Author(s): Rui Han; Ruonan Li
Keywords: No Keywords
Abstract: Due to the operations of hydraulic structures, the flow regimes in downstream are dramatically altered, causing lots of changes on the aquatic ecosystem. To evaluate those effects on the fish habitats, an integrated model coupled a two-dimensional water quality module and an individual based fish module was developed. In the individual based fish module, fish swimming behavior to hydrodynamic conditions was taken into consideration. Through field surveys and laboratory flume experiments, the fish preference to flow conditions were investigated and defined. Compared to the previous version of the model, the main improvements consist in the features of population grouping and escaping, space competition, and different adapt abilities to flow changes. The developed model was applied to a compound channel of the Lijiang River in the southwest China, where the flow has been largely modified by the upstream reservoir. The model was validated by the historical fish survey data and the field observations conducted during the study. The scenario analysis showed that, if only the flow aspect was concerned, the flow regulations had positive effects on the non-migrating fish grass carp, but had little impact on crucian carp. In particular, the present operation scheme from early April to end of May should be improved. The methodologies developed in the research can provide support to optimize reservoir operation schemes and improve river management.