Derby Dam fish screen changes Truckee River future

Back in the early 1900s, the first project for the newly formed U.S. Reclamation Service – now the U.S. Bureau of Reclamation – was construction of the Derby Dam on the Truckee River.
As part of the sweeping Newlands Project to provide irrigation for arid land in Churchill, Lyon, Storey and Washoe counties, the diversion dam 20 miles east of Reno was completed in 1905. It sends water into the Truckee Canal, which runs 32 miles and provides water to Fernley and Hazen before emptying into the Carson River. Fallon’s water, drawn from an aquifer beneath the Lahontan Valley, is refreshed from this source as well.
The 31-foot high, 1,300-foot-long Derby Dam has long been a source of water-rights controversy – beloved Carson City and Virginia City newspaperman Mark Twain famously wrote that “Whiskey’s for drinking, water’s for fighting!” In the decades since the Derby Dam was completed, the water level at Pyramid Lake has dropped more than 80 feet, and the native Lahontan cutthroat trout became extinct in both the lake and its migratory spawning grounds upstream on the Truckee River, which once supported a robust commercial fishery.
A fish screen completed last year by Granite Construction allowed the first fish to bypass the Derby Dam in more than a century. Construction of Derby Dam fish screen was named one of the most significant construction projects of 2021 and earned Granite the Associated General Contractors Construction Risk Partners Build America Merit Award for best construction management practices on a civil project.
NNBW in April spoke with the Granite team, along with Carson City-based representatives from the Bureau of Reclamation, about the project.

Introduction of Pilot Peak trout to Pyramid Lake
In the 2000s, Lahontan cutthroat were re-introduced to Pyramid Lake after their miraculous discovery in a small creek near remote Pilot Peak in eastern Elko County. Although the Bureau completed a fish passage in 2004 to allow Lahontan cutthroat trout to once again migrate upstream, Schoenfeld said, there wasn’t a screen to keep them from entering the Truckee Canal, so fish were never allowed passage above Derby Dam.
“Once they get above Derby Dam, we do not want them getting into the Truckee Canal and into Lahontan,” he said. “The water is too warm. The fish screen will screen those fish, so instead of getting entrained in the Truckee Canal, it puts them back into the river below Derby Dam.”
Alexis Vaivoda, executive vice president with the Farmers Conservation Alliance, told NNBW that initial site visits and meetings with the Bureau of Reclamation and U.S. Fish and Wildlife Service led to brainstorming sessions and ultimately the use of the FCA’s innovative Farmer’s Screen, a horizontal fish screen technology that diverts water from rivers without harming fish or getting clogged by debris.
The screen installed on the Truckee River is the largest FCA fish screen ever installed. A few of the many challenges of the project included the varying flow rates of the Truckee River, and ensuring that downstream water-rights holders got their allotments during the 11-month construction process, Vaivoda said.
“We needed to provide the Truckee Carson Water District and all the agricultural water users downstream with the ability to have their water supplied throughout the project,” she said. “We also opened up about 37 miles of additional spawning habitat above Derby Dam.”

Construction of the FCA fish screen
Securing all the necessary permits was akin to running a marathon in just a few hours for the Granite preconstruction team.
“As a team, we sat down and identified all the permits that were required for this project – and every permit under the sun was required,” said Tina Mudd, environmental manager at Granite Construction. “We assigned team members to push those permits through, and we actually permitted this project in about eight months. Generally, when you are working in a river in this scope, it takes about 18 months of permitting.
“We were able to drive the permitting through the CMAR (construction manager at risk) process and through the partnerships that this team had. We all took pieces of the permits and did everything we could to push them through,” Mudd added.
The construction team, meanwhile, was brought on to estimate the project, develop costs, assist with design, value engineering and other key preconstruction services, said Cody Cummings, project manager for Granite Construction.
The team also identified key challenges, such as access. The fish screen was installed on the south side of the river, but site access was on the opposite side of the river, posing a quandary of how to get materials and equipment to the site.
The team looked at using an old bridge upstream at Painted Rock, but it was deemed too far away from the site, and it also had weight restrictions. Ultimately, a temporary bridge was installed, and that solution proved so effective that permits are being secured to keep it in place.
“That was a huge step in being able to meet a tight timeline,” Cummings said. “Scheduling was another significant challenge – 11 months, and there was a lot of structural concrete and excavation, as well as the phasing and sequencing of the work.”
More than 7,000 yards of structural concrete was poured to construct the fish screen, Cummings added. The forebay was constructed first, followed by the aftbay so water could be diverted and create a dry zone to complete the rest of the structure, Cummings said.
Site logistics were especially challenging.
“The site is not that large to stage equipment and cranes,” Cummings said.
A perimeter system of wells with pumps running 24 hour a day also was required during excavation due to the high water table at the site, Cummings added.
“Honestly, though, it went really smoothly, and I think that goes back to the amount of time we spent in preconstruction,” he said. “We spent several months figuring out the best way to build it, the sequence of how we wanted to construct it, and the resources we needed.
Brian Turmail, vice president of public affairs & strategic initiatives for AGC of America, told NNBW that the technical expertise required to pull off the project was one of the main aspects that impressed AGC judges and ultimately led to the merit award.
“The judges were impressed with how the team overcame a number of significant challenges to complete the project and install the largest horizontal fish screen in the U.S,” Turmail said. “The judges were also impressed with the work Granite did to keep the broader project team together and collaborative.”


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