Investigation of Groundwater Level Variations in Shahdad Aquifer

Numerical simulation of groundwater table variations can be an effective tool for water resources management. In this study, water table variations of Shahdad aquifer located in Kerman provience, were simulated using Groundwater Modeling System (GMS) software and MODFLOW model.Changes in the aquifer water level indicate a decrease in the aquifer in the northern, eastern, southern, and some central parts of the aquifer. The developed model was calibrated using the monthly water level measurements for the period of 2012-2013 and then validated using the monthly statistics for the water year 2015-2016. Aquifer properties including hydraulic conductivity, storage coefficient, and recharge rate were estimated by inverse modeling with PEST Code. The coefficient of determination for the validation stage was calculated as 0.95, demonstrating the good consistency of observed and predicted data and the ability of the model to predict future aquifer water table variations. A sensitivity analysis showed that the model is more sensitive to the well discharge than to surface recharge or hydraulic conductivity. Monthly reduction of discharge from wells by 30 percent can stop this phenamena.