About the Mattawoman

A Remarkable Resource at Risk

Why do so many care so deeply about conserving special waters like the Mattawoman? If you've been there you know. If not, you may want to check out these 3-minute testimonials from a scientist and from an avid bass angler delivered at two different public hearings on Charles County's comprehensive land-use plan.

Mattawoman Creek comprises a 22-mile long coastal-plain river and seven-mile long freshwater-tidal estuary flowing into the Potomac River about 22 miles south of the nation’s capital.  Once termed “where one goes pleasantly” in the Algonquian tongue [1], its location until the latter part of the twentieth century afforded some protection from the urbanization spreading from Washington D.C.  In 1992, for example, Maryland fisheries biologists were able to say that “Mattawoman Creek represents as near to ideal conditions as can be found in the northern Chesapeake Bay, and should be protected from overdevelopment.” [2]

 Twenty years later, these same scientists concluded that “planned levels of development…should be reconsidered in light of the extent of declines in the fish community.” [2]  And American Rivers declared Mattawoman the nation’s fourth most endangered river for 2009.  In 2011, a state and federal Task Force underscored Mattawoman’s plight by finding that “designation of most of the watershed as a development district virtually assures continuing and dramatic watershed ecosystem deterioration.” [4]

 Many of Mattawoman’s problems originate in the three fourths of the 94-square-mile watershed that lies in Charles County, which promotes bedroom communities sprawling south of its northern county-line, nearest the District of Columbia.  A portion of this county line is formed by Mattawoman’s non-tidal river.

 However, despite the rampant conversion of forest to urbanization, the watershed harbors hotspots of biodiversity [5] for uncommon amphibians, reptiles, and birds, including Maryland’s best coastal-plain site for amphibians and reptiles [6], and two Audubon Important Bird Areas. [7, 8] The river itself is especially notable for its riparian swamps, fish and mussel species, and as a spawning ground for declining migratory fish. The river, and its watershed, feed the estuary described by state and federal scientists “as what a restored Chesapeake Bay would look like.” [4]

 The tidal-freshwater estuary supports some of region’s finest tidal-freshwater marshes—including Maryland’s only western-shore site harboring the American Lotus—and extensive beds of submerged aquatic vegetation.  Unusual concentrations of waterfowl breed and feed here.  These attractions, combined with significant shoreline preservation as state “Wildlands,” make the estuary a relaxing mecca for kayakers, canoers and anglers.

 The estuary also represents a focus for Largemouth Bass anglers, with most of the region’s fishing tournaments launched from Smallwood State Park.  Its mouth at the tidal Potomac River occurs near the boundary between brackish and freshwater, which historically has made the estuary and river an outstanding nursery for anadromous fish that must spawn in freshwater after migrating from their home in the Atlantic Ocean or Chesapeake Bay. The health and abundance of the fish community prompted fisheries biologists to declare Mattawoman “the best, most productive tributary to the Chesapeake Bay” in 2005. [9]

 Since that time, and despite the widespread acclaim and pride in Mattawoman’s remarkable offerings, analyses by fisheries biologists now find that the health of Mattawoman has begun to decline at an alarming rate as its watershed passes a well-known threshold for too much urbanization, measured by the amount of pavement, roads and rooftops known as “impervious surface.” [3]  In fact, the Task Force noted above emphasizes that “the future of the Mattawoman watershed is at a turning point.” [4]

 Today, on this side of the turning point, the watershed remains mostly forested. These forests retain remarkable biodiversity even as they filter water to sustain the vibrant living resources of river and estuary.  Tomorrow, the fate of Mattawoman depends on choices before us:  will we choose to grow wiser to protect one of the Chesapeake Bay’s finest tributaries? Or, will we follow the business-as-usual that is causing Mattawoman, and so many other waterways, to falter?

 Please visit other portions of the website to find out more about the threats to Mattawoman, and what you can do to help!


 [1] The Place Names of Maryland: Their Origin and Meaning, Hamill Kenny. Maryland Historical Society, Baltimore, MD. (1984).

 [2] Fish sampling in eight Chesapeake Bay tributaries, MD Dept. Natural Resources, Report CBRM-HI-92-2 (1992) http://www.dnr.state.md.us/irc/docs/00000757.pdf

 [3] Chesapeake Bay Finfish/Habitat Investigations, Project  3,  Job 1: Fisheries and habitat interactions project: Development of habitat –based reference points for Chesapeake Bay fishes of special concern: Impervious surface as a test case-2009,  MD Dept. Natural Resources, Report F-61-R-5. http://www.dnr.state.md.us/irc/docs/00015592.pdf

 [4] The Case for Protection of the Watershed Resources of Mattawoman Creek:  Recommendations and Management Initiatives to Protect the Mattawoman Ecosystem, The Interagency Mattawoman Ecosystem Management Task Force. Prepared for: Charles County Department of Planning and Growth Management to support the County Comprehensive Plan update. December 2011. Final report March 2012.


 [5] A GAP analysis of animal species distributions in Maryland, Delaware, and New Jersey, Final Report-Part 2. McCorkle, R.C., J.N. Gorham, and D.A. Rasberry. U.S. Fish & Wildlife Service, Delaware Bay Estuary Project, and USGS Biological Resources Division, Gap Analysis Program (2006).


 [6] Maryland Biological Stream Survey, 2000-2004, Vol. 9: Aquatic biodiversity, MD Dept. Natural Resouces, Report CBWP-MANTA-EA-05-6. Download pdf here.

 [6] Chapman State Park Important Bird Area. http://iba.audubon.org/iba/viewSiteProfile.do?siteId=2137&navSite=state

 [8] Mattawoman Important Bird Area, described here.

 [9] What could happen to tidal fish habitat and fisheries in Mattawoman? Lessons learned in Severn River and other developed Bay tributaries, Uphoff, J., Powerpoint presentation to Charles County Commissioners, June 20, 2005.