Present situation and research prospects of the land subsidence driven by groundwater levels in the North China Plain

The North China Plain (NCP) has the greatest area of severe land subsidence, accounting for more than 80% of the total area of severe land subsidence in China. The situation of prevention and control of land subsidence is urgent. Targeted researches are needed to carry out to provide scientific basis for effective prevention and control of land subsidence. A relatively complete land subsidence monitoring network is established in the NCP, and the current status and evolution of land subsidence are basically grasped. However, due to the limitation of the complex influencing factors and large variation in time and space of aquifer systems, the researches on groundwater-derived deformation characteristics and mechanism of soil layers are relatively weak so far, restricting the scientific evaluation of the development trend of land subsidence and its forecast and early warning. Based on summarizing the research progress of land subsidence at home and abroad, and analysing the current situation and development trend of land subsidence in the NCP with monitoring data of high temporal and spatial resolutions, the research directions of land subsidence under the influence of groundwater level changes are proposed. The land subsidence in the NCP was alleviated, and was effectively controlled in the downtown areas of the major cities such as Tianjin, Cangzhou and Hengshui. However, on the whole, the land subsidence in the NCP, especially in the Hebei Plain, is still in a relatively rapid development stage, because the exploitation of groundwater in the agricultural irrigation areas cannot be effectively controlled. Future researches on land subsidence in the NCP should focus on the land subsidence mechanisms and prediction and early warning, the law of soil deformation driven by groundwater level rise and its impact on the environment, the attributes of groundwater resources in the subsidence areas, and the relationship between geothermal development and land subsidence.