Author(s): Zhenhua Cui; Shuai Niu; Ni Xiao; Liang Wang; Wenlin Zhai

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Keywords: Chishui River; Environmental flow; Hydraulic analysis; Weighted usable area (WUA)

Abstract: The National Nature Reserve for the Rare and Endemic fishes of the Upper Reaches of the Yangtze River is located in the Chishui River Basin, and some small hydropower stations have been decommissioned in recent years. Determining the sensitive environmental flow to restore the suitability of fish habitats has become increasingly urgent and necessary. This paper employs a habitat simulation method based on the principles of IFIM. Sinogastromyzon sichangensis and Acrossocheilus monticolus (Günther) are selected as target species for habitat simulation in the watershed. By analyzing the Weighted Usable Area (WUA), changes in suitable physical habitats under various environmental flow during sensitive periods are examined, thus determining the optimal range of environmental flow for the target fish species. Through calculations with 28 flow simulation schemes, it is revealed that the optimal flow range is between 2 to 20 m3/s, and the area of river habitat suitable for fish survival accounts for over 20% of the total river reach area. The findings of this project provide technical support for calculating the environmental flow for reservoirs during sensitive periods of rare fishes and for optimal reservoir regulation.

DOI: https://doi.org/10.64697/HIC2024_P577

Year: 2024