Video: Mount St. Helens Grade Building Structures Pilot Project
The Mount St. Helens Grade Building Structures Pilot Project is designed to trap sand flowing from the Mount St. Helens volcano and keep it out of the Cowlitz River system. The wooden structures are built in the sediment plain above the Sediment Retention Structure and can be seen from viewing areas near the SRS and Hoffstadt Bluffs Visitors Center. Solar-powered cameras mounted at the site record images of the site every 15 minutes as the North Fork Toutle River flows through the structures. The cameras are able to record major weather events and river flow conditions that the team would otherwise have no way to observe and allow engineers to monitor the structures’ effectiveness from Portland District headquarters, more than 70 miles away. Members of the Mount St. Helens project team also visit the site periodically to evaluate the conditions and determine if the structures are working as designed. These on-the-ground site visits are also important for assessing how these structures impact fish passage upstream and downstream. The Corps believes this pilot project will provide the data necessary to determine if the structures could be an effective component of the Corps’ strategy to manage the sediment, to maintain flood damage reduction benefits for the communities of Longview, Kelso, Castle Rock and Lexington. Available in high definition.