Logjams on the Mashel River help fish, protect property

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A construction crew on the Mashel River starts on a logjam.

EATONVILLE –New logjams in the Mashel River – being built this summer by the Nisqually Indian Tribe – will provide habitat for fish and help protect property from damaging floods. The series of logjams will help protect riverside property which sustained damage during last winter’s 100-year flood, while also providing vital habitat to salmon.

“Right now, both people and salmon are in danger because water just flows too quickly through this stretch,” said David Troutt, natural resources director for the tribe. The property’s owner lost an outbuilding and several hundred feet of bank to the flood.

“Bank hardening and logging that have decreased the ground’s ability to soak up water has made the damaging impacts of floods worse,” Troutt said. The logjams will both protect the banks while also slowing the flow of floodwaters.

The tribe’s project will tie into a planned logjam effort by the state Department of Transportation (DOT) to protect a highway bridge. The DOT project to install logjams is planned for 2010.

Logjams are important features in the lifecycle of salmon because they create good habitat for juvenile salmon. Because of the loss of large streamside trees, logjams are largely missing from rivers like the Mashel. “Over the years logging took away most of the material that eventually would have formed logjams,” Troutt said. “Juvenile salmon use logjams as places to hide from predators and find food.”

This year’s logjam project will also tie into an extensive logjam project that was built in the last few years just upstream. “We’ve seen direct evidence that the logjams we’ve built in the last few years not only blunt the impacts of floods, but also boost juvenile salmon populations,” Troutt said.

A large rock berm that had protected the city of Eatonville’s Smallwood Park was replaced by a series of large logjams. “Two significant floods have battered those structures, but they’ve survived,” Troutt said.

At the same time, surveys have found a booming juvenile coho population around the jams. “Our biologists found more than 2,500 coho living in the same part of the Mashel, up from around 900 before the logjams,” Troutt said. “These fish are finding the river a much better place to be now.” In addition to coho salmon, the logjams are also expected to benefit chinook and steelhead, both of which are listed as “threatened” under the federal Endangered Species Act.

“Lack of high quality habitat is the major factor in declining salmon populations on the Nisqually River,” Troutt said. “This project shows that you can restore and protect habitat while protecting people as well.”


For more information, contact: David Troutt, natural resources director, Nisqually Indian Tribe, (360) 438-8687. Emmett O’Connell, information officer, NWIFC, (360) 528-4304, [email protected].