Multi-sensor System for Detecting Land Subsidence in Central Taiwan

During 1992-2022 excessive withdrawal groundwater caused large-scale aquifer-system compaction and land subsidence in the Choshui River Alluvial Fan (CRAF) in Taiwan. How to effectively monitor land subsidence has become a major issue in Taiwan. In this paper, we introduce a multiple-sensor monitoring system for detecting land subsidence in central Taiwan, including 46 continuous operation reference stations (CORS), multi-temporal InSAR (MT-InSAR), a 1000-km leveling network, 36 multi-layer compaction monitoring wells, 7 automatic record extensometers, and 223 groundwater monitoring wells. This system can monitor the areal extent of land subsidence and provide data for studying the mechanism of land subsidence. We also develop new low-cost high-performance GNSS equipment and automatic multi-layer compaction monitoring equipment to monitor different aquifer compaction. We also use the Internet of Things (IoT) technology to control and manage the sensors and develop a big data processing procedure to analyse the data from the system of sensors. The procedure makes land subsidence monitoring more efficient and intelligent.