Abstract: To achieve a harmony of hydropower development and ecological protection, scientific, quantitative, and efficient analysis of the impact of hydropower station operation on river ecosystem has become a hot research topic in water conservancy. This paper describes a high-efficient and high-accuracy habitat suitability model that couples a habitat suitability model with a hydrodynamic model based on the finite volume method using Godunov scheme, and GPU acceleration technology. Using this coupling model, we simulate the spawning habitats under different river discharges, in a case study of an upper Yellow River section downstream of Yehu Gorge, to determine the ecological flow suitable for spawning of the target fish, Gymnocypris eckloni, after completion of the hydropower station. The results show that under the discharges of 87.5 - 139.0 m3/s and 338.0 - 562.5 m3/s, the effective habitat area suitable for reproduction of this fish covers more than 90.0% of the largest habitat area. To ensure a good condition of the spawning habitat, we suggest an ecological flow be around 499.2 m3/s after completion of this hydropower station. The results are useful for ecological protection of the native fish habitats in the upper Yellow River and also for evaluation of hydropower project impacts on aquatic organisms.

Key words: habitat suitability model, hydrodynamic model, GPU-acceleration, ecological flow