3D GEOMECHANICAL ANALYSIS OF LAND DISPLACEMENTS DUE TO AQUIFER OVER-EXPLOITATION IN THE GEDIZ RIVER BASIN,TURKEY

The alluvial aquifer system of Gediz River basin, western Turkey, has been largely over-exploited during the last decades mainly for crop production. The lowering of the piezometric levels following groundwater pumping has caused significant land subsidence, up to a few centimeters per year. The thesis work is aimed at using the GEPS3D simulator, which is a three-dimensional geomechanical model developed at Dept. ICEA of Padova University, to simulate the displacement fields in the study area over the last 8 years. The factor forcing the aquifer deformation is represented by the pressure evolution has reconstructed in Dokuz Eylul University, Turkey, using MODFLOW. The results revealed that the highest land subsidence which was obtained in the range of 4 m. During the whole simulation period land subsidence reduced to 3.2 m. The study also evaluated the horizontal displacement and change of displacement components over time due to pressure fluctuation.