Before construction of the Lake Washington Ship Canal in 1916, Lake Washington's outlet was the Black River[?], which joined the Duwamish River and emptied into Elliott Bay[?]. When the canal was opened, the level of the lake dropped nearly nine feet. The canal to Puget Sound became the lake's sole outlet, causing the Black River to dry up and disappear, as a few years earlier, the Cedar River had been diverted to empty into Lake Washington instead of the Black.