Changes of groundwater conditions on Jeju volcanic island, Korea: implications for sustainable agriculture

Abstract

Groundwater is the sole source of fresh water in the volcanic Jeju Island due to the absence of any perennial streams. Groundwater exploitation has been extensive and intensive for agricultural, domestic consumption, including drinking, and industrial purposes. In addition, ground source heat pumps (GSHPs; open, closed and underground air types) are now gaining popularity. The conservation of groundwater quantity and quality is therefore crucial to the sustainable development of the island. Groundwater use has continuously increased over the last decade (1999 to 2008) from 110 to 195 M m3/year, in line with the increasing number of groundwater wells, despite the introduction of many efforts for groundwater protection such as the banning of illegal groundwater well installation and the instigation of artificial groundwater recharge using harvested rainwater. Analysis of the long-term groundwater monitoring data showed a substantial waterlevel decline and corresponding electrical conductivity (EC) rise, which indicated enhanced seawater intrusion and groundwater quality deterioration. In this paper, the current status of groundwater conditions on the island is examined and some implications for its sustainable use are drawn. Key words: Groundwater, artificial groundwater recharge, ground source heat pumps, seawater intrusion, Jeju volcanic island.