The 7-mile stretch of the Anacostia River Tunnel project that's been completed has surpassed expectations so far, and with more rain in the forecast, it may be put to the test this week.

WASHINGTON — The 7-mile stretch of the Anacostia River Tunnel project that’s been completed has surpassed expectations so far, and with more rain in the forecast, it may be put to the test this week.

John Lisle, chief of marketing and communications for DC Water, said the new Anacostia River tunnel project has proven capable of handling major storms and rain events since opening in March.

“The tunnel itself can hold at any one time, 100 million gallons,” Lisle said.

The tunnel has already surpassed expectations, capturing almost 3 billion gallons of combined sewage.

So far, 88 percent of the combined sewage going into the river has been captured — that’s 8 percent more than projected.

Mining has already begun for the next phase of the project, the Northeast boundary tunnel, a 5-mile tunnel that will connect with the existing tunnel into the center of the city where flooding has been a problem.

Lisle said the section of tunnel that is already open is an important step forward that is already paying off when it comes to economic activity and new construction along the Anacostia.

“It’s great for the city both economically and for the environment so we’re very proud of this tunnel and the way it’s been performing so far.”