Steady-State Unconfined Aquifer Simulation of the Gareh-Bygone Plain, Iran

The first step of aquifer parameter and dependent variable estimation based on hydraulic modeling is generally to choose the best steady-state condition for the set time period. In order to define the best estimated hydraulic conductivity and boundary condition for Gareh-Bygone Plain in arid southern Iran, ten different steady-state conditions were simulated and calibrated with limited field observations. The investigated area covers about 6000 ha with a floodwater spreading system that was established on about 2000 ha to artificially recharge the groundwater. The results showed a consistency over the 14-year simulation period with estimated hydraulic conductivity in a quite narrow range. This makes us believe that even if the modeling problem is to some extent over-parameterized the results appear quite robust. This is further strengthened by verification of the model results. Furthermore, the results showed that in the steady-state groundwater flow with no recharge from surface water, the system is mainly recharged by the fault which conducts water into the area from an upper sub-basin.