New approach studied for managing Mount St Helens sediment

Project Updates - June 24, 2010

Thirty years after a massive eruption changed the landscape of Mount St Helens in the US, the US 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 co-ordinator. “Those islands, in turn, will help form habitats which could produce food for wildlife.”

LKE Corporation, a locally-owned small business, was awarded the contract June
10.

The project’s cost is US$3.5 million and is being funded through the American
Recovery and Reinvestment Act of 2009.

Construction on the pilot project begins in June in the sediment plain above the
Sediment Retention Structure, 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,” said Johnson. “People will be able to see the construction from viewing areasnear the SRS and Hoffstadt Bluffs Visitors Center.”

A map showing the restricted area can be found at www.nwp.usace.army.mil/projects/mountsthelens.asp.