H51K-1538
Long-term prediction of groundwater recharge by climate changes in the Gosan agricultural area, Jeju Island of South Korea

Friday, 18 December 2015
Poster Hall (Moscone South)
Eun Hee Koh, Dugin Kaown and Kang Kun Lee, Seoul National University, Seoul, South Korea
Abstract:
<span">Evaluation of long-term changes in groundwater recharge due to the climate changes is needed to secure the sustainable use of grounwater. In Jeju Island, which is composed of various formations of porous volcanic rocks, groundwater is a sole resource for water supply because of its hydrogeological characteristics. Therefore, preservation of the groundwater resource is an essential issue in the island. Prior to establishing a management plan for maintaining the groundwater resources in Jeju Island, long-term estimation of influencing factors are necessary. The Gosan study <span">a<span">rea is located in the western part of the island, where extensive agricultural activity has been performed and groundwater is a main source of supply for watering crops. In this study, we estimated the recharge changes for 100 years (2000~2099) in the Gosan agricultural area based on two climate change scenarios (RCP 4.5 and RCP 8.5) by using the HELP3 (Hydrologic Evaluation of Landfill Performance) program. The estimated component of water budget in this study are as follows (averaged in 2000~2014), precipitation: 1.28x108 m3/yr; ET: 6.49x107 m3/yr; runoff: 5.84x106 m3/yr; and recharge: 5.27x107 m3/yr. Over the 100 years of the estimated period, precipitation will have a highest increase among other meteorological parameters to be 6.16x109 m3 (RCP4.5) and 6.34 x109 m3 (RCP8.5). Increase in recharge by RCP8.5 scenario (2.75 x109 m3) will be less than that by RCP4.5 (2.77x109 m3) because ET by RCP 8.5 (ET: 3.34x109 m3; runoff: 2.27x108 m3) is estimated to be higher than ET by RCP4.5 (ET: 3.15x109 m3; runoff: 2.35x108 m3). Jeju volcanic island is known to have higher recharge proportions to the precipitation due to the distributed highly porous volcanic rocks. Therefore, variations in precipitation by climate changes would greatly affect the groundwater resource of the island.

Acknowledgement: This work was supported by the research project of "Advanced Technology for Groundwater Development and Application in Riversides (Geowater+)" in "Water Resources Management Program (code 11 Technology Innovation C05)" of the MOLIT and the KAIA in Korea.