The Potomac River Stormwater Retention Tunnel is big because the inside diameter must be 18 feet to accommodate the outflow from the river adjacent to the Kennedy Center to the treatment plant in Anacostia. The construction of the tunnel is required under a consent decree between D.C. Water and the federal government. Overflows occur after a storm when a runoff is too great for the sewer, and the diverted flow that contains raw sewage empties into the river.
The Citizens Association of Georgetown has provided extensive comments on the current plan for the tunnel. We are concerned about the possible construction of large diversion structures and associated dropshafts in Georgetown. The drop shaft would be 100 feet deep, and would connect to the tunnel that extended westward along the Georgetown Waterfront Park. The two sites of concern are those in the 2900 block of K Street, and a location near Potomac and Water Streets, or possibly even in the Waterfront Park itself. Our association has objected to any construction within the Waterfront Park.
— Bob vom Eigen