Groundwater-pumping optimization for land-subsidence control in Beijing plain, China

Beijing, in the North China plain, is one of the few megacities that uses groundwater as its main source of water supply. Groundwater accounts for about two-thirds of the city’s water supply, and during the past 50 years the storage depletion from the unconsolidated aquifers underlying the city has been >10.4 billion m³. By 2010, groundwater pumping in the city had resulted in a cumulative subsidence of greater than 100 mm in an area of about 3,900 km², with a maximum cumulative subsidence of >1,200 mm. This subsidence has caused significant social and economic losses in Beijing, including significant damage to underground utilities. This study was undertaken to evaluate various future pumping scenarios to assist in selecting an optimal pumping scenario to minimize overall subsidence, meet the requirements of the Beijing Land Subsidence Prevention Plan (BLSPP 2013–2020), and be consistent with continued sustainable economic development. A numerical groundwater and land-subsidence model was developed for the aquifer system of the Beijing plain to evaluate land subsidence rates under the possible future pumping scenarios. The optimal pumping scenario consistent with the evaluation constraints is a reduction in groundwater pumping from three major pumping centers by 100, 50 and 20%, respectively, while maintaining an annual pumping rate of 1.9 billion m³. This scenario’s land-subsidence rates satisfy the BLSPP 2013–2020 and the pumping scenario is consistent with continued economic development. It is recommended that this pumping scenario be adopted for future land-subsidence management in Beijing.