1st Annual Swimmable Potomac Report Issued by PRKN


Identifies Where and When The Potomac is Safe For Human Contact

Washington, D.C. – July 23 – Potomac Riverkeeper Network (PRKN) today released its first annual Water Quality Monitoring Report for the Potomac River, which analyzes the data and results of water sampling at 10 sites along the Potomac River in 2019, including data for testing results to date in 2020. The data, collected and analyzed by its team of volunteer community scientists as part of the organization’s Swimmable Potomac Campaign, demonstrates that public health standards at those sites were met only half the time.

Dean Naujoks, Potomac Riverkeeper, said, “Our basic findings show that there is far too much bacteria in the river near Combined Sewer Overflow (CSO) discharge pipes which poses a public health risk. Our data shows river bacteria levels and overall water quality improves as we move downriver from CSO’s. Yet, thousands of people enjoy on-the-water recreation, boating, kayaking and swimming often where water quality is not good. After a rain event it is not a good time to go on the river but on a positive note we have plenty of days where it is safe to swim in the Potomac which is why we are encouraging people to download SwimGuide so people know when and where the river is safe for human contact.”

From May through October, dozens of volunteer community scientists, trained by Potomac Riverkeeper Network, collect and analyze water samples from the Potomac River. PRKN recently expanded its citizen science program from Fletchers Cove down to Mallows Bay, the new National Marine Sanctuary. In 2019, the 200 water monitoring samples collected from 10 sites showed E. coli bacteria met public health standards 55.8% of the time. 2020 data collected at the same ten sampling sites is showing similar results but the addition of four new sampling sites downriver demonstrates water quality vastly improves downriver below Woodrow Wilson Bridge. PRKN’s sampling of the Potomac in the District of Columbia is funded by the District Department of Energy and Environment, under a project to sample the Potomac and Anacostia Rivers and Rock Creek in the District. Anacostia Riverkeeper is the project lead.

The systems and protocols established for the citizen science program in DC as well in Maryland and Virginia waters meet the highest standards of accuracy and veracity so that governmental authorities can be assured of reliability when using the information to make informed decisions about water quality improvements. Last year, Virginia Department of Environmental Quality (DEQ) certified PRKN’s floating laboratory located at National Harbor as a Tier III Certified Lab.

The Tidal Basin collection site was the cleanest location, which appears to be shielded from combined sewer overflows and urban stormwater runoff, passing the E. coli bacteria test 90% of the time. The National Harbor collection site was a close second with an 85% passing rate but the new sampling sites downriver at Little Hunting Creek, Pohick Bay and Mallows Bay are consistently meeting water quality standards that are safe for human contact.

At the other end of the scale, Battery Kemble Creek was the most frequently E. coli contaminated site regardless of rain effects as the location passed testing only 5% of the time. Foundry Branch performed only slightly better with a 10% pass rate. Other Potomac sites, Washington Canoe Club, Thompson Boat House and Oronoco Bay consistently failed to meet water quality standards. All are located within close proximity of DC’s or Alexandria’s CSO discharge pipes.

“Our sampling shows we have poor water quality far too often at places along the river where we see the greatest concentration of recreational users. Our goal is to make the Potomac River swimmable again. We want people to use the river but we want people to do it safely. We are still ten years away from DC completing its Clean Rivers Project and five years from Alexandria completing its CSO fixes. In the meantime, people need to know when and where the river is safe for human contact,” Naujoks said.

The results also showed a direct correlation between high turbidity levels and high bacterial levels. Basically, measurable rainfall in three days prior to testing significantly increased the probability of E. coli test failure. Rainfall triggers both combined sewer overflows and stormwater pollution.

Naujoks continued, “As we celebrate the 20th Anniversary of Potomac Riverkeeper this year, we are expanding our Swimmable Potomac Campaign by adding additional sampling sites, asking that DC and Alexandria stay on track to complete the CSO tunnel projects and that DC lift this archaic law that prohibits people from swimming in the Potomac River, which is a public resource. We are the only city in the country that prohibits swimming as a result of raw sewage! This river belongs to the people.”



About Potomac Riverkeeper Network

Potomac Riverkeeper Network is a registered 501(c)3 non-profit organization with three regional Waterkeeper branches: Potomac Riverkeeper, Upper Potomac Riverkeeper, and Shenandoah Riverkeeper. Our mission is to protect the public’s right to clean water in our rivers and streams. We stop pollution to promote safe drinking water, protect healthy habitats, and enhance public use and enjoyment.