Study on the simulation of reservoir water environment and the optimization of ecological water replenishment effect: taking Luhun Reservoir as an example

With global climate change and extreme weather events, water scarcity and environmental degradation are becoming increasingly prominent. Ecological replenishment is one important measure to enhance water quality in reservoirs. To address the severe pollution and ecological degradation problems of the Luhun Reservoir, this paper uses MIKE21 software to construct a coupled hydrodynamic-water quality model. Design six recharge scenarios to compare and explore the enhancement of reservoir water quality for these scenarios. Evaluate the water quality status of these options using the single-factor index method and the combined pollution index method. The results show that due to the ecological replenishment, the pollutant concentration leads the phenomenon of gradient diffusion to the center of the reservoir, and the average improvement rate of water quality is up to 40.22%. Schemes 2 and 5 have the lowest integrated pollution index. The most significant improvement in water quality was achieved at the same total recharge conditions, using 0.5 times the flow rate and two times the recharge time of the actual recharge project. The study results provide theoretical and technical support for the future management of the reservoir water environment.