks Run, and Elklick Run; two exceedances of Al criterion in Three Forks Runs; one exceedance of Al criterion in Laurel Run; seven exceedances of Fe criterion in the mainstem above Jennings Randolph Lake; two exceedances of Fe criterion in Laurel Run and Three Forks Run; and one exceedance of Fe criterion in Sand Run.
Based on impairment listing methodologies applied by MDE, the tributaries in the Upper North Branch Potomac River with two exceedances (Laurel Run (Mn and Fe), Elklick Run (Mn) and Three Forks Run (Mn, Al, and Fe)) are impaired and will be placed in Category 5 of the 303(d) List. The tributaries in the Upper North Branch Potomac River with only one exceedance (Sand Run (Fe) and Laurel Run (Al)) contain insufficient data to determine if an impairment exists. Additional monitoring is necessary to establish whether the exceedance was the result of a single anomalous event or further exceedances will occur resulting in an impairment. These tributaries will be placed in Category 3 (“waterbodies having insufficient data or information to determine impairment status”) of the 303(d) List. The North Branch Potomac River mainstem above Jennings Randolph Lake will be placed in Category 3 of the 303(d) List. The listings for low pH and impacts to biological communities will be addressed separately at a future date. The listings for sediments and nutrients will be addressed in 2006.
Although the waters of the Upper North Branch Potomac River watershed do not display signs of toxic impairments due to metals except for the individually impacted stream segments, the State reserves the right to require additional pollution controls in the Upper North Branch Potomac River watershed if evidence suggests that metals from the basin are contributing to downstream water quality problems.
WQA of Metals in Upper North Branch of the Potomac River, Garrett County, Maryland
(Concurrence November 15, 2006)
Comment Response Document
Please direct questions or comments concerning this project to Maryland's TMDL Program at (410) 537-3818.
1800 Washington Boulevard, Baltimore, MD 21230