A Two-Dimensional Numerical Model of Groundwater Flow in Safwan AlZubair Area, South of Iraq

Abstract

A two-dimensional model was developed to simulate the unsteady state flow of groundwater in the upper part of Dibdibba sandy unconfined aquifer in Safwan-Zubair area, south of Iraq,in order to assess the hydraulic characteristics in this aquifer by the comparison of the observed head and calculated head, as well as the use of this model to predict the groundwater head in case of changing weather conditions. The suggested conceptual model, which is advocated to simulate the flow regime of aquifer, is fixed for one layer, i.e. the activity of the deeper aquifer is negligible. Seven cases were considered during sensitivity analysis. The results of sensitivity analysis showed that the increment of the initial values of hydraulic conductivity (K) and specific yield (Sy) more than 100% can lead to a noticeable increment in the level of groundwater.The unsteady state calibration results were evaluated by comparing the temporal variation in simulated heads with those of observed ones at thirteen observed wells.According to the calibration process, the hydraulic characteristics of the upper aquifer have been redistributed; the hydraulic conductivity in the study area was between (15-150) m/day, while the specific yield was between (0.125-0.45).