Generating strategies for land subsidence control and remediation based on risk classification evaluation in Tianjin, China

Abstract

Land subsidence caused by excessive groundwater extraction is a manmade geological hazard caused during the development of many cities. It is fundamental for the management department to conduct targeted optimal control and remediation strategies according to formation conditions and specific control factors of land subsidence. In this study, we evaluated the risk of land subsidence in Tianjin by evaluating three aspects: hazard level, susceptibility, and potential consequences of land subsidence. The results showed that the areas with minor, moderate, considerable, and severe risks accounted for 56.3%, 21.2%, 19.5%, and 3.0% of the total area, respectively. Based on the characteristics of the risk classification distribution and factors affecting land subsidence in each administrative district, strategies for controlling and remediating land subsidence in each administrative district are proposed. Each district's strategy is a combinatorial countermeasure, including implementing artificial groundwater recharge, giving priority to the use of externally transferred water sources, exploitation control of different groundwater layers, promotion of the application of water-saving technologies for facility agriculture, and adjustment of agricultural planting structures. The research results are essential in guiding Tianjin's control and remediation of land subsidence in the future and have reference value for cities suffering from land subsidence disasters caused by excessive groundwater extraction.