A view of the Washington Monument from below the Tidal Basin Inlet Bridge. (USACE photo by Christopher Fincham) The U.S. Army Corps of Engineers, Baltimore District’s Potomac and Anacostia Rivers Drift Collection and Removal Unit operates out of dock facilities adjacent to the Washington, DC, Navy Yard and conducts drift removal operations on a year-round basis. Their mission also includes the operation and maintenance of the inlet and outlet gates to the tidal basin, which is designed to prevent water stagnating in the tidal basin by allowing fresh water to flow in and out of the basin.