The Evaluation of Groundwater Carrying Capacity in Xi'an

With the development of the economy and society, the importance of water as a necessary resource has increased. The resource attribute capacity of groundwater is limited, and excessive consumption depletes groundwater resources. The extremely serious and highly integrated groundwater problem necessitates the determination of the carrying capacity of groundwater resources. Based on the research findings of the carrying capacity of groundwater resources in China and other parts of the world, in this study, we proposed a new method to determine the carrying capacity of groundwater resources. We evaluated the carrying capacity of groundwater resources in Xi'an by using the probabilistic neural network method based on the 'W-F extension law'. The results showed that the extremely low and low bearing capacity areas of groundwater in Xi'an are located in the southern plain area of Zhouzhi county and Huyi district, the southern suburbs of Xi'an city, and the loess platform source area. Due to the constant supply from the riverside water source, the groundwater associated with the Bahe river, Fengzaohe river, and Weibin water sources have a higher bearing capacity than other evaluation areas. Compared to the traditional evaluation method, in this study, we redefined the evaluation index standard of the carrying capacity of groundwater. The groundwater carrying capacity is only related to groundwater and its storage medium. The pressure index of groundwater carrying, such as the population, economy, and environment in the traditional evaluation method, is considered overexploitation. The interaction between surface water and groundwater can be distinguished, and the level limit of the evaluation index can be determined more accurately. Additionally, the probabilistic neural network method of the 'W-F extension law' does not allocate weights but calculates the clustering center. Thus, to avoid subjectivity, parameter weighting is not required. This method does not have regional restrictions and can reflect the non-linear relationship of the groundwater system. It can reflect the sensitivity and recovery ability of groundwater under the same future exploitation load. The evaluation results of this method were consistent with the evaluation results of the third groundwater resources survey in Xi'an in 2019, and the evaluation results were very similar to the actual situation. The accuracy and practicability of the evaluation method were verified.