This talk presents the review and characterization of land subsidence in Yunlin county, Taiwan. Long-term overexploitation of groundwater may be the primary factor causing regional land subsidence in western Taiwan. Currently, large subsidence funnels have moved from coastal areas to inland.

To clarifying and characterizing the possible causes of land subsidence, various methods based on the soil consolidation theory and the geographic information system spatial analysis are used. Temporal and spatial variations of land subsidence for the study areas are studied using the thematic maps including using the dynamic monitoring of groundwater level, remote sensing and hydrogeological data. The results depict that the spatial and temporal variations of land subsidence depend on the corresponding variations of groundwater extraction, coupled with the characteristics of sedimentary layers. Further studies are launched to give an insight into key issues including the contribution of different aquifer systems to land subsidence, the hydromechanical behavior of aquitards, and the regional-scale simulation of coupled groundwater flow and aquifer-system deformation.

By chkst26