Validation of a model to predict fish passage mortality in pumping stations

Abstract

A total of 1253 live cyprinids and eel were exposed to a centrifugal pump to study fish damage rates in a wide operating range. The observed types of injuries were consistent with a mechanical cause of damage. The measured mortality rates for cyprinids show a fair agreement with a blade strike model based on empirical data by Electric Power Research Institute. Analysis of the experiments with eel led to a new correlation for the blade mortality ratio for this species; lethal injury rate is shown to be zero up to a strike velocity of 8 m·s–1 and increases linearly to 42% for a strike velocity of 15 m·s–1. Use was made of video recordings that provided valuable information on the orientation and distribution of fish approaching the impeller. Results are presented using a new method to visualize fish mortality from a pump in its entire operating range using graphs of pressure head versus flow rate. The theory of pump hydrodynamics is used to derive a method to scale results of fish damage rate, obtained either by a model or by experiments, to different pump sizes, shaft speeds, or fish lengths. This will prove essential for a valid interpretation of pump experiments with fish.