Update: People will be able to legally take a swim in the Anacostia River for the first time in decades, during a “splash day” on Sept. 23. The free swim event was supposed to take place on July 8 at Kingman Island, but was rescheduled after heavy rains and sewer construction work caused overflows of untreated sewage into the river.

People who were previously registered for the sold-out event can register now. It will open up to the general public again on Sept. 7 at 9 a.m.

Organizers chose the late September date because the DC Water construction that caused overflows in July is scheduled to be complete by then. In addition, the water should still be warm enough for an enjoyable swim.

Meanwhile, organizers are already thinking about next summer — they say they’ll try to schedule a swim day earlier in the summer, to hopefully avoid heavy rainfall, which can contaminate the water. And they’re considering ways to expand the event, perhaps holding a longer-distance swim in the river, for open water swimmers. They’re also hoping to hold multiple swim events at different locations along the river, to give more people the chance to jump in.

In water quality testing last year, three Anacostia River locations passed recreational water standards more than 90% of the time: Kingman Island, Buzzard Point, and Washington Channel.

Original story:

The Anacostia River is much cleaner than it’s been in many decades — but don’t put on your swimsuit just yet. A permitted event allowing people to swim in the river for the first time in more than 50 years has been postponed after heavy rain this week, and infrastructure work put a key sewage tunnel offline.

“It really is just unfortunate timing that has led to this,” says Quinn Molner, with Anacostia Riverkeeper, the nonprofit organizing the swim event. “But we are closer now than ever to a swimmable Anacostia River, and that’s from decades of work that’s been happening on the river, both in the government and nonprofit sectors.”

The event was scheduled for Saturday, July 8 at Kingman Island. It’s being postponed for September.

Many D.C. residents were skeptical — after all, the Anacostia River has a reputation for being one of the most polluted urban rivers in the country. Still, the event was highly popular: it was sold-out, with nearly 150 people signing up for free tickets online.

“Those signups went very quickly. Any time tickets were posted, they were gone within the hour,” Molner says.

Water quality testing over the past three years has shown many parts of the Anacostia River and Potomac are clean enough to swim in most of the time. Five locations on the rivers met water quality standards more than 80% of the time.

The weather was one major factor in the cancellation. After an unusually dry spring and early summer, July started with back-to-back thunderstorms. Heavy rains like this can overwhelm D.C.’s century-old sewer system, causing sewage overflows into the rivers. Indeed, there were two such overflows on the Anacostia River on Thursday after heavy storms, dumping millions of gallons of sewage and stormwater into the river.

Another factor was that an important piece of sewer infrastructure was offline this week, allowing more untreated sewage than usual to flow into the Anacostia River. This happened because DC Water is currently connecting its newest sewer tunnel into the system. To do so, the water and sewer authority had to disconnect one of the sewer outfalls near Kingman Island, meaning that in a heavy rain, that outfall would dump into the river, rather than into the sewage system. On Thursday, that disconnected outfall discharged 2 million gallons of sewage and stormwater that would otherwise would have been captured and treated.

The work is part of DC Water’s Clean Rivers Project, a $2.7 billion sewer upgrade to keep pollution out of the District’s waterways. The first major segment went into operation in 2018, and has so far kept 15 billion gallons of sewage out of the Anacostia River, reducing overflows by 92%. That reduction will rise to 98% when the next segment goes online in August or September this year.

The other overflow, of 1.5 million gallons, occurred near Navy Yard, and was not related to any work underway, says DC Water spokesman John Lisle.

“It’s unfortunate that the event was called off,” says Lisle. “It’s really a nice opportunity to highlight the water quality improvements that are taking place on the Anacostia River, and the Clean Rivers Project is certainly part of that.”

When the project is complete, overflows on the Anacostia are expected to reduce from an average of 82 a year to just two.

Molner says DC Water did not inform Anacostia Riverkeeper that the sewer outfall would be out of commission this week.

“We wouldn’t have scheduled it had we known this,” Molner says.

But Lisle says DC Water has been in frequent communication about the work with the District Department of Energy and Environment, which issued the permit for the swim event.

Molner says the event will be rescheduled for after DC Water finishes work interconnecting the new tunnel.

“We’re still going to celebrate this milestone. This is just a tiny setback.”