Freshwater supplies threatened in centr...( Madison WI JULY 9 2007 An internati...)

Madison, WI, JULY 9, 2007 An international team from The Australian National University, Ecowise Environmental, the Government of the Republic of Kiribati, the French agency CIRAD and the Pacific Islands Applied Geoscience Commission has been studying the impacts of natural and human-induced changes on groundwater in the central Pacific nation of Kiribati since 1996.

The work was initiated by UNESCO International Hydrological Programme and supported by the Australian Centre for International Agricultural Research, the Government of France, the Australian Academy of Science, the Australian Research Council and the European Union Pacific Water Governance Programme. Their work is published in a special issue of the Aug. 2007 Vadose Zone Journal which followed an International Symposium on Groundwater Resources Assessment under the Pressures of Humanity and Climate Change held in Kyoto in April 2006 and coordinated by the Japanese Research Institute for Humanity and Nature.

Very limited land areas and extremely permeable coral soils in atolls reduce surface runoff to insignificant amounts and decrease the potential for surface storages of water. This means thin lenses of fresh groundwater floating over seawater are the major source of reliable freshwater for people in many atolls. The team found that both the quantity and salinity of atoll groundwater is extremely vulnerable to frequent ENSO-related droughts. Droughts can last as long as 4 years and occur with a frequency of one significant drought, coupled to La Nia events, every 6-7 years. In long droughts domestic water wells are often too salty too drink and some communities have to rely on large groundwater lenses or on coconuts.

Population growth due to natural increases, inward migration and urbanization mean that fresh groundwater sources are reaching their limit of sustainable supply in urban South Tarawa in Kiribati. Groundwater can become salty due to over-pumping or inappropr
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