Evaluation of natural carrying capacity and zoning of groundwater resources based on GIS

Natural carrying capacity of groundwater resources is closely related to natural attributes, and groundwater resource zoning is the important and basic work for evaluating the natural carrying capacity of groundwater resources. Based on the results of the recently completed national project of groundwater investigation as well as the latest survey and evaluation results of groundwater resources in the main plain or basins and a number of provinces (autonomous regions), this paper takes the surface water and groundwater as a whole, and divides the mainland areas into 26 first-level zones, 143 second-level zones and 412 third-level zones, according to a few indicators such as topography, geological structural unit, climate zoning, surface water basin and aquifer medium. The mainland areas are further divided into 4942 calculation units by combining groundwater resource zoning with county administrative areas. By using the exploitable modulus index, the evaluation results of the natural carrying capacity of groundwater resources are thus assigned to every counties, and a sound basis of spatial data of the natural carrying capacity of groundwater resources evaluation is set up, which can serve for the dynamic evaluation of carrying capacity of groundwater resources and support the rational utilization and management of groundwater. The evaluation results show that the natural carrying capacity of groundwater resources in China is medium-high level in plain basin area, and low-level in the arid areas in north China. There are 774, 332, 798, 387 and 573 counties (districts and cities) with high, mid-high, medium, mid-low and low levels, and the area accounts for 10.15%, 5.87%, 19.56%, 12.09%, and 52.34%, respectively. The results basically reflect the natural conditions and regional distribution of groundwater resources in China.