Evaluation of changes in groundwater level of Jafaria plain using GMS software and MODFLOW Code

Jafarieh plain is part of Salt Lake watershed that is experiencing a crisis due to drought and excessive use of groundwater resources, so it is necessary to study groundwater, which is the main source of water in the whole plain. This study aimed to model the MODFLOW code of Jafarieh plain aquifer in GMS software as an efficient model in groundwater issues. The quantitative model of the Jafarieh aquifer was simulated over two ten-year statistical periods(1992-2002 and 2002-2012) using the water level statistics of the piezometric wells in the study area, and model calibration was performed in both steady and non-steady states. Finally, the model was validated with observational data. The results showed that the model is most sensitive to changes in groundwater recharge, and the average aquifer loss in the years 1992 to 2002 was from 0.05 to -1.5 m. So, the highest decline occurs in the eastern part of the study area. Also, the average aquifer loss in the period 2002-2012 has decreased from -0.26 to -7.2 m, indicating that the aquifer has declined more strongly during this period, with the highest decline in the northwest and southeast regions. Its consequence is the annual decline of 0.73 meters seen in these two-10-year periods in the region.