Physical-based model of fish movement in fish extraction facilities

Fish collection or diversion facilities are structures designed to remove fish from a channel where they may be endangered from pumps, power plants, or irrigation systems. The Tracy Fish Collection Facility in the Central Valley of California (USA) collects endangered and economically important species before they can enter the Delta Mendota Canal. We describe the structure, sensitivity, and preliminary validation of a model that moves fish through this louver-type fish collection facility. The model is individual-based and moves fish subject to fundamental physical forces in the flowing medium and simple obstacle avoidance behaviors. Fluid dynamics are obtained by solving the Navier–Stokes equations. The primary model output is the salvage efficiency of the facility design. Monte Carlo simulation showed that the mean salvage efficiency is within the variability of field estimates. The most sensitive variables of the model are the initial cross-channel position of the fish and its initial energy reserves. The implications of our results for future collection facility designs are discussed.