Prediction of climate change and land use change impact on groundwater flow system in Jeju Island, South Korea

In this study, we applied an integrated model for predicting climate change and land use change impact on groundwater flow system of Jeju volcanic island, South Korea. In this study, a fully-distributed daily hydrologic feedback model (VELAS) was integrated with a 3D groundwater flow model (MODFLOW) to simulate the impact of vegetation, land cover, soil water dynamics and climate change on groundwater flow system. To address the land use change impact on groundwater flow, the long-term trend of land cover change was firstly investigated based on the earlier land cover maps and multi-layer perceptron (MLP). The projected land use pattern was then validated by comparing the actual land use map and modeled result. The climate change scenario of the study area was obtained using the different Representative Concentration Pathway (RCP) scenarios. The predicted model showed that with increasing temperature and precipitation, the long-term trend of groundwater recharge amount showed increasing trend. However, with more occurrence of extreme climate events such as droughts and extreme rainfalls, the model also projected the increasing spatio-temporal variability in various hydrological components (runoff, recharge, evapotranspiration). The projected groundwater level trend showed large difference between upland and lowland region- the groundwater level in lowland zone of the island would not experience notable change in the future, whereas the upland zone would suffer from significant decrease in groundwater level. The varying relationship between various environmental-, anthropogenic factors and hydrological responses was analyzed to provide a basis for improved integrated water resource management of Jeju Island.

Acknowledgement: This study was supported by the Korea Environment Industry and Technology Institute (KEITI) through the Demand Responsive Water Supply Service Program (#146526), funded by the Korean Ministry of the Environment (MOE) and Basic Research Project (#22-3411) of Korea Institute of Geoscience and Mineral Resources (KIGAM).