This section, the Upper DC Anacostia, had the worst scores for fecal bacteria and Secchi disk depth of all three sections. Overall, the water clarity (Secchi disk depth) is the worst in this section every year. (See trend analysis for Water Clarity for detail.) This is likely because the most upstream section (MD Anacostia) receives clear water during dry weather that dilutes the turbid water of the tidal river while the most downstream section (Lower DC Anacostia) is washed with the cleaner Potomac River water twice a day by tidal action. As a result, the middle section (Upper DC Anacostia) is left the cloudiest.
Both DC sections of the river are subject to Combined Sewer Overflows (CSOs). In much of the older part of the city (see map at right, click to enlarge), stormwater runoff and sanitary sewage are carried in the same system of pipes. As the city has grown, the system has become inadequate to deal with all of the flow that it receives. Rain events above a certain amount overwhelm the system’s capacity and, to prevent sewage from backing up into homes, relief valves are opened that discharge sewage directly to the Anacostia River.
DC Water (formerly DC WASA) broke ground in October 2011 on the $2.6 billion Clean Rivers Project (CSO Long Term Control Plan) to control combined sewer overflows. Scheduled for completion in 2018, the Anacostia River will benefit from the project with a 98% overflow reduction. As a result both DC sections will see significant water quality improvement and AWS's State of the Anacostia River report will detect the change.
Currently however, at the most southern end of this section there is a large Combined Sewer Outfall that discharges the largest amount of sewage -- about 57% of sewage overflow to the Anacostia is discharged from this outfall. See the table to assess the computed CSO overflow predictions and the maps for the outfall locations. (Click on the image to enlarge.)
Click here to download a printable version of the 2011 State of the Anacostia River.
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