Integrating the impact of large-scale hydraulic engineering with a sustainable groundwater development strategy: A case study of Zhengzhou City, China.

With the rapid growth of China's economy, the increase in water demand has threatened the sustainable development of groundwater. Construction of the South-to-North Water Diversion Project alleviated this problem. Zhengzhou, with a large population and high-intensity energy consumption, is a water-receiving city of the South-to-North Water Diversion Central Line Project (CLP). A series of ecological risks caused by the excessive exploitation of groundwater have been exposed. It is urgent to strengthen the assessment and management of groundwater to ensure sustainable development. In this study, the multi-criteria decision analysis (MCDA) underpinned the assessment of the sustainable groundwater development (ASGD) framework. Eight assessment factors were established based on the resource supply function (RSF) and eco-environment stability function (ESF). The novelty of this study lies in the integration of ASGD results with the impact of the CLP on the evolution of groundwater levels in Zhengzhou. Thus, more comprehensive and scientific management suggestions for groundwater development in Zhengzhou were obtained. GIS technology was integrated with the ASGD framework to identify five visualized areas: centralized groundwater supply area (8.61%), decentralized groundwater supply area (27.91%), vulnerable eco-environment area (14.34%), recharge protection area (45.67%), and unsuitable exploitation area (3.47%). The CLP changed the groundwater evolution pattern in Zhengzhou. The results showed that the operation of the CLP effectively slowed the decline in groundwater levels, thus confirming that the CLP has a positive impact on the rational utilization of groundwater. The disuse of two groundwater sources (G1 and G9) were able to enhance sustainable groundwater development. Meanwhile, five groundwater sources in the plain area proved unsuitable. Overall, this study provides a scientific basis for groundwater management in Zhengzhou City, while generating new ideas for sustainable groundwater development in cities affected by large-scale hydraulic projects worldwide.