Integrated Groundwater Modeling for Simulation of Saltwater Intrusion in the Nile Delta Aquifer, Egypt

Abstract

Groundwater in the Nile Delta aquifer is considered one of the most important water resources of Egypt. In the last 30 years, the abstraction rates from groundwater wells in the Nile Delta increased dramatically. The Nile Delta region is considered very vulnerable to the sea level rise in the Mediterranean Sea due to climate change. The main objective of this study is to build an integrated 3D groundwater model of the Nile Delta aquifer to simulate the saltwater intrusion under different climate change scenarios using the MODFLOW and SEAWAT programs with the actual irrigation canal network in the Nile Delta region. Also, it proposed different scenarios for management and control of saltwater intrusion in the Nile Delta aquifer. Google Earth Pro software was used to estimate the bank levels and top width of the irrigation canals within the Nile Delta region. The spatial and temporal variation of groundwater recharge from rainfall in the Nile Delta aquifer was estimated by using WetSpass hydrological model. ENVI software was used to come up with land use classification based on available land cover images of the Nile Delta for 1972, 1984, 1990, 2000, and 2009. The WetSpass model was calibrated by comparing the simulated groundwater recharge with the calculated one by using the water balance equation method. The results indicated close agreement in groundwater recharge between the two methods’ outputs. The WetSpass model was then applied in respect of 1970, 1980, 1990, and 2010 for the purpose of validation. The SEAWAT program was used to build an integrated groundwater model for the Nile Delta aquifer to simulate the saltwater intrusion where three scenarios are proposed: sea level rise, decreasing the south groundwater head due to additional groundwater pumping and combination of the two scenarios previously mentioned. The third scenario (combination between sea level rise and decreasing the groundwater head due to additional pumping) is the worst scenario. Finally, seven scenarios based on the built model results were proposed through decreasing the pumping discharges for management and control of saltwater intrusion in the Nile Delta aquifer. Reduction of the pumping discharges from all areas of the Nile Delta has a significant impact more than regional reduction and redistribution of pumping discharges in order to control the saltwater intrusion.