Fish Return Design Guidelines

One approach for reducing impingement mortality at cooling water intake structures (CWIS) that is expected to be included in the final 316(b) regulations is the installation of modified traveling water screens (TWS).  A critical component of an effective modified TWS installation is a system for safely returning collected organisms back to the source water body.  Fish return guidelines, specifically for the TWS fish return systems, were developed in 1982 (ASCE 1982).  Since then, several guidelines for fish returns and other fish handling systems (e.g., fish bypasses, spillways, intakes, and fish screens) have become available.  Additional research into individual stressors, (turbulence, shear, impact, etc.) as well as laboratory and field evaluations of fish returns have also been conducted.  Based on the existing guidelines and recent fish return evaluations, the Electric Power Research Institute (EPRI) has synthesized new guidelines to aid in the design of an effective fish return.  This presentation summarizes EPRI's proposed fish return guidelines.