Study on the Downstream Fish Responses to Reservoir Operations through an Individual-Based Model

摘要

Due to reservoir operations,mainly for flood control and hydropower generation,the flow regime in the downstream is dramatically altered,which imposes significant impacts on the aquatic ecosystem.To investigate the effects on the fish population dynamics,this study developed a model that integrated a two-dimensional water quality module with an individual-based fish module.The developed model was applied to a compound channel of the Lijiang River where the aquatic ecosystem has been largely affected by the Qingshitan reservoir in the upstream.The water quality module simulated the external forcing for the fish module and the fish module tracked the daily growth and movement of each individual fish.Two different species that are grass carp (Ctenopharyngodon idellus) and crucian carp (Carassius auratus) were modeled.The growth of fish lengths and weight were modeled by an empirical formula.The movement was determined by their preference to the water depth and flow velocity around.The model was verified by the historical fish survey data and the field observations conducted during the study.The research results can provide supports to optimize the reservoir operation schemes so that reduce their environmental impacts.