Modelling the effect of water fall in the river level on unsteady groundwater flow in leaky aquifer by separation of variables

In order to model groundwater flow, numerical and analytical methods can be utilized. In this paper, the effects of different parameters on leaky aquifer were investigated using mathematical model and separation of variables method. This aquifer is located adjacent to the river and the flow rate falls across the border. Comparison of hydraulic head changes shows that over the time the water level changes decreases in the aquifer and the aquifer adapts itself to the new conditions. Groundwater level decrease with rises in hydraulic conductivity. Reducing hydraulic conductivity has a greater effect than increasing it on the aquifer. Also, the groundwater head rises by increasing the recharge rate and over time, these changes are more evident. Outflow changes are greater than inflow changes. In addition, the presented analytical solution is compared with those results obtained from MODFLOW. This comparison showed that the analytical solution presented in this research is very efficient.