Shaken, not stirred: The recipe for a fish-friendly turbine

摘要

It is generally agreed that injuries and mortalities among turbine-passed fish can result from several mechanisms, including rapid and extreme water pressure changes, cavitation, shear, turbulence, and mechanical injuries (strike and grinding). Advances in the instrumentation available for monitoring hydraulic conditions and Computational Fluid Dynamics (CFD) techniques now make it possible both to estimate accurately the levels of these potential injury mechanisms in operating turbines and to predict the levels in new turbine designs. This knowledge can be used to (open quotes)design-out(close quotes) the most significant injury mechanisms in the next generation of turbines. However, further improvements in turbine design are limited by a poor understanding of the levels of mechanical and hydraulic stresses that can be tolerated by turbine-passed fish. The turbine designers need numbers (biological criteria) that define a safety zone for fish within which pressures, shear forces, cavitation, and chance of mechanical strike are all at acceptable levels for survival. This paper presents the results of a literature review of fish responses to the types of biological stresses associated with turbine passage, as studied separately under controlled conditions in the laboratory rather than in combination at field sites. Some of the controlled laboratory and field studies reviewed here were bioassays carried out for reasons unrelated to hydropower production. Analysis of this literature was used to develop provisional biological criteria for hydroelectric turbine designers. These biological criteria have been utilized in the U.S. Department of Energy's Advanced Hydropower Turbine System (AHTS) Program to evaluate the results of conceptual engineering designs and the potential value of future turbine models and prototypes.