PNNL

Abstract

The biological response of fish to turbine passage has been of concern for several decades and emphasized recently by consideration of hydro as a “green” power source. The current state-of-the-art of hydro-turbine biological performance assessment, while still inadequate, has advanced considerably the past 10 years. For example, the importance of assessment of exposure to pressure changes during turbine passage has been emphasized by findings of laboratory studies of rapid decompression. It is now very clear that hydroturbine biological assessment must consider the physiological state and behavior of fish at turbine entry and changes in physiological state that drive aspects of behavior during tailrace passage. Such considerations are in addition to concerns about exposure of fish to mechanical and pressure sources of injury during turbine passage. Experimental designs and assessment tools have evolved for acclimation of test fish, observation of test fish behavior at approach and upon exit from the turbine environment, and precise estimation of turbine passage mortality. Fish condition assessment continues to improve permitting better classification of observed injuries to injury mechanisms. Computational fluid dynamics (CFD) models and other computer models permit detailed investigation of the turbine passage environment and development of hypotheses that can be tested in field studies using live fish. Risk assessment techniques permit synthesis of laboratory and in-field study findings and estimation of population level effects over a wide range of turbine operation scenarios. Risk assessment is also evolving to provide input to turbine runner design. These developments, and others, have resulted in more productive biological performance assessment studies and will continue to evolve and improve the quantity and quality of information obtained from costly live fish hydroturbine passage studies. This paper reviews the history of hydro-turbine biological assessment, presents the current state-of-the-art, and identify areas needing improvement.