The North Branch of the Potomac River Watershed

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Our watershed mapping project gives you detailed information on the North Branch Potomac watershed itself, containing data on watershed boundaries, stream locations, stream names, and water impoundments. The watershed itself has a very unique shape, having what looks like two “legs”. The “legs” themselves are formed by the continental divide. The water in between each leg flows through the Blackwater River watershed and eventually to the Gulf of Mexico. The water within the legs flows through the Potomac watershed and eventually to the Chesapeake Bay.


The Potomac River, Our National River, has been used and abused since colonial times. The North Branch of the Potomac begins in the West Virginia Highlands as a small trickle at a spring near the Fairfax Stone and then delineates the Maryland/West Virginia boundary until Harpers Ferry where it then divides Maryland from Virginia. Widening and picking up speed it flows 382 miles before ending in the Chesapeake Bay at Point Lookout State Park, Scotland, Maryland. The upper North Branch Potomac watershed covers approximately 230 square miles, with the Stony River watershed draining 59 square miles and each of the other subwatersheds draining around 42 square miles. The watershed is predominantly rural.

 In terms of volume, there are two major tributaries to the North Branch Potomac: Abram Creek and Stony River, both located in West Virginia. Numerous smaller tributaries are also of particular interest, Including Elk Run and Buffalo Creek in West Virginia and Lostland Run and Laurel Run in Maryland. There are two large man‐made lakes in the Stony River watershed. The larger, 1,200‐acre Mt. Storm Lake was built in the early 1960s to serve as a cooling pond for the 1,600‐megawatt coal‐fired Mt. Storm Power Station. The lake is a popular destination for tourists and locals, who boat, fish, and swim in its artificially warm waters. Upstream and to the south, the Stony River Reservoir was created by the West Virginia Paper Company. The Stony River Reservoir is currently drained. This has been done periodically over the years due to structural weakness of the dam. On the North Branch Potomac itself, downstream from Kitzmiller, the Jennings Randolph Reservoir serves as an emergency reservoir for Washington, DC.