摘要
金沙江下游梯级水电开发导致下游水温沿程变化,对鱼类产卵繁衍和生长发育产生了重要影响.基于下游向家坝、朱沱、宜昌和大通4个水文站2002-2022年表层水温监测数据,对比分析了梯级水电建设期、运行期下游江段水温沿程的变化规律.结果表明:①溪洛渡和向家坝两级水电联合运行期,向家坝水文站多年平均最低水温较天然状态升高约1.4℃,最低水温出现时间较天然状态滞后约35 d;②乌东德、白鹤滩、溪洛渡和向家坝四级水电站联合运行期,向家坝、朱沱、宜昌和大通4个水文站年最低水温分别较溪洛渡和向家坝两级水电站联合运行期升高约2.0、1.1、0.8、0.7℃,年最低水温出现时间较天然状态分别滞后约42、29、11、18 d.研究成果可以为金沙江下游梯级水电站水温生态调度和下游水生态保护提供参考依据.
Abstract
The cascade hydropower construction along the Jinsha River has altered downstream water temperatures,significantly impacting fish reproduction and growth.Utilizing surface water temperature monitoring data spanning from 2002 to 2022 at Xiangjiaba,Zhutuo,Yichang,and Datong hydrological stations,we compared the variations in water temperature downstream of the cascade reservoirs between construction period and operational period.Our findings reveal that:1)During the two-stage joint operation of Xiangjiaba and Xiluodu hydropower stations,the an-nual minimum water temperature at Xiangjiaba hydrological station rose by 1.4 ℃,with the occurrence of the lowest water temperature delayed by 35 days compared to natural conditions.2)Subsequent to the construction of Wudong-de and Baihetan hydropower stations and the shift to four-stage joint operation,the lowest water temperatures at Xiangjiaba,Zhutuo,Yichang,and Datong hydrological stations increased by 2.0 ℃,1.1 ℃,0.8 ℃,and 0.7 ℃,respectively,compared to the two-stage operation period.Additionally,the occurrence of the lowest water tempera-ture with four-stage operation was delayed by approximately 42 days,29 days,11 days,and 18 days,respectively.These results offer valuable scientific support for managing water temperatures in cascade reservoirs and safeguard-ing downstream eco-environments.
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万方数据