Truckee River fish passage to help Lahontan cutthroat

The Lahontan National Fish Hatchery Complex is working alongside the Truckee Meadows Water Authority to rebuild or restructure four dams on the Truckee River as part of the Truckee River Fish Passage Improvement Project.  Tim Loux (left), Lahontan National Fish Hatchery Complex’s regional fish passage program coordinator, and Pat Nielsen, Truckee Meadows Water Authority’s director of distribution maintenance and generation, discuss dam remediation project details at Verdi Power Dam on the Truckee River. Credit: Dan Hottle/USFWS

By Dan Hottle
June 2, 2017

If Lahontan cutthroat trout are to one day migrate barrier-free along the full length of its historic 120-mile range between Nevada’s Pyramid Lake and Lake Tahoe, California, fish passage must first be improved. Four 100-year-old dams on the Truckee River stand in the way.

The Lahontan National Fish Hatchery Complex is working alongside the Truckee Meadows Water Authority to remediate structures managed or co-managed by the water company as part of the Truckee River Fish Passage Improvement Project, with the first phase of construction slated to begin in the fall of 2018.

Staff from the Lahontan National Fish Hatchery Complex work to gather data from Lahontan cutthroat trout spawning in the lower Truckee River near Pyramid Lake. Credit: USFWS

Funding is being provided by the Service’s National Fish Passage Program through its National Aquatic Connectivity Initiative, a grant program that supports fish passage improvement projects that have a national impact.

“The Truckee Meadows Water Authority is proud to help the Service make the Truckee River more conducive for the Lahontan cutthroat trout to be able to spawn the full length of the river,” said Pat Nielson, the water agency’s director of distribution, maintenance and generation.

The Steamboat Ditch Diversion, just west of Verdi, Nevada, will be the first of the four diversions to be remediated with a “nature-like fishway,” a passage structure that will be built over the existing dam.

This design uses roller compacted concrete and natural rock boulders that are deposited into the river in a tiered-level rise from the bottom of the riverbed up and over the top of the dam. It allows the main river channel to remain the passageway so that fish can swim right over the diversion, rather than a traditional fish ladder system that is built next to or around a dam that fish need to be channeled into in order to pass upstream.

“The natural rock weir design is safer and less taxing on the spawning fish because they aren’t using all their body’s energy continuously bumping headfirst into a barrier trying to looking for an opening like they do with many fish ladder designs,” said Tim Loux, the Service's regional fish passage program coordinator. “It also takes up less real estate than it would to add a secondary passage around a dam.”

“Not only will the new passage be more accommodating to fish, it will also benefit recreational river users,” said Nielson. “Currently, kayakers on the river must portage around the existing diversions to be safe. The improved structure will eventually allow them to navigate right through the diversion just as the fish do.”

The partners hope to use Steamboat as a test project before further construction begins on the remaining dams. Slated next are the Verdi Power Dam in the fall of 2019, the Washoe Highlands Dam in 2021 and the Fleisch Diversion Dam in 2022.

Since 2007, the Lahontan National Fish Hatchery complex and National Fish Passage Program have reconnected 78 miles of fish passage and removed or remediated 14 fish passage barriers in the state of Nevada.

 

For more information about Lahontan cutthroat trout and the Lahontan National Fish Hatchery, visit www.fws.gov/lahontannfhc.

For more information on the National Fish Passage Program, visit www.fws.gov/fisheries/whatwedo/nfpp/nfpp.html