Management of Planning for the use of unconfined aquifer by using GMS model

Exploitation, management and protection of water resources, especially groundwater resources, are very important. The management of water resources requires accurate knowledge of the characteristics of the aquifer, the tension to it and finally the groundwater balance. Simulation models help planning managers to determine the amount of aquifer utilization for long-term and sustainable use. For this purpose, changes in the water level of the Kashan plain aquifer in the statistical period of 1387-1397 were simulated by the GMS model for 125 stress periods. The model was calibrated in two permanent and non-permanent modes for a period of 94 months (1387-1395) and validated for a period of 31 months (1395-1397).The result was a drop of 4.4 meters of groundwater during the 10-year study period. To predict the behavior of the aquifer in the near future, the reservoir level was modeled until 1407. Due to the location of this plain in the climatic dry belt and the occurrence of climate change and the lack of effective rainfall to properly charge the aquifer, in this study the focus was on the management of extraction from the aquifer and according to these three scenarios, extraction with the current trend,15% increase and 15% reduction definition and simulation was done. The simulation results of these three scenarios showed a drop of 9.866, 11.895 and 6.993 meters at the end of 1407 respectively.