The Salmon Creek drainage basin, containing Salmon Creek and several tributaries, is just under two square miles in size. Much of the current basin once flowed northward toward Longfellow Creek, with the old divide lying between Mallard Lake (Kingston Pond) and Lake Garrett (Hicks Lake). Salmon Creek today meanders for three-fifths of a mile between Ambaum Boulevard, where it spills out of a 48-inch pipe, and Shorewood Dr. Despite encroaching suburbia, Salmon Creek has avoided the severe erosion problems plaguing most urban streams. This is due to an 18-inch, high-flow bypass pipe (an old government sewer line), used since the late 1970s to channel stormwater directly into Puget Sound.
Prior to 1980, high water flows eroded banks and carried large amounts of sediment down Salmon Creek into Puget Sound during large storms. Erosion and blockages in the channel and culverts caused flooding to private property in both the upper and lower stream basin. In 1980, the White Center Drainage Improvement Project resulted in more consistent and less destructive stream flows in Salmon Creek.
Continue on to learn more about the later efforts at developing the area