Impact of Submarine Groundwater Discharge, Climate Change, and Land Use on Korea’s Coast

The impact of climate change on fresh submarine ground discharge (SGD) variation on the Korean Peninsula challenges coastal regions, making them susceptible to environmental degradation and economic impacts. This study provides the first regional estimates of fresh SGD along the entire coast of the Korean Peninsula from 1980 to 2016, utilizing established water balance methods. Our results indicate that the western and southern coasts of South Korea experience higher fresh SGD rates due to greater net precipitation compared to the North Korean region. The impact of drainage length is evident when examining the East and West coasts. Notably, substantial tidal flats on the West coast, where tidal differences significantly influence high SGD rates, are particularly significant. Climate change affects fresh SGD variation, with South Korea's western and southern coasts showing rising trends in spring and winter, while North Korean coastal watersheds display a consistent increase across all seasons. Our findings highlight the vulnerability of Korean coastal regions to climate change and land use development, affecting 15% of the coastline. Specifically, the increased development and agricultural land in South Korean coastal catchments have exacerbated vulnerability by 38% since 1990, driven by economic growth, population expansion, and shifts in cultivated crops.