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To produce the results above, water quality data was analyzed for three sections of the tidal Anacostia River: the Maryland portion of the Anacostia (MD Anacostia), the upper half portion of the Anacostia in Washington, DC (Upper DC Anacostia), and the lower portion of the Anacostia in the District (Lower DC Anacostia). As depicted in the chart above, all three sections earned F grades. On average, the percent score for the entire Anacostia was 42 percent.
Due to the many factors that affect water quality there are limitations to the annual comparison of water quality data. For example, more intense and frequent precipitation patterns generally make the water quality worse. And comparing annual data for wet and dry years may NOT give us a better understanding of the river and the watershed. Long term trends are much more helpful for understanding changes in water quality.
In 2012, there were fewer intense rainfall events resulting in less torrential stream flows in the tributaries of the Anacostia. As a result some parameters improved while others became worse compared to the previous year. Dissolved Oxygen (DO), for example, became worse in 2012 compared to 2011 because less oxygen rich stream flow entered into the tidal Anacostia.
Fewer peak stream events usually mean less fecal matter input to the river, however it increased here in 2021. Less sediment particles poured into the tidal Anacostia in 2012 giving more time for the particles to settle out, and was likely the cause for the better Water Clarity score that year. The score of chlorophyll (a) (related to algae growth) remained the same. SAV had disappeared in 2003 and has not yet come back. However, the discovery of a seedling in Kingman Lake by AWS raises the possibility for SAV to again grow in the Anacostia. There was no significant progress on Toxics or Trash from 2012 to 2013.