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Total Area: 11,850.2 acres (18.5 Square miles) Average Imperviousness: 42% Population: No Data (1990 Census) Population Density: No Data   Forest Cover No Data Acres Deciduous: No Data Coniferous: No Data Mixed: No Data Shrub/Scrub: No Data Undefined: No Data Wetland Cover No Data Acres Emergent: No Data Forested: No Data Open Water: No Data Shrub/Scrub: No Data

The Tidal Anacostia River is formed by two major tributaries, the Northwest and Northeast Branches. Downstream of the confluence of these two streams, the Anacostia is a channelized, freshwater tidal river, which flows approximately 8.4 miles before joining the Potomac River. The Tidal Anacostia River drainage area is located in both Prince George's County and the District of Columbia.

Dominant Land Uses: The two dominant land uses in the The Tidal Anacostia River drainage are residential (32%) and parks (21%).

Physical Characteristics: Flow in the tidal river portion may be described as sluggish with an average water residence time on the order of 30 to 35 days. Average daily inflow into the tidal river is approximately 138 cubic feet per second (i.e., 61,934 gallons per minute). The Tidal Anacostia River drainage area is 11,850.2 acres (18.5 mi2) in size and approximately 42% impervious. The Tidal Anacostia River, which is contained wholly within the Coastal Plain physiographic province, has an average mainstem gradient of 0.22%.

Biological Characteristics: The District of Columbia has designated the Tidal Anacostia River as Class B,C,D, and E waters (MDE, Use I). An analysis of biological conditions in the tidal portion of the Anacostia River is currently underway.

Condition Summary:
The tidal Anacostia River suffers from overall poor water quality due to the factors that plague many urban rivers. Due to intense development, a high percentage of impervious surface and high stormwater runoff volumes, it receives large amounts of pollutants including sediment, excess nutrients, toxics, trash, and debris. Additionally, with almost every significant rainfall event, it receives sewage and other pollutants from combined sewer and stormwater overflows, which discharge directly into the river. Many of these factors contribute to both chronically low dissolved oxygen levels that frequently violate water quality standards and threaten aquatic life and high bacterial levels which make water contact activities (such as swimming and wading) unsafe.

To get involved in protecting the tidal Anacostia River contact The Anacostia Watershed Society.

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