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Largest Construction Project in DC Since Building of Metro

Anacostia River projects overview and tunnel alignment.

The District of Columbia Water and Sewer Authority (DC Water) broke ground in October 2011 on its largest construction project ever, and the District’s largest since Metro was built. The $2.6 billion Clean Rivers Project aims to nearly eliminate combined sewer overflows to the Anacostia and Potomac rivers and Rock Creek, also improving the health of the Chesapeake Bay.


Massive machinery like this will be used to tunnel along, and under, the Anacostia River.

As in many older cities, about one-third of the District has a combined sewer system. A combined sewer overflow (or CSO) occurs during heavy rain when the mixture of sewage and stormwater cannot fit in the sewer pipes and overflows to the nearest water body. CSOs direct about 2.5 billion gallons of combined sewage into the Anacostia and Potomac rivers and Rock Creek in an average year. CSOs contain bacteria and trash that can be harmful to the environment.


The 23-foot diameter tunnels that will store combined sewer overflows will be similar to this one.

The Clean Rivers Project consists of massive underground tunnels to store the combined sewage during rain events, releasing it to the Blue Plains Advanced Wastewater Treatment Plant after the storms subside.


Blue Plains Advanced Wastewater Treatment Plant is the largest advanced wastewater treatment plant in the world.

The first tunnel system, and the largest, will serve the Anacostia River. The first part of that system, named the Blue Plains Tunnel, is 23 feet in diameter and runs more than 100 feet deep. It will extend from Blue Plains in Southwest DC, roughly along the east bank of the Potomac, crossing under the Anacostia and extending along the west bank to about RFK Stadium.


DC Water, Officials Break Ground on $2.6 Billion Clean Rivers Project

Since the early 1900s, only sewer systems with separate pipes (for sewage and stormwater) have been installed in the District. The Clean Rivers Project is the result of a 2005 federal consent decree. DC Water is beginning discussions with the parties on reopening the agreement. The goal would be to explore green-development technologies that could reduce or eliminate future pieces of the project, create jobs, green the District and reduce rate increases for customers. (DC Water)