Statistical and Biological Study Design Options to Evaluate New Turbine Runners Designed for Safer Fish Passage at Ice Harbor Dam on the Lower Snake River, Washington

Publication Date



Report of the USACE Walla Walla District


study design, acoustic telemetry, balloon tags, salmon, Snake River, turbine passage, sensor fish


New turbine runners designed for safer fish passage will be installed in Units 1, 2 and 3 at Ice Harbor Lock and Dam. Installation of the new runners will begin in 2015 with completion anticipated in 2018. Unit 2 will receive a fixed blade runner and will be the first installed. Unit 1 and Unit 3 will receive identical adjustable blade (Kaplan) runners. Installation of Unit 2 will be complete in early 2016; Units 3 and 1 will be complete in 2017 and 2018 respectively. These new turbine runners are designed to reduce risk of injury to juvenile fish caused by mechanisms such as blade strike and shear, as well as pressure injuries known as barotrauma. Extensive computational fluid dynamics (CFD) and physical hydraulic modeling efforts have focused on achieving good hydraulic conditions with minimum pressures of 83kPa to 103kPa. Maintaining nadir pressures ≥ 83kPa will greatly reduce risk of pressure related injury and mortality experienced by turbine passed juvenile salmonids.

Once installed the new turbine runners require a biological evaluation to establish the biological performance and to validate the design process and criteria. The biological study design should produce precise, accurate survival estimates with the least associated bias possible. A combination of balloon tag and acoustic telemetry study methods will provide turbine survival estimates encompassing both direct and indirect effects of turbine passage. These study methods have been Regionally accepted and used to establish the most recent estimates of turbine passage survival at the lower Snake and Columbia River dams.

Turbine pressure and acceleration data will be collected. These data will be used correlate conditions fish experience as they pass through the turbines with injury and mortality. These data provide evidence of blade strike, shear, and pressure and will also be used to determine how well the new turbine designs meet the biological criteria, and for comparison with and validation of CFD model results.

Pertinent factors are discussed for consideration in choosing and implementing each study design. Statistical analysis methods and preliminary sample sizes associated with these study designs are presented, as well as design assumptions and biases, project operations, and sample season considerations. Internal and external acoustic and balloon tagging methods, release locations for upstream releases and direct turbine intake releases, and acoustic detection array locations are discussed as well.

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