基于四大家鱼产卵需求的汉江中下游生态流量研究

针对汉江中下游梯级电站开发后水文节律变化造成四大家鱼栖息地生境质量降低的问题，分别通过几种常用水文学法和栖息地模型计算了汉江中下游河道最小生态流量和四大家鱼产卵适宜生态流量，并在最小生态流量的基础上，结合四大家鱼产卵适宜生态流量以及生态水文特征在5-8月进行了脉冲设计，综合确定出了满足四大家鱼产卵需求的生态流量过程。结果表明，Lyon法和7Q10法最适宜汉江中下游最小生态流量的计算，流量为294~863 m3/s；通过栖息地模型计算，彭市和仙桃江段四大家鱼产卵适宜生态流量为1233~3950 m3/s；流量日涨幅在139.1~534.8 m3/s，持续5 d的涨水过程可为四大家鱼产卵提供良好的条件。该研究从考虑四大家鱼产卵需求的角度，为汉江中下游梯级电站的生态调度提供科学参考。

Ecological Flow in the Mid-lower Hanjiang River Based on Spawning Demands of the Four Major Chinese Carps

The hydrologic regime and ecology of the middle and lower Hanjiang River have changed dramatically due to cascaded hydropower development. Ecological flow is fundamental to river habitat health and important for fish resource restoration. In this study, we obtained hydrological data for the Pengshi and Xiantao reaches from 1960 to 2018 and calculated the minimum ecological flow using four common methods. Then, the optimal ecological flow for spawning of the four major Chinese carps was estimated using a habitat model. Finally, the ecological flow necessary to meet spawning requirements of the four major Chinese carps was comprehensively determined by incorporating the pulse design from May to August (based on the minimum ecological flow), the optimal ecological flow, and the eco-hydrological characteristics that promote spawning. Results show that the Lyon and 7Q10 hydrological methods were most suitable for calculating the minimum ecological flow in the mid-lower Hanjiang River, and that the calculated minimum ecological flow ranged from 294-863 m3/s. Based on habitat model calculations, the optimal range of ecological flow for spawning of the four major Chinese carps in the Pengshi and Xiantao reaches was 1 233-3 950 m3/s. If the daily increase in flow is in the range of 139.1-534.8 m3/s, over a 5 day period, the flow regime will provide favorable spawning conditions for the four major Chinese carps. This study provides a scientific reference for conserving the four major Chinese carps and optimizing the ecological regulation of cascaded power stations in the mid-lower Hanjiang River.