Water Quality in the Anacostia River: What the Data Shows

Water Quality in the Anacostia River: What the Data Shows

Getting better data

Last year was the “Year of the Anacostia,” and DC’s best river got a lot of new attention. With big projects like the Anacostia River Tunnel making huge positive impacts on the river’s health, headlines started saying things like “Coming Soon to D.C.: Rivers Clean Enough for Swimming.”

Water quality specialists at the District Department of Energy and Environment (DOEE) have been measuring water quality in the Anacostia and Potomac Rivers for years, but the agency recognized a need to prepare for increased interested in measuring the progress of the river. Given the more than $1 billion price tag of the tunnel projects that will mitigate sewer overflows in the District, many groups are interested to see what kind of impact the new infrastructure has on E. coli, a contaminant that enters rivers primarily from sewage.

In June, DOEE awarded a new grant to the Anacostia Riverkeeper, a local nonprofit organization, to assist them in this effort by establishing a volunteer water quality monitoring program. Riverkeeper already takes certain water quality measurements and publicizes them through an app and website called Swim Guide, which helps users find places that are safe for swimming. Starting this May, the organization will be ready to test water quality much more frequently.

Is it getting better?  

DOEE has measured water quality in the upper and lower segments of the Anacostia River for several indicators, including the big three that are included in the Environmental Protection Agency’s standards for swimming: E. coli, pH, and turbidity.

E. coli is a bacteria that can be found in waters contaminated by sewage (and other sources like dog poop). pH is a measurement of acidity, and turbidity is a measurement of water clarity and cloudiness.

The District has adopted EPA’s Class A Water Quality Standards.

The District has adopted EPA’s Class A Water Quality Standards.

Between 2011 and 2015, DOEE found that the upper segment of the river had the most frequency of falling below safety standards due to E. coli, with around 37% of the tests failing. However, there were many tests in which the water passed each of the safety standards.

2011-2015 DOEE Data Table.jpg

Last year, the Anacostia Riverkeeper started testing water quality in the Anacostia every other week between May and September at several locations.

Ambient Monitoring Stations ANA.jpg

The rain didn’t help

Unfortunately, 2018 turned out to be the wettest year on record for the District, which was not great for the health of the river. WAMU 88.5 reported, “The Anacostia River was supposed to get a lot cleaner this past summer, after DC Water completed a major new sewer tunnel. But water testing shows bacteria counts were, in some cases, higher in the summer of 2018 compared to 2017. What happened? The short answer: rain. Lots and lots of rain.”

During all of the constant, heavy rainfall, excess sewage from our historic combined stormwater and sewer system flushed into the river. Despite the capacity of the new tunnels to capture around 89% of the sewage that would have gone into the river this past year, the volume of rainwater was so high that the impact was still severe. DOEE recorded few days that E. coli was lower than the standards, although pH and turbidity suffered less.

Nevertheless, there were still days in 2018 when the river technically surpassed the EPA’s Class A water quality standards for swimming. Anacostia Riverkeeper tested for E. coli at several sites every two weeks from April and September in 2018, and nearly every location got a green light for swimming by that metric on more than one occasion.

data graphs-04.jpg

As long as 2019 isn’t as precipitous as last year, we should see even more passing days this year. When DC Water’s tunnel project completes its last leg in 2023, which will capture a projected 98% of sewage overflow into the Anacostia, we may see a whole lot of days when the river will be safe for swimming.

The Anacostia River Pool initiative is preparing for those days. While it is currently illegal to swim in the river outside of permitted events, and while there are still challenges to be overcome to achieve better water quality and cleaner sediments, we are headed in the right direction.

We want to look forward to the day we get to jump in the Anacostia River, so we are investigating what a swimming facility might look like along its shores. Want to learn more? Read the feasibility study that was completed in 2018.


Erin Garnaas-Holmes is the Ambassador to the Anacostia Watershed Urban Waters Partnership.

Swimming Links

Swimming Links