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Measures Underway As Part Of Long-Term Strategy To Increase Salmon Survival Above Willamette Dams
Posted on Friday, November 19, 2010 (PST)

A new adult fish collection facility was in operation this summer at Cougar Dam on the South Fork McKenzie River and construction is set to begin this winter to create a new and improved Minto Fish Facility on the North Santiam River as the strategy for improving the lot of threatened upper Willamette River chinook salmon and steelhead starts to unfold.


“There were over 200 wild fish (chinook) that returned to that trap this year,” Mindy Simmons, Willamette Program manager for the U. S. Army Corps of Engineers, said of the Cougar’s facility’s summer of operations. “That’s more than we expected.”


The wild fish, listed under the Endangered Species Act, as are Upper Columbia steelhead, are likely the product of spawning below the dam or from fish trapped previously and transported above the dam to spawn. The Cougar facility is the first of five planned projects aimed at improving the capability of fish managers to safely collect transport adult salmon, steelhead and bull trout to habitat that has long been blocked by dams that make up the Corps’ Willamette Project.


The Cougar facility was built at a cost of $9.7 million. The Corps planned to advertise this week for bids on the Minto project with construction scheduled to begin in January. The trap and haul facility will be built during two midwinter work periods.


“We’re well on our way to implementing” projects outlined in the NOAA Fisheries’ July 2008 Willamette Project biological opinion, Simmons said. The ESA document judged that the planned projects jeopardized the survival of the two listed stocks and described mitigation measures that needed to be implemented to avoid jeopardy.


The Corps expects that most of the capital construction projects called for in the BiOp will be funded through the Columbia River Fish Mitigation program, which has until the past two focused exclusively on improving fish survival up through mainstem Columbia and Snake river hydro projects. The program has been funded through annual congressional appropriations with its costs reimbursed to the U.S. Treasury by BPA.


The BiOp concludes that the Willamette Project adversely affects Upper Willamette River chinook salmon and Upper Willamette River steelhead by blocking access to a large amount of their historical habitat upstream of the dams and by contributing to degradation of their remaining downstream habitat. It covers the Corps’ operation of the 13 project dams and reservoirs, maintenance of 42 miles of revetments, and operation of five mitigation hatcheries in western Oregon’s Willamette River basin. Revetments are fortified riverbanks intended to keep the river from meandering.


The Bonneville Power Administration markets the hydropower generated at the dams, and the U.S. Bureau of Reclamation sells a portion of the water stored in project reservoirs for irrigation.


The NOAA BiOp was developed in consultation with the Corps, BPA and Bureau. The proposed measures to address the effects of dam operations on fish include providing passage at three dams and temperature control at another, adjustments to downstream flows, improving water quality, improving hatchery practices, screening irrigation diversions and conducting habitat mitigation.


In some basins 90 percent of the spawning habitat is upstream of, largely, impassable dams. Salmon and steelhead are native to the North and South Santiam rivers, which drain into the Willamette near Albany. The Willamette enters the Columbia at Portland. The McKenzie and Middle Fork rivers, which empty into the Willamette at Springfield-Eugene, hold salmon and bull trout.


The effects on remaining spawning and rearing habitat located downstream of dams include flow availability and physical habitat, hatchery fish interacting with wild fish and water quality (temperature, dissolved gas).


Some of the flow modifications have already begun. Other measures will be implemented in the short-term to decrease the species’ risk of extinction until the longer-term passage and temperature control measures are completed.


The trap and haul approach was chosen because the project’s dams are all tall, high-head facilities and the operations involve large fluctuations in reservoir levels. Both make the installation of fish ladders impractical.


“We really don’t have much choice,” Simmons told the Northwest Power and Conservation Council’s Fish and Wildlife Committee during an update on Willamette BiOp implementation progress.


The BiOp calls for the completion of improved or new adult fish traps at Minto in 2012, at Foster Dam on the South Santiam in 2013, at Dexter Dam on the Middle Fork Willamette in 2014 and at Fall Creek in 2015. The collection facilities will be used to capture fish for hatchery broodstock and for transport above the dams, where they will be released to spawn on their own.


The existing facilities at Minto were built in 1951 exclusively for the collection of broodstock to fuel mitigation production at Marion Forks Hatchery above Detroit Dam. The current facilities have deteriorated greatly over the years to the point that they are unsafe both for the fish and for the workers that man the trap, Simmons said. They are also inefficient and inadequate to handle the planned future tasks – collecting and holding fish, sorting wild and hatchery fish and species of fish. The new facility will also serve as a juvenile acclimation site for mitigation hatchery production.


“It’s a complicated overhaul,” Simmons said of the Minto project. The collection facilities are also designed to reduce the stress on fish imposed by the human handling.


“We want to reduce what we call prespawning mortality of the adults we release upstream,” Simmons said. Research conducted from 2004-2007 by the University of Idaho found that prespawn mortality rates of greater than 50 percent have been routinely reported in several Willamette tributaries, including the North Santiam, McKenzie and Middle Fork Willamette rivers for transported chinook salmon.


“We’re also trying to make improvements to how they are released” after being transported upriver, Simmons said.


“Total prespawn mortality in the telemetry study was 48 percent, but variability was high with estimates that ranged from 0 to 93 percent for eight individual release groups released across years,” the study abstract says.


In the works is research to evaluate possible methods for capturing the young fish produced by the transported salmon and steelhead. The idea is to capture the juvenile outmigrants and give them a lift around the dams so they can continue their journey to the ocean. The BiOp schedule calls for installation of downstream fish passage facilities at Cougar by 2014, Lookout Point on the Middle Fork by at Detroit by 2021 (or if possible by 2018).


“Downstream passage is the challenge,” Simmons told the Council. The reservoirs are up to nine miles long and there is little information available about how the young fish travel through the reservoirs, how they behave. Collection alternatives could include “head of the reservoir” to catch juveniles as they emerge from the free flowing rivers or floating structures nearer the dams.


The BiOp implementation is very much a learn-as-you-go process.


“We’re working with the region, looking at new information as it comes in,” Simmons said. The strategy includes coordination and data collection functions that include the WATER (Willamette Action Team for Ecosystem Restoration ) committee process and Willamette System Review Study. The WATER committee process includes federal and state agencies, tribes, and local interests in collaborative review and recommendations to Corps. The Willamette review study would help provide information regarding the feasibility and relative benefits of various mitigation measures.

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