Simulation of the effects of climate change and reduce irrigation requirements on groundwater recharge using SWAT and MODFLOW models

Improper extraction of groundwater resources has led to a sharp decline in the water level of aquifers. To achieve sustainable management of groundwater, it is very important to simulate the amount of recharging an aquifer by considering the physical properties of the relevant basin (such as soil properties, land use, irrigation, climate data and unsaturated layer). In the present study, a groundwater modeling was accomplished to predict the recharge rate under the conditions of climate change and irrigation reduction. Meteorological parameters in the next period (2021-2050) were simulated by ten climate change models (GCMs) under emission scenarios. The combination of SWAT and MODFLOW models was also used to predict the groundwater recharge rate. The results of forecasting climatic parameters in the next period (2021-2050) indicated that the temperature will increase (0.66-1.68 degrees C) while the precipitation will decrease (4-14%). The recharge rate modeling revealed that recharge values in heavy soils are less estimated compared to that of the light soils of the region. Also, the average recharge rate of the whole aquifer in the next period under the RCP4.5 and RCP8.5 scenarios will decrease by 23 and 34%, respectively. The simulation of reducing the irrigation requirements on the recharging rate indicated that with a 30% reduction of irrigation, the average recharging rate of the whole plain will decrease by 12%. Therefore, it is recommended to apply policies to decrease irrigation requirements, such as the development of pressurized irrigation systems and the cultivation of low-consumption plants, to help balance the aquifer.

Automated summary

Improper extraction of groundwater has caused water level decline in aquifers. This study simulates the recharge rate of an aquifer considering physical properties and predicts the effects of climate change and irrigation reduction. The results show temperature increase and precipitation decrease, and suggest reducing irrigation requirements to balance the aquifer.