The Anacostia River begins as a series of seeps and springs in eastern Montgomery and northern Prince George’s Counties, Maryland. The various springs become a web of small streams that flow generally south, joining with one another to eventually form the river’s two major tributaries, the Northwest Branch and the Northeast Branch. These in turn join to create the mainstem Anacostia just above Bladensburg. The mainstem Anacostia, influenced by Potomac tides as high as 44 inches, slowly flows (“sloshes” may be a more appropriate image) 8.4 miles through the eastern District of Columbia to its confluence with the Potomac (and the Washington Channel) just below Buzzards Point. The Anacostia watershed encompasses 176 square miles, approximately half of which lies in Prince George’s County, one-third of which lies in Montgomery County, and one-sixth of which lies in the District. More than 800,000 people live within the watershed, at an average density of approximately 4600 persons per square mile. Tens of thousands more travel each day – mostly by automobile – into the watershed to work. As a result, well over half of the watershed is given over to residential, commercial, and industrial land uses, and water quality is highly affected by erosion, contaminated runoff, sewage, and illegal dumping.

Physically, the Anacostia is a river of contrasts. Although its watershed is very highly urbanized, most of its banks are protected by parkland or other greenspace. Thus, surprisingly, throughout much of the upper watershed and as far downriver as RFK Stadium, paddlers and hikers can enjoy a quiet, bucolic river that seems curiously out of place in a metropolitan environment. However, from the low CSX Railroad trestle bridge to the confluence with the Potomac, the Anacostia changes character dramatically, pulsating with car and boat traffic and the tumult of industrial activity.

Similarly, the state of the Anacostia’s complex biological web varies greatly from north to south. Healthy and balanced biological systems can still be found in the extreme upper watershed, where large-scale effects of urban life have not yet reached the water. Near the river’s confluence with the Potomac, multiple kinds of contamination from the lives of nearly a million people create a hostile and frequently fatal environment for macroinvertebrates, fish, plants and animals.