These core parameters were used to analyze water quality for the Anacostia River.
Although some algae is natural, too much depletes water clarity and oxygen. Algal blooms disturb ecosystem balance and can harm human health. While the northern part of the Anacostia scores well, the lower parts appear to be receiving excess nutrient pollution, with algae growth aided by typically slow tidal flows.
Important for survival of fish and wildlife that need sufficient oxygen. Upstream sections scored better thanks to free-flowing tributaries, which mix in more oxygen. Downstream, slow flow and tidal “sloshing” can create problems, but cleaner Potomac River water helps at the mouth of the Anacostia. Near-attainment of DO Water Quality Standards is encouraging, as is the return of Osprey to the River.
Excessive amounts are unnatural and prevent a healthy, swimmable Anacostia. High concentrations come primarily from raw sewage. In DC, Combined Sewer Overflows dump untreated sewage into the Anacostia any time rain exceeds the drains’ capacity. MD is a surprisingly significant source of fecal bacteria, due primarily to sanitary sewer infrastructure damaged by excessive stormwater flows. Both MD and DC are awaiting sufficient infrastructure to address this problem.
We measured secchi disk depth - how far a secchi disk, pictured to the right, can be lowered into the water column until the point it is no longer visible. The Anacostia’s biggest challenge, stormwater pollution, is most visible in the river’s sedimentation, which harms water clarity, or how deep light can travel to reach organisms that need it to survive. Also affects oxygen, as aquatic plants need light for photosynthesis. The Anacostia’s cloudiness comes largely from eroding streambanks, particularly in heavy rains. The River’s worst category: In 2009 the standard was never met in any section. Stricter stormwater regulations are needed, and Montgomery County is leading the way on this change.
Click here to download a printable version of the 2010 State of the Anacostia River.