The Tidal Basin is about 107 acres in size and approximately 10 feet deep. It was built to harness the power of the tides in the Potomac River to flush silt and sediment from the Washington Channel. Fill lands separate the Washington Channel from the Potomac River; the Washington Channel drains into the Anacostia River just above its confluence with the Potomac. Tidal Basin, Washington, DC (U.S. National Park Service)