Lee, H.-J., Maeng, S.-J., Kim, D.-H. and Lee, S.-O., 2024. Effect on irrigation water usages due to seawater intrusion under typhoon season in Korea. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 720-726. Charlotte (North Carolina), ISSN 0749-0208.

In coastal areas near estuaries, the phenomenon of seawater intrusion into inland regions occurs due to the coastal aquifers containing salinity. Among these, agricultural wells, installed for the purpose of utilizing irrigation water, are affected as the intrusion of saltwater limits the usability of the water. Particularly, the fluctuation of saltwater influx caused by event-based occurrences such as typhoons and tides can accelerate the penetration of saltwater into these wells. To prevent the salinized damage, it is essential to figure out the impact of coastal conditions on the supply of irrigation water. Because of the limitations of visual survey for investigating groundwater salt intrusion, analytical solutions and numerical models have been used widely. This study was aimed to analyze the effects of variations in coastal conditions on saltwater intrusion and its impact on irrigation water supply using finite element method based OpenGeoSys. The Geumgang estuary barrage in South Korea was selected as the study area, reflecting the storm surge from typhoon BOLAVEN in 2012 and temporal tide level was considered through curve input. The feasibility of using irrigation water was evaluated based on the permissible salinity concentration of 0.6 psu for agricultural water suggested by Food and Agriculture Organization (2016). It is anticipated that the future incorporation of atmospheric boundary conditions and the accumulation of well usage data could significantly aid in the estimation of available water resources and inform policy decisions on the irrigation water usages.