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 m 3 /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.

Carbon and Nutrient Inputs by Litterfall in Evergreen and Deciduous Forests in Korea

“…The Gotjawal has been the most interesting research site in Korea due to its unique biogeographic feature, characterized by its unique forest ecosystem structures formed on widely and disorderly distributed lava blocks [23]. Jeju is the largest volcanic island in South Korea where temperate and subtropical species coexist [24,25]. Jeju Gotjawal is also home to more than 1990 taxa of vascular plants, of which 90 taxa are endemic to Jeju such as Quercus glauca Thunb., Euphorbia octoradiata H.Lév.&Vaniot ex H.Lév, and Codonopsis minima Nakai [26].…”

Effects of land-use types and the exotic species, Hypochaeris radicata, on plant diversity in human-transformed landscapes of the biosphere reserve, Jeju Island, Korea

“…Therefore, soil nutrients on the island are easily leached by run-off, leading to low soil fertility ( Harcombe, 1980 ). Groundwater in Jeju Island is the sole source of fresh water because of the absence of perennial streams and is used extensively for cropland irrigation ( Choi and Lee, 2012 ). Increased irrigation results in higher soil salinity of croplands than other land-use types because increases in irrigation inevitably lead to increases in soil salinity ( Oosterbaan, 1997 ).…”

Silicon Fractionation of Soluble Silicon in Volcanic Ash Soils That May Affect Groundwater Silicon Content on Jeju Island, Korea

“…Dissolved Si (DSi) in the soil solution is absorbed by plants, and leached Si is moved from the river to the sea. Jeju Island has no permeant stream or river due to the high permeability of its volcanic ash soils and lava and pyroclastic flows [10,11]. Hence, much of the precipitation permeates the soil and enters groundwater, which makes it easy to leach DSi into groundwater.…”