Biologists work to save fish after landslide

NILE, Wash. – A gigantic landslide that buried a highway, uprooted homes and rerouted a river in Washington state’s Cascade Range left hundreds of smaller victims: fish.

The landslide that inundated the Naches River last month created a barrier of millions of cubic yards of silt, mud and rock that slowed – and likely confused – spawning salmon and hungry trout. Then workers opened a freshly dug river channel that stranded small fish in ponds and marshes.

Fisheries biologists from 10 government agencies and private groups are working shifts to try to save the fish. The effort marks a step forward in rebuilding a rural area where the focus has been aiding the residents of as many as 600 homes who could be cut off from the outside world because of flooding or snowy weather this winter.

“The fish need help too,” said Derek Newton, 70, who has volunteered for the Nile Fire Department for 10 years. “It’s important to see them come back.”

A quarter-mile stretch of hillside collapsed in the Oct. 11 slide in the Nile Valley, an area of scattered homes and cabins next to the tree-lined river with steep, rocky hills on each side. Leaning and downed trees, a mountain of dirt and rock and snapped pieces of highway remain more than a month later in the area – part of a much larger prehistoric landslide thousands of years ago.

“It’s probably one of the biggest events we’ll see in our lifetime, but looking at the landscape scale out here, it’s a pretty small thing,” said Craig Broadhead, of the Transportation Department’s environmental office.

Geologists for the state Transportation Department are still working to determine the exact cause of the slide and the area’s stability. Gravel has been laid for a temporary replacement to the highway, to be paved next week. Construction on a new permanent road is at least a couple of years away.

The state expects to have spent nearly $8 million for emergency road work in the days immediately after the slide. Yakima County, which spent about $1.8 million to demolish some homes or buy property for the new road or river channel, expects its total tally to be about $3 million.

For fish, the recent landslide likely wasn’t a catastrophic event, even though it lifted the river elevation some 50 feet, said Broadhead. Most adult fish were able to swim out as the water receded.

But rerouting the river channel stranded hundreds – perhaps thousands – of migratory and resident fish among the shrubs and cottonwood trees now in several feet of water.

Of particular concern are resident bull trout and steelhead, a form of the rainbow trout that migrates to the ocean. Both are threatened species.