基于生态水位的张掖盆地地下水合理开发研究

Study on Reasonable Groundwater Exploitation Based on the Ecological Water Level in Zhangye Basin

针对黑河流域上下游水资源矛盾,中游张掖盆地地下水位持续上升的现象,设计增加地下水开采量的解决方案。首先对张掖盆地地下水生态水位进行了理论探讨,将张掖盆地分为山前倾斜平原区和中部细土平原区,在山前平原地带地下水位埋深应控制在10 m之内,以便发挥地下水含水层的调蓄能力;中部平原生态水位的上限是防治地表土壤盐渍化的水位,埋深为3 m,下限是防止地表植被退化的水位,埋深为5 m。然后根据各灌区当前情况设计地下水可持续开采量3.6亿m3,采用数值模拟方法对研究区的地下水位进行模拟和预测,并依据研究区合理生态水位证明了设计开采方案的合理性。

According to the water resources contradiction between upstream and downstream of the Heihe River basin, and the groundwater level of Zhangye basin in the midstream rising continuously, this paper designed a solution scheme about increasing groundwater extraction. Firstly, it made theoretical discuss on the ecological groundwater level of Zhangye basin. Secondly, it divided the basin into two parts, i.e. the tilt piedmont plain area and central fine soil plain area. Thirdly, it controlled the groundwater level within the range of 10 meters in the piedmont plain area to exert the regulation and storage capacity of groundwater aquifer. Meanwhile, it controlled the ecological level in the central plain area between 3 meters and 5meters, where the upper limit is threshold of preventing soil salinization and the lower limit is threshold of preventing the surface vegetation degradation. Then according to the current situation of each irrigation district, the designing groundwater sustainable exploitation amount is 0.36 billion m3 , and the exploiting scheme is reasonable by making simulation and prediction on groundwater level of research area through numerical simulation and the reasonable ecological level of research area.