[1] Completed by the United States Army Corps of Engineers in 1989, it is meant to prevent sediment from the 1980 eruption of Mount St. Helens from increasing flood risks along the Toutle and Cowlitz rivers.

However, additional debris flows from Mount St. Helens plus sediment from storm-related riverbank failures quickly filled the basin.

[1] In July 2012, the Corps awarded a $4.5 million contract to LKE Corporation of Washougal, to raise the spillway by 7 feet (2.1 m).

[2] In 2013, the contractor raised the dam's spillway by 7 feet (2.1 m) to increase the ability of the SRS to trap sediment.

Large communities downstream of the SRS include Castle Rock, Kelso, and Longview.