Washougal firm to lead Toutle River sediment management
More than 30 years after a massive eruption changed the landscape of Mount St. Helens, the U.S. Army Corps of Engineers is taking another approach to manage sediment still finding its way into the North Fork Toutle River and ultimately the Cowlitz River.
The Mount St. Helens Grade Building Structures Pilot Project is expected to slow down the flow of the river and allow sediment to settle on the mountain before it gets into the watershed.
"If they work the way we believe they will, these structures will stop sediment and encourage small islands to form," said Marci Johnson, project coordinator. "Those islands, in turn, will help form habitats which could produce food for wildlife."
LKE Corp., a Washougal-based construction company, was awarded the contract June 10. The project's cost is $3.5 million and is being funded through the American Recovery and Reinvestment Act of 2009 – also known as the federal stimulus program.
"We are very excited. This is a one-of-a-kind project," said Mike Walsh, project manager at LKE Corp.
Construction on the pilot project began this month in the sediment plain above the Sediment Retention Structure (SRS), which means a popular area for visitors to Mount St. Helens will be off limits.
"Hikers will not be allowed in and around the staging and construction areas," Johnson said. "People will be able to see the construction from viewing areas near the SRS and Hoffstadt Bluffs Visitors Center."
The eruption of Mount St. Helens on May 18, 1980 dramatically altered the Cowlitz and Toutle River valleys, with ash fall and the lateral blast from the eruption causing immediate and long-term effects on the hydrology of the watershed by changing its land cover and runoff characteristics. About 170 million tons of sediment made its way into the Toutle, Cowlitz and Columbia rivers from 1980 to 1990.
Interim measures have been implemented to reduce flood risk on the Cowlitz River while the long-term plan is developed, including the dredging of the mouth of the Cowlitz River in 2007, 2008 and 2009.
According to LKE's website, the company was founded in 1993, with much of its work focused on environmental projects, including enhancement of watersheds, restoration of wildlife and fish habitat, as well as new development such as the construction of freeways and subdivisions.
