Trees floating behind dam contribute to salmon recovery

ALDER – Over 100 trees that have fallen into the reservoir behind Alder Dam will be put to use constructing engineered logjams to create salmon habitat on Ohop Creek.

“Trees that wash into the lake from the river and get stuck behind the dam need to be removed before they become a nuisance,” said David Troutt, natural resources manager for the Nisqually Tribe, which is spearheading the effort to gather the logs. “We’re just taking them out and putting them to good use.” Juvenile salmon find both food and shelter within logjams. The structures also slow the flow of the creek, easing adult salmon migration.

“We know logjams benefit salmon because we’ve been monitoring other restoration projects. We really see a difference in the section of river with logjams and those without,” Troutt said. “There are a lot more salmon around the logjams.”

The lake and dam are owned by Tacoma Power, which is turning the trees over for the restoration project for free. The tribe only has to pay for transporting them to a storage site.

To restore Ohop Creek, the tribe and the South Puget Sound Salmon Enhancement Group will dig a new mile-long creek channel and build logjams “Ohop right now is basically a long straight ditch, not a very good place for salmon,” said Kim Gridley, project manager for the enhancement group. “The project will create a richer more varied habitat for salmon.”

Restoring creeks like Ohop is important because it is one of only two tributaries to the Nisqually River that produce chinook. “If some catastrophic event – for example a devastating flood – were to wipe out the entire population of chinook along the mainstem, salmon from Ohop Creek would be able to repopulate the rest of the river,” Troutt said. “By having separate populations in different rivers and creeks in the same watershed, you strengthen the entire population.”

In addition to Puget Sound chinook and steelhead, both of which are listed as “threatened” under the federal Endangered Species Act, Ohop also produces coho and pink salmon and cutthroat trout.

“Suitable trees like these are pretty hard to find and can be pretty expensive,” Troutt said. “The budget for any particular salmon habitat restoration project is pretty tight, so anywhere we can save money on a major cost is great.”


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