Integrations of multiple observations to estimate hydraulic parameters in choushui river fluvial plain of central taiwan

Choushui River Fluvial Plain (CRFP) located in central Taiwan is composed of deposited sediment. Based on observations from 1970s, CRFP has threatened by serious pumping-induced land subsidence. Precise geodetic measurements such as differential leveling, GPS, and InSAR are useful for observing the land deformation. However their accuracy and spatiotemporal resolution are quite different. Specifically, differential leveling data give the basis of spatially accurate measurements of land subsidence, GPS data provide relatively high temporal observations, and InSAR techniques provide high spatial resolution but the available images are limited. In this study we employed geostatistical analysis techniques to estimate the spatial variogram of observation data and used curve-fitting method to integrate the data with temporal scale. Based on the results of the integrated observations we used consolidation equations from well-known SUB program to estimate the aquifer hydraulic parameters in CRFP. The results showed that the spatial variability in direction 30° and 90° (from north) are higher than other directions. The estimated inelastic skeletal specific storage (Sskv) is 4 × 10^–3 (1/m) and vertical hydraulic conductivity (Kv) is 2.6 × 10^–3 (m/day). The root mean square error of the simulation and observation data reaches 2.58 × 10^–2 (m).