Spatiotemporal estimation of land subsidence and ground water level decline in West Thessaly basin, Greece

Groundwater overexploitation in the Western Thessaly basin resulted to the generation of ground deformations. In order to investigate the mechanism of this phenomenon and of its future occurrences, data regarding the temporal variation of ground deformations and water level were examined and analyzed. They were collected from satellite Persistent Scatterer Interferometry measurements and several water wells, respectively. Based on the above data, the spatiotemporal correlation and cross-correlation of deformations and water level were considered. The modeled cross-variogram indicates a spatiotemporal correlation between the two variables, as would be theoretically expected. This correlation permits the application of cokriging to the deformations with water level as an auxiliary variable. Numerical results are more accurate compared with kriging, as indicated by the decreased estimation errors. The above statistical-based model approach will be useful for spatial interpolation at local and basin scale, while, for temporal estimations, medium-term predictions can be made.