Examination of Fecal Indicator Bacteria in the NE Branch of the Anacostia River

The Anacostia River is a crucial stream ecosystem in Maryland and Washington D.C. and is a tributary to the Potomac River which flows into the Chesapeake Bay. However, it is also an extremely degraded ecosystem due primarily to the urbanization of the watershed. One of the major problems affecting all portions of the Anacostia River is the presence of fecal indicator bacteria, including fecal coliforms and E. coli. The tidal portion the Anacostia has high levels of bacteria due mostly to combined sewer systems (sanitary and storm water running through one pipe) in D.C. that overflow into the stream during rain events. The Maryland portion of the stream does not have combined sewers but it still has high values of fecal indicator bacteria. I propose to examine the fecal indicator bacteria loads in the North East Branch of the Anacostia River and its tributaries in order to determine the sources. The first step in doing this would be to sample for baseline conditions in the stream systems. This would involve sampling during extended periods of dry weather to determine if there are any bacteria already in the stream that are not coming from a storm event. After baseline sampling is concluded, event based sampling would occur for various magnitude rain events, to determine if any rain event would produce high bacteria levels. The ability to sample water coming off the land (possibly from the end of a storm water pipe) would be essential for the analysis as well. This will allow us to determine if there is something contributing to the bacteria load other than overland flow(flow coming from the terrestrial ecosystem), like a break in a sewer line. After the sampling is concluded the data would be compared with the data collected from my current thesis project on sediment and overland flow for the watershed. The goal of the project would be to characterize the bacteria patterns and flow paths for the watershed.

Figure 1. The North East Branch of the Anacostia Watershed with potential locations for sampling to occur.