梯级枢纽条件下信江下游四大家鱼繁殖期水文情势分析

Hydrological Regime Analysis of Breeding Period for Four Major Chinese Carps in Downstream of Xinjiang River After Cascade Junction Operation

为探究梯级枢纽建设及运行对信江下游四大家鱼产卵场水文情势的潜在影响,选取21项参数建立鱼类产卵场水文评价指标体系,采用一维水动力模型分析了大溪渡产卵场河段在梯级枢纽建设前后的水文情势,并采用变动范围法分析了梯级枢纽建设前后产卵场繁殖期生态水文变化情况。结果表明,四大家鱼繁殖期流量在枢纽运行后呈下降趋势,研究区域断面流量趋于平均;高流量脉冲数量减少,降低了脉冲流量对四大家鱼产卵的刺激性信号。研究量化了信江下游梯级枢纽建设对库区内产卵场繁殖期生态水文的影响,为当地枢纽调度运行的方案设计提供科学指导。

To analyze the potential influence of the construction and operation of the cascade junction on the hydrologic regime of four major Chinese carps spawning sites in the downstream of the Xinjiang River,21 parameters were selected to establish the hydrological index system of fish spawning sites.The one-dimensional hydrodynamic model was adopted to analyze the hydrological regime of Daxidu spawning site before and after the construction of the cascade junction.The range of variability approach was used to analyze the hydrological changes of spawning grounds during the breeding period before and after the construction of cascade junction.The results show that the flow during the breeding period decreases after the operation of the cascading junction,which made the variation range of water flow limited in a small range.Furthermore,the number of high flow pulse decreased,which reduced the stimulation signal to spawning of four large fishes.This study quantified the impact of the construction of cascade junction in the downstream of the Xinjiang River on the spawning grounds during the breeding period,and provided scientific guidance for the design of the local hub operation scheme.