金沙江下游支流黑水河松新电站幼鱼下行过坝研究

梯级小水电的开发一定程度上破坏了河流连通性并阻碍了鱼类洄游通道。黑水河流域松新坝址为了满足鱼类上行产卵修建了松新鱼道,然而作为洄游物种生命周期中的关键行为,鱼类下行洄游的需求也同等重要。为了寻求一种可行、高效、低损伤的下行过鱼方式,了解河流中不同环境因素对鱼类下行效率的影响,本研究在金沙江下游支流黑水河松新水电站补水通道开展鱼类下行过坝效果评估研究。针对两种鲤科鱼类(棒花鱼Abbottina rivularis和短须裂腹鱼Schizothorax wangchiachii)幼鱼和两种鳅科鱼类(短体副鳅Paracobitis potanini和红尾副鳅Paracobitis variegatus)幼鱼各放鱼90尾,定量分析鱼种、水体透明度、放鱼位置、流量、水温、水位等因素对鱼类下行效率的影响。结果表明:棒花鱼、短须裂腹鱼、短体副鳅、红尾副鳅的下行率依次为22.22%(20尾)、28.89%(26尾)、8.89%(8尾)、15.56%(14尾);幼鱼下行成功率与上游河道水温呈正相关趋势,且放鱼位置、鱼种、上游河道水温和流量均对鱼类下行成功率有显著影响。通过构建二元Logistic回归模型识...

Downstream migration of Juvenile fish at Songxin Hydropower Station on the Heishui River, lower reaches of Jinsha River

The development of cascade small hydropower to some extent destroyed river connectivity and hindered fish migration. Songxin fishway was built at Songxin Dam in the Heishui River Basin to meet the need for upward spawning of fish. However, as a key behavior in the life cycle of migratory species, the downstream migration of fish is equally important. In this study, the fish downstream dam-crossing effect was evaluated in the water-recharge channel of Songxin Hydropower Station on Heishui River, a tributary of Jinsha River, in order to seek a feasible, efficient and low-damage downstream fish-crossing method and to understand the influence of different environmental factors in the river on fish downstream efficiency. A total of 90 fish were released into each of the two cyprinid species (Abbottina rivularis, Schizothorax wangchiachii) and two cobitidid species (Paracobitis potanini, Paracobitis variegatus), and the effects of fish species, transparency, fish release site, flow, water temperature and water level on fish downstream efficiency were analyzed. The results showed that the descending rates of Abbottina rivularis, Schizothorax wangchiachii, Paracobitis potanini, Paracobitis variegatus were 22.22% (N=20), 28.89% (N=26), 8.89% (N=8) and 15.56% (N=14), respectively. The descending rate of juvenile fish was positively correlated with water temperature, and fish release site, fish species, water temperature and flow had a significant impact on the descending rate of fish. The binary Logistic regression model was constructed to identify the key factors affecting the downward efficiency of fish, and the optimal model was selected based on AIC criterion. The optimal model was based on fish release site, fish species, water temperature and flow. This study provided theoretical basis and technical support for river connectivity restoration, reservoir scheduling scheme and optimization design of downstream fish-crossing facilities under the background of cascade small hydropower.