Numerical Simulation of Bijar-Divandere Plain Aquifer Using MODFLOW Code and Investigation in The Effects of Drought on Its Quantitative Changes

In this study, quantitative changes in groundwater in Bijar-Divandere plain with MODFLOW code in GMS software were investigated. Aquifer simulation was performed for a period of six years and a monthly step from October 2010 to June 2016. The SPI annual drought index was calculated for the statistical period of 1987-2015. The results of groundwater simulation showed that during the annual simulation period, there was a decrease of about 0.5 m water level in the aquifer, the intensity of which varied in different areas. Therefore, due to the decrease and taking into account the area and the average amount of storage capacity of the aquifer, the volume of the aquifer has been reduced by about 1.3 MCM per year. The results showed that if the current management process continues, over the next few years we will see a sharp decline in the aquifer and irreparable damage. The results of SPI index also indicated that the drought situation was close to normal, which means that drought has a much lesser effect on the groundwater level of the aquifer in different years.