Hydropower Plant Operation Scenarios to Improve Brown Trout Habitat

Abstract

In this study, different hydropower plant operation scenarios were proposed to assess the best habitat alternative for juvenile and adult brown trout (Salmo trutta). Habitat preferences were determined based on field data collection and translated into fuzzy sets and rules for both life-stages. The River2D model was applied to a 100-m long stream segment immediately downstream of the tailrace of the Ermida small hydropower plant (SHP) to obtain a 2D hydrodynamic description for different operation scenarios. Habitat modelling was performed using Casimir Fish 2D by combining flow and fuzzy rules. Overall, simulation results for the juveniles indicated its best habitat conditions for discharges between 0.5 and 1.0 m3s−1 and the adults for 5.0 m3s−1. Five main operation scenarios were developed according to the electricity pricing periods for dry, average and wet year. The decrease in energy revenue was calculated for each operation alternative. The results indicate that it was possible to reduce hydropeaking effects in brown trout habitat through changes in the hydropower plant operation especially for dry years. The methodology developed in this research should be seen as a decision-making tool to help water managers adapt hydropeaking regimes to reduce the ecological impact downstream of hydropower dams. Copyright © 2016 John Wiley & Sons, Ltd.