水利工程对汉江中下游水文生态的影响

Impact of hydraulic engineering on hydro-ecology in middle and lower reaches of Hanjiang River

主要采用1980年以前的数据资料,分析丹江口水库建成后对汉江中下游径流量、泥沙、水温、水质、鱼类等的影响。结果表明:水库运行使汉江中下游水量减少,流量过程均化;防洪能力提高;泥沙大量减少;汛期水温降低;鱼类资源减少;水质没有明显的变化。汉江中下游水质恶化和发生水华的主要原因是污染增加。南水北调中线工程建成运行后,汉江中下游江段流量将比现状大幅度减少,流速变缓,对水污染的稀释自净能力降低,生态环境可供水量不足,使水文生态朝着不利的方向发展。

According to observed data before 1980, the impacts＇of the operation of Danjiangkou Reservoir on runoff, sediment, water temperature, water quality, and fish were studied. The results showed that the operation of the reservoir had reduced water quantity and homogenized annual runoff distribution, improved the flood control level, reduced sediment and water temperature during the flooding period, and reduced fish resources, and had no apparent influnce on water quality. The reason for worsening water quality and algal blooms in the middle and lower reaches of the Hanjiang River was increasing water pollution. After the South-to-North Water Transfer Project is built and in operation, runoff will be reduced much more, as will the water flow velocity. These will reduce the dilution and self-purification ability of water and the eco-environmental water supply, and lead the hydro-ecology in a negative direction.