Evaluation of the potential impact of Grand Ethiopian Renaissance Dam and pumping scenarios on groundwater level in the Nile Delta aquifer

The main objective of this study is to evaluate the potential impact of Grand Ethiopian Renaissance Dam (GERD) and pumping scenarios on groundwater level by a three-dimensional groundwater model of the Nile Delta using MODFLOW software. The Nile Delta has highly intensive irrigation canals networks that share yearly about 35.5 km 3 of water. In this study, an integrated three-dimensional groundwater model is built considering the actual condition of the irrigation canals and their recharges of the Nile Delta aquifer. The model was calibrated for estimating the vertical and hydraulic conductivity. The model was run for three scenarios: (1) reduction of water depth in canals, (2) increasing pumping discharge from the aquifer and (3) combination between the first and second scenarios. Results reveal that the effect of increasing the pumping discharge on groundwater level in the Nile Delta is more significant than decreasing in the water depth of canals network due to the fact that the existence of the upper clay layer which reduce the permits of water to penetrate and reach the groundwater in the aquifer. The last scenario presents the worst case as the average drawdown reached 1.26 m, 1.7 m and 1.35 m in western, central and eastern parts of the Nile Delta respectively. The study results should be taken in account for studying the saltwater intrusion and climate change impacts on the Nile Delta region.