Flooding May Have Hurt Chinook Run Fisheries Expert Afraid Spawning Nests Flushed

An Idaho Department of Fish and Game anadromous fisheries expert fears flooding on the Clearwater River might have further damaged an already threatened fall chinook salmon run.

Unusually high water in the river from runoff and rain may have flushed many of the salmon spawning nests - or redds - downstream.

“This flood couldn’t have come at a worse time,” Steve Pettit, a Fish and Game fisheries biologist in Lewiston, said Friday. “The redds that had already been built in the Clearwater prior to this flood stand a good chance of being destroyed because of flood water.”

At Cherry Lane, on the Clearwater near Lewiston, Pettit said nearly 20 redds may have been wiped out when flows reached their highest levels in two or three decades for the late fall season.

“This could be devastating, at least for the Clearwater group,” he said. “By far the most incredible flooding took place in the Clearwater basin.”

Across the basin, high temperatures and near-record rainfall combined to trigger mud and rock slides, which in turn overwhelmed a number of creeks and rivers during the past week. The slides and flooding have forced road closures, campgrounds have been inundated and creek banks have failed.

“It could have a severe impact on fish,” Pettit said. “Anadromous presmolts have been literally flushed out of the streams that they were going to winter in. Now they are in the main stem” of the Clearwater River, and “it’s anybody’s guess if they will be able to migrate back next year.”