Modelling Climate Change Impact on Seawater Intrusion using Density-Dependent Flow model

As the supply of freshwater for several coastal towns worldwide, as well as for agricultural and industrial uses, coastal aquifers are crucial to the sustainability of communities. However, because of rising sea levels and altered rainfall patterns, climate change has a significant effect on these aquifers. The issue is made worse by anthropogenic effect from excessive pumping. When combined, they can result in substantial seawater intrusion, which has an impact on coastal towns and users and presents difficulties for sustainable development. A limited number of studies have been done on the hydrogeological and environmental conditions in Saudi Arabia's Eastern Province, especially on seawater intrusion and climate change impact. Mitigating the effects of climate change requires an understanding of the relationship between seawater intrusion and climate change. this study fills this knowledge gap by examining the long-term impacts of climate change on seawater intrusion in the area. A density-dependent transport model was developed using SEAWAT to simulate seawater intrusion under three scenarios. These scenarios accounted for projected sea level rises of 0.58 m, 0.70 m, and 0.91 m, respectively, with recharge rates ranging from 4.5 to 5.89 mm/year. Simulation time extends until the year 2100. The results indicated a substantial inland shift of the freshwater-saltwater interface, with the horizontal extent of saltwater encroachment increasing over time.The study shows that the major contributor of seawater intrusion effects results from sea level rise, and the effect of changing precipitation in minimal and could be considered negligible. Based on the results of this study, it is recommended to follow adaptive water management strategy to deal with this problem. Some measures such as lowering groundwater extraction and combining it with injection wells can have a good impact on the seawater intrusion issue. Results show that these measures demonstrated effectiveness in mitigating the impact, reducing the affected saline area in the aquifer, and reversing the saltwater-freshwater interface.