Vulnerability assessment of groundwater recharge under extreme climate change in coastal area watershed of South Korea

Abstract

In recent times, climate change leads to the occurrence of extreme weather phenomena such as heavy rainfall, severe drought, heatwaves, and cold spells. From the perspective of the watershed hydrologic cycle, these changes have resulted in adverse effects, including an increase in surface runoff, evapotranspiration, and a decrease in groundwater recharge. Coastal areas, in particular, have a greater reliance on groundwater compared to inland watershed, making water resources vulnerable to climate change. Therefore, in this study, the Soil and Water Assessment Tool (SWAT) was implemented for the An-Seong-cheon watershed (1,627 km2), which is adjacent to the coastal region in South Korea. The SWAT was calibrated and validated for runoff and evapotranspiration. The estimation of groundwater recharge was conducted based on the calibrated water balance components, the average recharge was calculated to be 21.2% for the study area. Subsequently, extreme climate change scenarios were selected, by examining the Shared Socioeconomic Pathway (SSP) scenarios derived from the Intergovernmental Panel on Climate Change's Assessment Report 6 (AR6). The extreme climate change scenarios will be applied to the SWAT model to project future changes in groundwater recharge. Ultimately, the purpose of study is to evaluate the climate change vulnerability of groundwater recharge based on land cover characteristics within the coastal watershed. Key words: Coastal area, Climate Change, Groundwater recharge, Vulnerability Assessment, SWAT Acknowledge Research for this paper was carried out under the KICT Research Program (project no.20230166-001, Development of coastal groundwater management solution) funded by the Ministry of Science and ICT.