Applying Modflow to Simulate Groundwater Flow in EL - Farafra Depression, Western Desert, Egypt / S. H. Moharram

Farafra oasis is located in the central part of west desert, Egypt. It is an arid area with very limited resources relative to demand. Groundwater is the main source for its water supply. During recent years, water resources of the oasis have been encountered with problems due to overgrowth of exploitation establishments and agricultural processes. Thus, to evaluate the existing situation and managing a good usage of water resources, MODFLOW was used to simulate the groundwater behavior of Nubia Sandstone Aquifer System in El-Farafra Depression (NSAS-FD). The calibration of the model parameters was conducted under steady and transit state conditions using the available data of 48 wells. Based on the MODFLOW model, three appropriate scenarios were proposed for a sustainable groundwater in (NSAS- FD), emphasizing the prediction of the permissible yield and the lowest groundwater levels. The results of calibration indicate that the hydraulic conductivity of the aquifer ranges between 5.75 and 9.25 m/d. Calibrated specific yield ranges from 0.00001 to 0.0001. The results of scenarios showed that the predicted drawdown ranged from 7.0 m to 9.0 m after simulation period (50 years). A major decline of groundwater levels will be more in near future period, sequentially, the faster for natural balance of aquifer system during 13 years. It is highly recommended that the reclamation activities in the southeastern part of the study area are the proper location.