Evaluation of hydrogeological characteristics in Jeju Island, Korea

Jeju Island is a volcanic one composed predominantly of permeable basalts. The water resources of the island are dependent almost entirely on groundwater. It is essential to fully understand the hydrogeological conditions of the aquifer systems for proper and sustainable development of groundwater resources. Groundwater characteristics, including water levels and aquifer parameters in the island were evaluated using extensively collected hydrogeologic data. Groundwater levels on the island were located in a range between -26 and 282 m above sea level. Groundwater levels in the northern and southern basins are generally higher than those in the eastern and western basins. Fluctuation patterns of groundwater levels and ECs were classified into three types: sinusoidal fluctuations of both water level and EC, sinusoidal fluctuation of water level only, and no distinct fluctuation pattern. Generally, there were higher groundwater yields in coastal areas than inland areas. The groundwater was most productive in the trachybasalts and basal groundwater areas. This paper is providing a summary of several investigations on the hydrogeological characteristics of the aquifers in the island.