Estimation of Water Availability in the Korean Peninsula Considering Climate Change

Abstract

Climate change is projected to have a direct impact on the water resources. In case of the Korean Peninsula, more than a half of the total rainfall amount is concentrated in summer. It has been always important issues that spatio-temporal variability of an available water resources in the Korean Peninsula. The water availability is projected to be influenced by climate change and it is expected to more intensify. Variations in water availability is related with the land use which is directly affected by water resources, such as agricultural area, urban area, and forests. Therefore, the changes in spatial variability along with the temporal changes of water availability should be investigated to establish an effective management plan and draw an implication for future spatial planning. Available water resources can be defined in various ways, such as a storage of reservoir, and river discharge which can be used in a basin. This study defined water availability as a river discharge based on literature reviews. This study estimates water availability based on river discharge in the Korean Peninsula including North Korea, as the study area. In order to estimate water availability and draw a spatial implication considering climate change, HadGEM2-AO and RCP 8.5 scenario is applied as a future climate scenario, and grid-based hydrological model H08 is used. H08 was originally developed as a global hydrological model for the simulation of water availability in a spatial resolution of 1° 1°. However, it is also applicable for a regional hydrological simulation in a spatial resolution of 5ˊ 5ˊ. Input meteorological data of GSWP2 is used for historical simulation, and RCP 8.5 scenario from HadGEM2-AO was used for future climate change simulation. A bias in air temperature and precipitation of GCM was validated by comparing with observed meteorological data in Korea. Parameters of H08 was calibrated and validated for historical simulation of 10 years from 1986 to 1995, then climate change simulation is carried out for the estimation of hydrological changes using validated H08. In order to investigate hydrological characteristics and water availability in the Korean Peninsula, representative gauging stations was presented for Amnok, Duman, Chongchon, Taedong River basin in North Korea, and Han, Nakdong, Geum, Yeongsan River basin in South Korea. Quantitative hydrological characteristics were presented for the representative 8 stations in the Korean Peninsula along with the meteorological aspects. Spatio-temporal variability was investigated for the hydrological attributes, such as evapotranspiration, runoff, as well as air temperature and precipitation. Estimated water availability based on RCP 8.5 scenario was spatially presented for the objective periods in order to derive spatial implication for the planning. However, there is uncertainties for future projection in the process of selecting future climate scenarios and hydrological model. This study assumed naturalized discharge which is not considering regulated flow due to the reservoir operation and artificial water supply capacity. This study estimated water availability on a grid basis using regionalized global hydrological model. The results of this study can be used as preliminary information for establishing spatial planning under climatic changes across the Korean Peninsula considering water availability.