Numerical groundwater modeling and scenario analysis of Beijing plain: implications for sustainable groundwater management in a region with intense groundwater depletion

Groundwater serves as one of the crucial natural resources in the safety and sustainable development of Beijing economy. Due to the fact that Beijing is one of the megacities with groundwater as the main water source, it abstracts two-thirds of the city's water supply from groundwater. Meanwhile, the groundwater aquifer storage depletion has been larger than 1.04 x 10(10) m(3) during the past decades, which has brought serious eco-environmental problems to Beijing. The purpose of this study is to evaluate various abstraction schemes using a 3-D transient numerical groundwater flow model, to understand the present situation and future trend of groundwater resources in Beijing plain. The sustainable utilization of groundwater under these scenarios was comprehensively analyzed. The most reasonable scenario, which meets the appraisal restraint conditions, is the one that the groundwater extraction volumes of the three subsidence centers are reduced by 50%, 20%, and 100%, respectively, with the groundwater abstraction rate of 1.769 x 10(9) m(3)/year. Countermeasures that could be considered to improve sustainable groundwater management include: reducing groundwater abstraction directly; importing surface water from outside river basins; improving agricultural water use efficiency; and controlling the groundwater abstractions in the subsidence centers. The results of the modeling study could be used to inform policymakers and the government of Beijing.