Upper Patuxent River and Reservoirs
Fun Facts

DID YOU KNOW...

• Montgomery County has over 1,500 miles of streams and 1,200 miles of storm drains, which drain over 313,000 acres. These streams flow into four major rivers, the Anacostia, Monocacy, Potomac, and Patuxent, which ultimately discharge to the Chesapeake Bay.

• The Patuxent is the only major river in the Chesapeake Bay watershed with all of its drainage within the state of Maryland. Since the early 1980's, the seven jurisdictions in the Patuxent watershed have worked together on interjurisdictional pollution control projects and management strategies.

• The Montgomery County portion of the watershed represents about six percent of the total Patuxent watershed, including a significant portion of the headwaters to the upper Patuxent River.

• The Upper Patuxent River forms the boundary between Montgomery and Howard counties. Montgomery County's drainage area includes about 46 percent of the Upper Patuxent watershed while Howard County includes about 53 percent. Less than one percent of the drainage area lies within Prince George's and Frederick counties.

• The Upper Patuxent includes the Triadelphia and Rocky Gorge Reservoirs which supply drinking water to about 700,000 residents in Montgomery and Prince Georges counties, and to a small number of residents in Howard County.

• Many of the tributaries to the Upper Patuxent, including the Hawlings River, show signs of physical degradation due to uncontrolled stormwater runoff from suburban and agricultural sources.

• Storm drains from developed areas in the Upper Patuxent watershed are in fact “stream drains” as they carry pollutants directly into streams, which flow into the reservoirs.

• Current rates of sedimentation, nutrient inputs, and dissolved oxygen depletion indicate that the reservoirs are showing signs of stress.

• The Upper Patuxent includes one of the best brown trout put-and-take fishing areas in the county.

• Despite signs of impairment, the Upper Patuxent watershed contains some of the least degraded streams in the county and the riparian forest adjacent to the river is rich and diverse.

• Currently, land use in Montgomery County's portion of the watershed includes 44.5 percent forest and open space. If development continues as in the past, the forested land use will be reduced to 29.8 percent. Forest cover is an essential component of watershed conservation providing nutrient filtering, slowing stormwater runoff velocity, and moderating the effects of heated runoff form summer showers.

For more information on what you can do to help protect the Upper Patuxent watershed, please contact the Montgomery County Department of Environmental Protection at 240.777.7770.