North Fork Toutle River, Sediment Retention Struct., Mount St. Helens

The May 18, 1980 eruption of Mount St. Helens had a dramatic impact on the North Fork Toutle River. The debris avalanche, lateral blast and ashfall produced a substantial amount of sediment, which continues to be washed into the river and transported downstream. A Sediment Retention Structure was constructed (out of view) to minimize the amount of sediment flowing downstream. View is to the east with Mount St. Helens in the background.