Groundwater Flow Modeling in a Nubian Sandstone Aquifer, South Western Desert, Egypt

This paper presents a methodology for management and evaluation of groundwater aquifer in the Middle Part of Darb El-Arbaein Area. Three dimensional lithologic modeling techniques have been used for detailed characterization and groundwater flow modeling of the aquifer system in the middle part of Darb El-Arbaein area. Well log data was used for setting the lithologic model using Rock Works software V. 15. A groundwater flow model, facilitated by MODFLOW 2011, was built using results of the lithologic model. The model is used for simulation of the groundwater heads and quality changes for next 10, 25 or 50 years under four different scenarios as follows :- (i) The first scenario with the present extraction rate which is 97360 m3/day to irrigate 2430 feddans, (ii) The second scenario is to increase the new cultivated lands in the studied area, the rate of groundwater extraction is 133360 m3/day to irrigate 3240 feddans, (iii) The third scenario is to change the discharge and working hours of productive wells, groundwater extraction rate reaches 48600 m3/day to irrigate 2430 feddans, (iv) The fourth scenario is to use the third scenario and increase new cultivated lands, the total rate of groundwater extraction is 64800 m3/day to irrigate 3240 feddans. The simulation results for the first and the second scenarios show that, the groundwater table started to decline due to the over pumping from the productive wells but the third and the fourth scenarios control and safe groundwater extraction. The non-reactive transport model MT3DMS has been applied along the flow model. It was found that TDS of the groundwater in the studied area increased throughout 10 years, but after 25 years there would not be a significant change of expected groundwater salinity and it became constant.