Threatened fish get new home on the lower American River

Written by: Todd Plain

Construction equipment along lower American River increasing the availability of spawning gravel and rearing habitat for threatened salmonidsSacramento, Calif. – The loud beeps and heavy rumbles of construction equipment are echoing again across the lower American River, this time at a big bend 4 miles downstream of Nimbus Dam called Sacramento Bar. Here, gravel, sand and river rocks of various sizes are excavated, sorted and washed. Fallen trees and bushes are being dug up or brought in for insertion into side channels yet to be completed.

It’s all part of a federally-backed program designed to increase the availability of spawning gravel and rearing habitat for threatened salmonids, namely Chinook salmon and steelhead trout.

“Our dams serve many useful purposes but they also block natural sediment supply and natural river flows,” says Bureau of Reclamation fish biologist and project manager, John Hannon. “Without the unimpeded ‘flushing’ type of river flows, habitat complexity declines making it more difficult for fish to spawn and rear. So, we need to re-establish or recreate suitable habitat for migrating fish.”

Reclamation dam operators can manipulate a river’s flushing flows but with constant erosion and ensuing limited habitat, most fish migrating up the American River eventually dead-end at Nimbus Dam or the Nimbus Fish Hatchery.

“Since 2008, we’ve restored seven spawning and rearing habitat sites below Nimbus Dam,” says Hannon who manages similar work in the Sacramento and Stanislaus rivers. “We’ve identified another eight sites and we’re starting with Sacramento Bar, with the goal of addressing the others one site per year.”

Hannon has seen successful adaptation of the new habitat firsthand. “We know the fish are using the sites from spawning surveys conducted from the air and ground, and by swimming with masks and snorkels,” he said. If it sounds like a big job and a lot of work for one person—it is.

“It’s truly a collaborative effort. With a big help from the local American River partnering agencies and support of the community,” said Hannon. “Without them and all of us working together to help save the fish, these projects—this program—doesn’t work.”

The salmonid restoration program is managed by Reclamation, in partnership with U.S. Fish and Wildlife Service, the Sacramento Water Forum, California Department of Fish and Wildlife, and Sacramento County Regional Parks. It’s a result of the Central Valley Project Improvement Act of 1992, multipurpose legislation intended to offset impacts from the construction and operation of Reclamation’s massive California water delivery system—the Central Valley Project.

Published on September 06, 2016

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