Besides implementing groundwater regulations, the Jeju government started an artificial recharge program (Jeju-friendly Artificial Recharge Technology) in 2007 to meet the growing freshwater demand (Kim et al., 2008). For this, 10 injection wells (50 m depth and 400 mm diameter) were installed at a middle elevation in a mountainous area. Rainwater harvested from the roofs of many greenhouses or stream water especially in the wet monsoon season (August to October), was injected into these wells (Lee et al., 2008). The provincial government plans to inject 15,000 m3 of rainwater per well. A second artificial recharge site is additionally under construction. As of 2009, 695,000 m3 of rainwater was being injected annually through 81 injection wells, including the clustered artificial recharge wells, which is equivalent to the annual water use of 5,600 people.