water Article Analytical Solution of Saltwater Intrusion in Costal Aquifers Considering Climate Changes and Different Boundary Conditions Ismail Abd-Elaty 1, Martina Zele ˇnáková 2,* , Katarína Krajníková 3 and Hany F. Abd-Elhamid 1,4 1 Department of Water and Water Structures Engineering, Faculty of Engineering, Zagazig University, Zagazig 44519, Egypt;
[email protected] (I.A.-E.);
[email protected] (H.F.A.-E.) 2 Department of Environmental Engineering, Faculty of Civil Engineering, Technical University of Košice, 042 00 Košice, Slovakia 3 Institute of Technology, Economics and Management in Construction, Faculty of Civil Engineering, Technical, University of Košice, 042 00 Košice, Slovakia;
[email protected] 4 Center for Research and Innovation in Construction, Faculty of Civil Engineering, Technical University of Košice, 042 00 Košice, Slovakia * Correspondence:
[email protected]; Tel.: +421-55-602-4270 Abstract: Groundwater contamination due to saltwater intrusion (SWI) has an extreme effect on freshwater quality. Analytical and numerical models could be used to investigate SWI. This study aims to develop an analytical solution to investigate SWI into coastal aquifers which was applied to a real case study at the Middle Nile Delta aquifer (MNDA). The study presented a new formula to predict the difference in depth of freshwater to seawater interface due to a change in boundary conditions. A Computer Program for Simulation of Three-Dimensional Variable-Density Ground- Water Flow and Transport (SEAWAT) is used for groundwater flow simulation and SWI and the Citation: Abd-Elaty, I.; results compared with the developed analytical solution. Four scenarios are considered in the study, Zeleˇnáková,M.; Krajníková, K.; including; the sea-level rise (SLR), reduction in recharge, over abstraction, and combination after Abd-Elhamid, H.F.