Pleasing results have been unveiled from an elaborate, expensive experiment to measure whether passage improvements are helping to lift salmon survival at Columbia-Snake river dams above targets set out in the federal fish protection plan.
Over the spring and summer nearly 50,000 young fish were captured, implanted with Juvenile Salmon Acoustic Telemetry System micro-acoustic transmitters and passive integrated transponder tags so they could be detected just above and below six dams (four on the Columbia and two on the lower Snake river).
All 14 tests conducted in 2012 for dam passage survival exceeded performance standards established in NOAA Fisheries 2008 biological opinion for the Federal Columbia River Power System. The BiOp lines out actions and research needs aimed at improving survival of salmon and steelhead stock that are listed under Endangered Species Act.
The BiOp judges whether the federal Columbia-Snake hydro system jeopardizes the survival of 13 basin salmon and steelhead stocks that are ESA listed. Its prescriptions are designed to mitigate for impacts and avoid jeopardizing the survival of fish stocks.
The research, which began with testing at lower Columbia dams in 2010, is believed to be the most extensive of its kind.
“No one else in the world is doing a telemetry study like this,” Mike Langeslay of the U.S. Army Corps of Engineers, told researchers gathered in early December for the Technical Management Team’s annual “year-end review” of hydro operations implemented to improve fish migration conditions.
Tags alone for the 2012 tests cost $10 million, said Langeslay.
An even more detailed look at study methods and results was provided by a team of researchers during the Corps’ annual Anadromous Fish Evaluation Program research review at the end of November.
The tests involved the release of groups of three fish species during the spring (yearling chinook and steelhead) and summer (subyearling chinook). They included tests of each of the three species at the lower Snake’s Little Goose and Lower Monumental dams and at Columbia’s John Day and McNary dams. Only subyearling fall chinook were used in tests at the Columbia’s Bonneville and The Dalles dams.
The BiOp standards are for survival of 96 percent or better at each dam for the spring migrants, and 93 percent or better percent for summer migrants.
“It was a very robust result,” said University of Washington professor and researcher John Skalski.
NOAA Fisheries Northwest Region FCRPS Branch chief Ritchie Graves also liked the results.
“By and large the configurations and operations are having the intended results,” Graves said of structural and operational improvements made to improve fish survival up and down the hydro system. They include fine-tuning spill, the installation of surface bypass devices such as spillway weirs that move salmon and steelhead quickly and safely past dam and The Dalles Dam’s new spillwall.
An example is completion of the spillwall in 2011 which helps steer young fish downriver quickly and away from areas where large numbers of predators lurk. Survival was estimated to be only 91 percent in the spring of 2004 and 93 percent in the spring of 2005.
For the past two years The Dalles survival has been at or above the performance standards for both spring and summer migrants.
Graves pointed out, however, that dam survival “is just one of the metrics” that’s called for in the BiOp to track performance of fish, and to measure the performance of mitigation actions taken to boost populations. Reach survival, i.e. down through dams and their reservoirs, and adult performance are among the other factors weighed.
Survival through Bonneville Dam this summer for subyearling fall chinook averaged more than 97 percent in 2012, well above the 93 percent performance standard.
The tests involve charting fish progress through all available passage routes at the dams, including turbines, mechanical passage devices, spillways and surface passage routes such weirs and, in Bonneville’s case, the “corner collector.” In an initial year of testing subyearling passage at Bonneville in 2010 survival was just shy of 96 percent.
The Dalles Dam data showed subyearling survival this year of nearly 95 percent as compared to 94 percent in 2010. Yearling chinook passage survival at the dam was right at the performance standard in 2010 and 2011, while steelhead survival jumped from just over 95 percent in 2010 to 99.5 percent in 2011.
Yearling chinook dam passage at John Day Dam this year was estimated to be just under 97 percent, which was roughly the same as in 2011. For steelhead the estimate was 97.44 percent, up from 95.67 in 2011.
In a first year of testing of subyearling chinook at John Day the passage estimate was 94.14 percent in 2012.
Performance testing took place for the first year at McNary Dam in 2012. Researchers estimate dam passage survival was 96 percent for yearling chinook, 99 percent for steelhead and 97.47 percent for subyearlings.
At the lower Snake’s Lower Monumental Dam, 2012 dam passage survival estimates were 98.7 percent for yearlings, 98.3 percent for steelhead and 97.9 percent for subyearling chinook. At little Goose Dam the estimates were 98.2 percent for yearling spring chinook, 99.5 percent for steelhead and 95.4 percent for subyearlings.
For the Snake River tests 6,000 yearling chinook and 6,000 steelhead were captured above Lower Monumental during the spring season, implanted with tags and released at five different locations between river kilometer 133 and rkm 40, according to Geoffrey McMichael of Pacific Northwest National Laboratory. He gave a presentation at the AFEP gathering on lower Snake performance standard testing designs and methods.
A total of 11,000 subyearling Snake River fall chinook were released in small batches over the course of the summer season.
“To detect tagged fish, cabled receiver systems were deployed on the upstream dam face to provide high detection probabilities and detailed information of routes of passage at the dams,” the study abstract says.
“In addition, autonomous receivers were deployed in arrays in dam forebay and tailraces to provide further detection data to support the survival estimation and for determination of metrics specified in the Fish Accords.”
The accords are agreements on fish and wildlife mitigation funding among the federal agencies involved in dam operations and states and tribes. The so-called federal “action” agencies are the Corps and the Bureau of Reclamation, which operate federal hydro projects, and the Bonneville Power Administration, which markets power generated and funds a large share of the mitigation work.
Testing at the two Snake River dams employed cabled receivers, including 71 hydrophones, 4.8 miles of cable, 19 quad-channel amps and servers, as well as 30 autonomous receivers in eight arrays that required eight servicing trips and 311 individual deployments.
Similar cable arrays were deployed for the spring and summer tests at the four lower Columbia dams, as well as autonodes at 14 in-river sites. A total of 6,000 yearlings, 6,000 steelhead and about 14,000 subyearlings were used in those tests. Collection of the fish occurred at John Day Dam smolt monitoring facility.