Using a finite element model for optimizing the pumping rates from an overpumped aquifer in Dhuleil-Hallabat area-Jordan

الملخص EN

The groundwater regime of the Basalt Aquifer of the Dhuleil-Hallabat area for the period 1965-1992 was analyzed using a finite-element model (Istok, 1989).

During this period, the observation wells of the aquifer had shown considerable drawdown in the water table as a result of extensive overpumping of the aquifer.

In order to select an optimum pumping scenario, a two-dimensional finite-element model was constructed to simulate the groundwater flow in the aquifer system and to examine the response of the aquifer to various groundwater abstraction scenarios.

The optimum plan was selected in a way to recover the drawdown in the groundwater table gradually over a period of time by considering the safe yield of the aquifer.

Steady-state and transient calibration were performed, until simulated and measured responses of the aquifer through the monitored period matched.

After demonstrating the validity of the model, the model was used to predict the future water level changes that would result from the implementation of four different abstraction scenarios including the optimum one.

The results of the model have shown that the current pumping rate exceeds by a factor of two to three the sustainable one.

The current abstraction rate, according to WAJ’s data, is about 30 MCM/yr (annual recharge is about 11 MCM) for various uses where the optimum scenario indicates a pumping level of about 12 MCM/yr to maintain the sustainability of the aquifer yield.