Sea level rise due to climate change increases the risk of seawater intrusion through coastal aquifers in Korea. In the view point of topographic characteristics, the slope of the west coast is gentle, while the slope of the east coast is very steep. Therefore, as the groundwater level gradient decreases away from the coastline, the interface between seawater and freshwater expands, which causes seawater intrusion. In this study, the impact of sea level rise on seawater intrusion through coastal aquifers was evaluated spatiotemporally using seawater intrusion monitoring network (SIMN). The results showed that the groundwater level change of the aquifer on the east coast is relatively more affected by groundwater recharge than by sea level rise, and that the recharge effect is more persistent than in the past. On the other hand, the annual variation of groundwater level on the west coast decreases as it moves away from the coastline, indicating that sea level rise has a significant impact on the aquifer. After comprehensively reviewing these results with the groundwater quality analysis and the survey results of representative watersheds, it is determined that the aquifer on the west coast of Korea is more vulnerable to seawater intrusion than on the east coast.

Keywords: Sea level rise, Seawater intrusion, Coastal aquifer, Groundwater level, Groundwater quality