变流场情景下基于鱼类游泳特性的上溯通道分析

水电开发对洄游性鱼类的生境造成了影响，预测目标鱼类洄游期的上溯通道可为修建过鱼设施提供依据，从而减缓其负面效应。本文选取虎渡溪航电工程的下游河段作为研究区域，将长薄鳅、白甲鱼、异鳔鳅鮀作为目标鱼类，针对几种目标鱼类的游泳能力对不同流速进行分区后，得出了适用于多种过鱼目标的流速适宜度曲线，然后对研究区域过鱼期的典型流量进行了数值模拟。根据流速适宜度曲线对研究区域的多种过鱼目标进行了流速适宜度评价，并由评价结果预测了满足多目标过鱼要求的上溯通道。结果表明：流速适宜度评价最优区域出现的位置随流量变化而有所不同，低流量运行条件下出现在主流区域，而高流量运行条件下出现在主流区域两侧；上溯的通道面积占总面积的比例也随流量变化而有所不同，低流量运行条件下的占比约为高流量运行条件下的3 ~ 4倍。根据预测通道特征，对鱼道的进口布置及电站运行调度提供了建议。该结果可为相关鱼类的保护工作提供依据。

Analysis of upstream migrating channels based on characteristics of fish swimming in variable flow field

Hydropower development impacts the habitat of migratory fishes significantly. Predicting the upstream migrating passage of target fish in their migration period can provide a basis for construction of fishway facilities so as to mitigate the negative effects. This study selects a research area in the reach downstream from the Huduxi hydropower-navigation project, takes Leptobotia elongate, Onychostoma sima and Gobiobotia bouleugeri as the target fish, and divides the study area into flow zones of different velocities by the swimming performance of these fishes. We obtain flow velocity suitability curves suitable for different fish-passing targets, and numerically simulate typical flow rates in the study area in the fish-passing period. Then, based on the suitability curves, we can evaluate the flow velocity suitability of different fish-passing targets for the study area, and use the evaluations to predict an upstream migrating channel that satisfies the multi-target fish-passing conditions. The results show that the location of fish passage optimized through flow velocity suitability evaluation varies with the channel flow rate. It goes through the mainstream zone under low-flow conditions, while through both sides of the mainstream zone under high-flows. And the proportion of the passage area to the total area also varies with the flow rate, with its low-flow values about 3 to 4 times its high-flow values. By the fish migrating channel predicted in this study, we make suggestions to optimize the layout of fishway inlet and the operation and dispatching of the power station, providing a basis for protecting the related fishes.