Multiple sensors applied to monitorland subsidence in Central Taiwan

W.-C Hung,C Hwang,Y.-A Chen,H.-C Chiu,S.-H Lin,C Wang

doi:10.5194/piahs-372-385-2015

Abstract

Abstract. During 1992–2013, pumping of groundwater caused large-scale aquifer-system compaction and land subsidence in the Choshui River Alluvial Fan (CRAF) in Taiwan. The subsidence has already endangered the operation of Taiwan High Speed Rail (THSR). In this paper, we introduce the multiple sensors monitoring system to study the extent of subsidence in CRAF and its mechanism, including GPS (Global Positioning System), PSI (Persistent Scatterer Interferometry), leveling and multi-layer compaction monitoring well. These sensors complement each other in spatial and temporal resolutions.

Highlights

Due to continuous growth of the population and economy, more water resources are needed
In order to further investigate the mechanism of land subsidence, the multi-sensors monitoring system including In
In addition to the Taiwan High Speed Rail (THSR) leveling network, a leveling network west of THSR was established by Water Resource Agency (WRA) of Taiwan to monitor surface subsidence in Yunlin County

Summary

Introduction

Due to continuous growth of the population and economy, more water resources are needed. The underground water resources will no longer be utilized. These problems will result in the increase of the social cost. Excessive exploitation of the underground water is common in the country areas. Because the upstream watershed area of Choshui River is wide and infiltrative, surface water in the head of the fan will penetrate the ground to recharge the subsurface aquifers. Due to the lack of surface water and the flat terrain that prohibits dam construction, the water for civilian and agricultural use in CRAF comes largely from underground. According to the statistics of Water Resource Agency of Taiwan, the extracted groundwater in Yunlin is 94 metric tons a day, totaling 305 million tons a year. The Taiwan High Speed Rail (THSR) passes through Yunlin, where subsidence poses a serious threat to its operation (Hung et al, 2011)

Synergy of monitoring sensors

Leveling

Continuously operating reference stations

Multi-layer compaction monitoring well

Discussion and conclusions