Water Quality Conditions
At elevated levels, two nutrients, phosphorus and nitrogen, can negatively impact freshwater ecosystems. By triggering algal blooms, which eventually reduce the dissolved oxygen (DO) level of the water, nutrient pollution can kill fish and other aquatic life. Nutrients can originate at either point sources (i.e., well-defined sources such as factories and sewage treatment plants) or nonpoint sources (i.e., diffuse sources such as lawns, septic systems, farms, and the atmosphere). Typical sources of phosphorus and nitrogen include fertilizers, animal wastes, automotive exhaust, organic material, soil, etc.

Uncontrolled stormwater runoff leads to accelerated streambank and streambed erosion and the release of sediment. The fine sediments released in this process, including sand, silt, and clay impair river and stream habitat. They also reduce water clarity and clog the gills of many aquatic organisms. The monitoring of Total Suspended Sediment (TSS) loads provides an indication of the severity of erosion in a wateshed. The high level of imperviousness (i.e., surfaces through which stormwater runoff does not penetrate) in the Anacostia watershed along with an inadequate number of stormwater management controls and outdated sanitary sewer and combined sewer systems all contribute to the problem.

Click on the following links for tidal Anacostia River water quality graphs.

The Nitrogen Load to the Tidal Anacostia River is estimated to be approximately 7,945 lbs/square mile/year. The average nitrogen loading rate among the 10 Anacostia subwatersheds with known loadings is 5,696 lbs/square mile/year. A completely forested watershed would be expected to generate approximately 42 lbs/year/square mile.

The Phosphorus Load to the Tidal Anacostia River is estimated to be approximately 1,813 lbs/square mile/year. The average nitrogen loading rate among the 10 Anacostia subwatersheds with known loadings is 785 lbs/square mile/year. A completely forested watershed would be expected to generate approximately 8.2 lbs/year/square mile.

The TSS Load to Tidal Anacostia River is estimated to be approximately 279 lbs/year/square mile. The average Anacostia subwatershed nitrogen load is 347 lbs/square mile/year.

DO Levels

The data reported here reflect both grab sampling and modeling results. It is important to note, however, that water quality monitoring in the Anacostia tributaries has been discontinued and that these results are not current. It is anticipated that the these water quality results will be updated as additional data become available.