考虑齐口裂腹鱼产卵需求的山区河流生态基流过程确定

在原型观测的基础上,应用生态水力学法与生境模拟法,建立对考虑齐口裂腹鱼产卵需求的山区河流水电工程生态基流过程的确定方法,并以四川中型山区河流杂谷脑河薛城电站为背景,对所构建方法进行应用分析。通过原型观测,对生态水力学的齐口裂腹鱼生境水力参数标准在杂谷脑河应用的适宜性进行分析;应用生态水力学方法,对不同河道流量下薛城电站减水河段的齐口裂腹鱼生境水力参数进行数值模拟,根据模拟结果,结合齐口裂腹鱼生境水力参数标准,分析得到薛城电站满足其生存的最小下泄流量;应用生境模拟法,对齐口裂腹鱼产卵期不同河道流量下薛城电站减水河段集中产卵场的可利用生境面积进行计算,得到最大可利用生境面积对应的下泄流量。综合最小下泄流量值与最大可利用生境面积所对应的下泄流量值,考虑齐口裂腹鱼产卵对水文情势的要求,建立薛城电站考虑齐口裂腹鱼产卵需求的生态基流过程。采用所构建方法得到的考虑鱼类产卵需求的水电工程生态基流过程,由于考虑了鱼类生存对最低流量以及产卵对水文情势的要求,能更好地满足鱼类产卵需求,可作为电站运行调度的约束。

DETERMINATION OF ECOLOGICAL BASE FLOW PROCESS OF MOUNTAINOUS RIVERS BY TAKING INTO ACCOUNT THE PRENANT'S SCHIZOTHORACIN'S SPAWNING REQUIREMENTS

For the purpose of protecting fishes, the ecological base flow process of hydropower projects on mountainous rivers was studied by taking into account the Prenant's schizothoracin spawning requirements. On the basis of prototype observation and by using the ecological hydraulic method and habitat simulation method, the determination method of this kind of ecological base flow process was established. The established method was applied and analyzed by using the Xuecheng Hydropower Station on the Zagunao River as the background which is a medium mountainous river in Sichuan Province. By using the prototype observation method, the suitability of the standards for hydraulic parameters of fish habitats was analyzed. By using the ecological hydraulic method, the hydraulic parameters of fish habitats at the water reducing reach of the Xuecheng Hydropower Station at different flow rates were numerically simulated. In this paper, 11 conditions were taken into consideration, including a site investigation condition and 10 simulation conditions of different flow conditions. The investigation reflected hydrological conditions and habitat characteristics of actual situation, and provided a comparison to simulation conditions. And the concentration of spawning period of fish was selected as the investigation period. According to the simulation results and in combination with the standards for hydraulic parameters of fish habitats, the minimum discharge volume for the survival of fishes in the Xuecheng Hydropower Station was obtained. The minimum discharge volume was 17.43 m³/s, if the flow is lower than this number, the quality of fish habitat would be affected. By using the habitat simulation method, the available habitat area of the centralized spawning site in the water reducing reach of the Xuecheng Hydropower Station at different flow rates during the spawning period was calculated, and the discharge volume corresponding to the maximum available habitat area was obtained. When the peak flow in river coursed at 20.91 m³/s, the WUA of fishing spawning area in the Xuecheng Hydropower Station would be maximized. When the flow was less than 20.91 m³/s, the WUA would reduce. By integrating the minimum discharge volume and the discharge volume corresponding to the maximum available habitat area and by considering the requirements of hydrological regime required by spawning, the ecological base flow process required for the spawning was established for the Xuecheng Hydropower Station. Due to the consideration of the requirements of minimum flow rate by fish survival and the requirements of hydrological regime by spawning, the established ecological base flow process of hydropower projects which takes into account the spawning requirements can better meet the spawning requirements of fishes, and can be used as the constraints for the operation and dispatching of a hydropower station.