Watershed Information

Potomac River Watershed 

Map source: Karl Musser
Map source: Karl Musser

FAST FACTS
Geological Regions:
Appalachian Plateau, Ridge & Valley, Blue Ridge, Piedmont, Coastal Plain
River Miles: Main Stem: 383 (616 km); Main stem plus major tributaries: 12,878.8; 21st largest river in the USA
Discharge: Average flow is 10,800 ft³/s (306 m³/s)
Water Use: 486 million gallons per day or 21 m³/s (ICPRB, 2000) The Potomac River supplies almost 90% of the drinking water to the DC metro area.
Major Tributaries: North Branch, Savage River, South Branch, Cacapon, Shenandoah, Antietam Creek, Monocacy River, Anacostia River
Land Mass: 14,670 square miles. Land Use: 55% forested, 28% agriculture, 5% water and wetlands, 9.7% developed, 2.3% other
Population: 5.8 million (2005 estimated Census) in watershed; 395.4 persons per square mile (8,435 persons per square mile in Washington D.C.)

The Potomac River Watershed covers around 14,670 square miles. The watershed spans 383 miles across several geological regions including the Appalachian Plateau, Ridge & Valleys, Blue Ridge, Piedmont, and Coastal Plain. The main stem plus all major tributaries totals 12,878.8 river miles making the Potomac the 21st largest river in the United States. The river boasts an average daily flow of 10,800 ft³/s. The main tributaries of the Potomac River are North Branch, Savage River, South Branch, Cacapon, Shenandoah, Antietam Creek, Monocacy River, and Anacostia River. The Potomac empties into the Chesapeake Bay downstream. The basin is home to 5.8 million rural and urban residents giving the region an average population density of 395.4 persons per square mile and 8,435 persons per square mile in Washington D.C. About 9.7% of the watershed’s land cover is developed, 55% is forested and 28% is agriculture and only 5% is water and wetlands.
 
Source: Interstate Commission on the Potomac River Basin (http://www.potomacriver.org/cms/index.php?option=com_content&view=article&id=70&Itemid=57)

 

Watershed Photo

 

Image source: NASA (Landsat)
Image source: NASA (Landsat)

 

More maps:

http://www.potomacriver.org/cms/wp-content/uploads/2013/12/maps_images/Potomac_and_Bay_Watershed.pdf

http://www.potomacriver.org/cms/wp-content/uploads/2013/12/maps_images/LandUse.pdf

Anacostia River Watershed

Map source
Map source

Map source:
Map source:

FAST FACTS
River Miles: 8.4 (13.5 km)
Discharge: Average flow is 138 ft³/s.
Major Tributaries: Watts Branch, Lower Beaverdam Creek and Hickory Run.
Land Mass: 176 square miles; Land Use: 64% developed, 29% forested, 4.5% agriculture, 1% water and wetlands, 1.5% other
Population: 800,000 (2005 estimated Census) in watershed; 4,545.5 persons per square mile

The Anacostia River Watershed, located in Maryland and east Washington, D.C., covers around 176 square miles. The main branch is relatively short, only 8.4 miles long, and has an average daily flow of 138 ft³/s. The main tributaries of the Anacostia River are Watts Branch, Lower Beaverdam Creek and Hickory Run. The Anacostia River joins the Potomac River at Buzzard Point. The basin is home to 800,000 urban residents with the majority of the population from Wards 7 and 8 in D.C. The watershed has an average population density of more than 4,500 persons per square mile. About 64% of the watershed’s land cover is developed, 29% is forested and 4.5% is agriculture and only 1% is water and wetlands. Heavy development along the Anacostia River and a lack of concern for the watershed has led to pollution and poor water quality over the years. The channelization of the riverbanks and the loss of wetlands dramatically increase the non-point source pollution, leading to further degradation. According to the Anacostia Watershed Society (AWS), Washington’s sewer system dumps over 2 billion gallons of raw sewage and storm water directly into the river. In addition the National Oceanic and Atmospheric Administration (NOAA) report that more than 20,000 tons of trash and debris enter the Anacostia’s waters each year. However, recently many organizations and local residents have teamed up to protect and restore the Anacostia River.

Source: Anacostia Watershed Restoration Partnership (http://www.anacostia.net/index.html)  

Additional map: http://ddoe.dc.gov/ddoe/frames.asp?doc=/ddoe/lib/ddoe/wqd/tmdl_reports/anacostia/AnacostiaMap.pdf