The District of Columbia has three monster tunnel boring machines doing work beneath the ground as its Clean Rivers Project marks the halfway point in its 20-year plan.The Clean Rivers Project will see the construction of multiple tunnels to capture combined sewer overflows and improve the quality of the Anacostia and Potomac rivers and Rock Creek.“It’s required by federal statutes for us to address the combined sewer overflow problem here in the District of Columbia,” says Clean Rivers Project Director Carlton Ray. “We developed a 20-year plan in 2002 and it was accepted by the U.S. Environmental Protection Agency, the Department
