南水北调中线工程对河南平原第四系地下水资源的影响

INFLUENCES OF THE MID-ROUTE OF THE SOUTH-NORTH WATER DIVERSION PROJECT ON QUATERNARY GROUNDWATER RESOURCES IN THE HENAN PLAIN

南水北调工程是优化我国水资源配置、解决北方水资源短缺问题的重大举措。由于南水北调中线工程的调蓄作用,河南省受水地区水源结构的改变对主要的供水水源第四系地下水资源势必造成一定的影响。论文在建立河南平原地下水流数值模型的基础上,按照受水区的分配水量相应压采各城市的浅层地下水开采量,模拟预测南水北调中线工程实施后第四系地下水流系统的演化趋势。预测结果表明:河南平原受水区浅层地下水位都得到了不同程度的恢复,到2010年,郑州市、新乡市、濮阳市漏斗中心水位相比南水北调中线工程实施前(2007年1月1日)将分别提高6.64m,8.15m和4.15m,很大程度上减轻了地下水的开采压力,有效地恢复了地下水位降落漏斗,缓解了当地水资源的供需矛盾;但是由于农业灌溉超量开采地下水,河南平原中部和东部的非受水区浅层地下水位仍持续下降;南部尽管不在受水区范围内,但是供水水源主要来自地表水,所以浅层地下水位无明显变化。结合前人的供需水量预测结果,到2010年,南水北调中线工程分配给受水区的水量与受水区的需水量基本持平。

The South-North Water Diversion Project was put forward for optimizing the national allocation of water resources and solving water shortage problems in Northern China. With the reservoir action of the mid-route of the South-North Water Diversion Project, which will resulted in transfer of water from groundwater to surface water in the water-received areas, the main water supply source, Quaternary groundwater resources in the Henan plain,would be influenced in the future. Through establishing a groundwater flow numerical simulation model, this paper simulated the effect of the project on Quaternary groundwater of Henan plain by correspondingly decreasing the exploitation quantity of the shallow groundwater in water received areas according to the allocated water quantity. The simulating results indicate that the water level of the shallow groundwater would be restored in some degree in the water received areas. By 2010 ,for example,in the centers of the groundwater depression funnels of Zhengzhou, Xinxiang and Puyang, the water level would be increased by 6. 64m, 8.15m and 4. 15m, respectively, compared with that before 1 January, 2007 when beginning of the project. Therefore, this project would greatly decrease the exploitation of groundwater and alleviate the pressure of water shortage. However, the water level of shallow groundwater in the water non-received areas of the middle and east of the Henan plain would decline continuously as a result of groundwater over-extraction for agriculture irrigation. In spite of being out of the water-received area, the southern would be constant in water table, which can be explained by that local water supply is mainly from surface water. Combined with results of previous researchers, it can be predicted that the amount of water allocated to water-received areas by the project to be equal to their demand by 2010.