A break in a major sewer interceptor late Wednesday sent an estimated five million gallons of sewage spilling across the Capital Crescent Trail and into the Potomac River, according to DC Water. The trail will remain closed as DC Water repairs the break, which could take a week or longer.

Interceptor sewers receive sewage flow from multiple smaller trunk sewers. The interceptor that ruptured on Wednesday, the Upper Potomac Interceptor, carries sewage to the city’s wastewater treatment plant at Blue Plains, in the southern tip of the city. The spill from the break, according to a DC Water press release, ran overland, across the trail, and into the Potomac. DC Water dispatched a contractor crew to install a temporary sewage bypass until full repairs are completed. The break occurred during record-setting rainfall that ended yesterday morning.

The Capital Crescent Trail is closed to the public between Fletchers Cove and the end of the trail, at Water Street in Georgetown. DC Water urges everyone to avoid contact with the area.

DC Water also cautions the public to avoid contact with the Potomac for 72 hours, although the agency says this is the case after all heavy rains that cause combined sewer overflows. The ongoing $2.6 billion Clean Rivers Project is aimed at reducing these overflows.

Normally, when sewage levels rise to a certain level in a rainstorm, a dam is designed to deflate and send the combined sewer overflows into the river, says DC Water spokesman John Lisle. But something appears to have malfunctioned on Wednesday, causing breaks in a pipe and sending the sewage across the trail at two locations, both near the intersection of Foxhall Road and Canal Road, just west of Georgetown.

The cleanup effort, says Lisle, is starting today. DC Water is coordinating with the National Park Service to clean both the trail and the adjacent vegetation. The agency is installing physical barriers to keep people off that section of the trail, and personnel will also be present to ensure the no one comes into contact with the contaminated area.

“We’re trying to clean it up as fast as we can, and get it reopened for trail users,” says Lisle.

This post has been updated to include comments from Lisle.

Photo by Flickr user Daniel Lobo