Sediment Retention Structure is an earthen dam , long and high , on the North Fork Toutle River in the U.S. state of Washington . 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
1980 eruption of Mount St. Helens
1980 eruption of Mount St. Helens
Toutle River Sediment Retention Structure