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Log piles in river have a purpose

4:17 pm July 25th, 2012

Another summer of work to make the Mashel River more salmon-friendly and flood-resistant is underway.

The state Department of Transportation (DOT) last week began work on installing log structures in the river. The structures, which resemble natural-occurring log jams, will hug the river bank in six locations downstream from the State Route 161 bridge in Eatonville, offering “scour protection” for the highway and bridge and habitat for salmon.

The state-funded project is the latest effort to help curb riverbank erosion and other wear and tear from when the river runs high and fast, including the effects of flooding in 2009, said Jon Deffenbacher, project engineer for DOT.

The current work started with a temporary diversion of the stream. The total project is scheduled to be over in September, which is the end of the seasonal “fish window” when work in and around the river has the least impact on salmon. The final stage – planting trees and shrubs along the river’s edge – will be finished by December if everything goes according to plan.

About 20 workers are involved in the project, which includes drilling holes for pilings that will be part of the log structures and monitoring the river’s water quality to control silt deposits, Deffenbacher said.

As work got underway last week, traffic across the bridge was limited to one lane, with flaggers guiding motorists through the area.

DOT and the Nisqually Tribe have worked closely on the current project and the installation upstream last year of more of the engineered logjams, which have become recognized as a preferred method for improving fish habitat and controlling shoreline erosion in rivers. The tribe has a major role in the fisheries and environmental stewardship of salmon-bearing rivers such as the Mashel.

A worker stands in front of one of the log structures installed in the past year in the Mashel River to provide habitat for salmon and ward off riverbank erosion. More of the engineered structures are being built downstream this summer. (Courtesy photo)

One log structure that was installed last year near the bridge required 15 pilings to anchor the log pile and cost the state more than $1 million and is believed to be the third or fourth done specifically for state-maintained bridges. The first such project was for a State Route 101 bridge over the Hoh River on the Olympic Peninsula.
In addition to the Mashel River, the Nisqually Tribe has restored hundreds of acres of the Nisqually estuary and taken a leadership role in planning salmon recovery throughout the watershed. In addition to managing the placing of log jams, the tribe has donated large trees from reservation land for the projects. Tribal officials have said that restoring and protecting salmon habitat is a major part of the tribe’s overall goal of preserving salmon populations for fishing.

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