Fish Passage
Agreements & Biological Opinions | Fish Passage | Hatcheries
Habitat Restoration & Conservation
For more than 25 years, Grant PUD has been an innovator in fish protection efforts. The utility has engaged in extensive fisheries research and initiated numerous fish protection programs. These multimillion dollar fish conservation programs, developed in consultation with fishery agencies and tribes, play a critical role in the region’s efforts to preserve the quality of Northwest fish populations.
Advanced Turbine
Grant PUD is in the process of installing advanced turbines at Wanapum Dam. These turbines, the first installed in a hydroelectric powerhouse in the U.S., are the result of several years of research and testing designed to learn how dam operators can achieve higher survival rates for juvenile fish passing through turbines. Tests conducted in 2005 on the new turbine and an adjacent existing model revealed an overall survival estimate of 97.8 percent for smolts passing through the new turbine compared to survival rate of 97.7 percent in the existing turbine.
Off-Ladder Adult Fish Trap
Other fish protection and monitoring efforts include construction of the Off-Ladder Adult Fish Trap facility at Priest Rapids Dam, completed in 2007. This state-of-the-art, 4.2 million facility allows research and management activities, such as the collection of fish stock assessment surveys of returning adult fish and broodstock collection of local hatchery production.
The Off-Ladder Adult Fish Trap facility, operated two days a week from July until mid-October, is a monitoring point for upstream migrating steelhead in the mid-Columbia River system. The device, which replaces a single trap built more than 20 years ago, diverts steelhead from the fish ladder into a holding tank where they are examined, measured, recorded and implanted with a Passive Integrated Transponder-tag before being returned to a channel that routes them back to the fish ladder. While steelhead are diverted into a holding tank, other species, including shad, sockeye, whitefish and Chinook, are re-routed back into the fish ladder to continue their journey upstream.
Priest Rapids Topspill Prototype
The Priest Rapids Topspill Prototype is a device that will aid the passage of downstream migrating salmon and steelhead. The topspill device has been in development since 2005, when testing started to determine the best location on the dam for the device. Testing involved the use of acoustic-tagged yearling Chinook salmon tracked through the forebay of Priest Rapids Dam to determine the route they followed. Tests continue as biologists and engineers work to establish the best and final design for the topspill device.
Spill
Grant PUD spills more water annually to enhance fish passage than any other dam operator in the region. Efforts to achieve 95 percent survival of young salmon and steelhead passing through the Priest Rapids Project have resulted in an average of 50 percent of the river flow during juvenile salmon migration. In recent years, the number of salmon and steelhead returning to spawn has reached record levels, in part due to investments in the hydropower system.
Helicopter Transport
One of Grant PUD’s recent innovative efforts monitors spill effectiveness through the utilization of a helicopter to transport young Chinook salmon above and below the dams. The salmon are tagged with miniature computer chips that emit a radio frequency that allows them to be monitored as they pass through the project.
Predator Control
Grant PUD implements a series of programs aimed at reducing the predators of migrating juvenile salmon. A variety of methods are used to deter the feeding behavior of avian predators, including an array of wires stretched over the Wanapum and Priest Rapids powerhouse tailrace areas. Grant PUD also implements a program to reduce juvenile salmon mortality associated with predation by northern pikeminnow in the Priest Rapids Project.
Adult Fishways
Grant PUD operates and maintains two fishways at each dam designed to allow safe passage upstream for adult fish returning from the ocean to their native waters. During the August to November upstream fish migration period, Grant PUD operates the sluiceways at both Priest Rapids and Wanapum Dams to provide a fallback passage route for steelhead and fall Chinook.
Adult Fish Detection
To further assist regional fish monitoring and evaluation programs, Grant PUD installed adult Passive Integrator Transponder (PIT)-tag detection equipment in both fishways at Priest Rapids Dam in 2003. These PIT-tag readers monitor downstream survival of fish and their return upstream, providing valuable data regarding fish migration histories.
Fish Counting
Grant PUD is committed to providing accurate counts of adult fish migrating through the right and left bank fishways at Priest Rapids and Wanapum dams. A state-of-the-art video system allows 24 hours of fish counting April 15 through November 15. These counts are used to provide information to an interactive data resource designed for research and management purposes relating to the Columbia Basin salmon populations and river environment.
Water Quality
Grant PUD continues to investigate alternatives for reducing total dissolved gas reduction in the Priest Rapids and Wanapum spillways. Total dissolved gas, or TDG, is the result of small air bubbles becoming dissolved in water. Effects of TDG on fish are akin to the bends (or nitrogen narcosis) in humans. At very high levels, TDG results in bubbles which can be lethal to fish. Standards have been established by the Washington Department of Ecology to protect aquatic life, which can be adversely impacted by high levels of TDG.
Wanapum Fish Bypass
As part of the objective to achieve at least 95 percent survival of juvenile salmon (anadromous salmonid smolts) passing Wanapum Dam, Grant PUD built an alternative passage route that allows an opportunity for smolts to bypass the turbines.
The Wanapum Fish Bypass consists of a 290 foot long chute with an opening of 18.5 feet and an exit width of 90 feet. The “chute” carries a bypass flow of 20,000 cubic feet per second (cfs). Vertical and inclined gates make it possible to set lower flow rates.
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