Lake Washington Ship Canal Lake Washington Ship Canal The Lake Washington Ship Canal, which runs through the city of Seattle, connects the fresh water body of Lake Washington with the salt water inland sea of Puget Sound. The Hiram M. Chittenden Locks accommodate the approximately difference in water level between Lake Washington and the sound. The canal runs east–west and connects Union Bay, the Montlake Cut, Portage Bay, Lake Union, the Fremont Cut, Salmon Bay, and Shilshole Bay, which is part of the sound. The ship canal project began in 1911 and was officially completed in 1934. Prior to construction of the Lake Washington
Puget Sound the ice sheets had retreated. Because the rate of rebound was not synchronous with the post-ice age rise in sea levels, the bed of what is Puget Sound, filled alternately with fresh and with sea water. The upper level of the lake-sediment Lawton Clay now lies about above sea level. The Puget Sound system consists of four deep basins connected by shallower sills. The four basins are Hood Canal, west of the Kitsap Peninsula, Whidbey Basin, east of Whidbey Island, South Sound, south of the Tacoma Narrows, and the Main Basin, which is further subdivided into Admiralty Inlet and the