Validation of Francis–Kaplan Turbine Blade Strike Models for Adult and Juvenile Atlantic Salmon (Salmo Salar, L.) and Anadromous Brown Trout (Salmo Trutta, L.) Passing High Head Turbines

• Published in: Sustainability
• Main Authors: Vikström, Linda, Leonardsson, Kjell, Leander, Johan, Shry, Samuel, Calles, Olle, Hellström, Gustav
• Format: Article in Journal/Newspaper
• Language: English
• Published: Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013) 2020
• Subjects: modeling; validation; blade strike; kelt; turbine passage; animal movement and migrations; animal conservation; hydropower sustainability; ecohydraulics; Francis turbines; Other Biological Topics; Annan biologi; Atlantic salmon; Salmo salar
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-80923; https://doi.org/10.3390/su12166384

The negative eects of hydroelectric power (HEP) on salmonid populations has longbeen recognized and studied. Downstream passage through turbines may potentially constitute asignificant source of mortality for both juvenile and adult fish in regulated rivers. Numerical modelshave been developed to calculate turbine passage mortality based on the probability of collision withthe turbine blades, but although widely used in management and conservation, their performanceis rarely validated in terms of the accuracy and bias of the mortality estimates. In this study,we evaluated commonly used blade strike models for Kaplan and Francis turbines by comparingmodel predictions with observed passage mortalities for juvenile 13–27 cm and adult 52–94 cmAtlantic salmon (Salmo salar, L.) and anadromous brown trout (Salmo trutta, L.) acquired by acoustictelemetry. Predictions made for juveniles aligned closer with observed mortality for both Kaplan andFrancis turbines (within 1–3% percentage points). However, the model severely underestimated themortality of adult fish passing through Francis turbines, with up to 50% percentage points dierencebetween predicted and observed mortalities. Furthermore, the model did not capture a clear negativecorrelation between mortality and discharge observed for salmon between 50–60 cm (grilse). Weconcluded that blade strike models are a useful tool for quantifying passage mortality for salmonidsmolts passing large, high-head turbines, but that the same models should be used with care whentrying to estimate the passage mortality of kelts in iteroparous populations. We also concluded thatthe major cause of passage mortality for juveniles is injury by collision with the turbine blade, butthat other factors seem to contribute substantially to the passage mortality of kelts. Our study reportslow mortality for smolts up to 27 cm passing through Kaplan and Francis turbines (0–12%), but highmortality for salmon over 50 cm passing though Francis turbines (56–81%).