Atlas of hidden water may avert future conflict
What the UNESCO map reveals is just how many aquifers cross international borders. So far, the organisation has identified 273 trans-boundary aquifers: 68 in the Americas, 38 in Africa, 155 in Eastern and Western Europe and 12 in Asia.
Each trans-boundary aquifer holds the potential for international conflict – if two countries share an aquifer, pumping in one country will affect its neighbour's water supply.
http://aquadoc.typepad.com/waterwired/2008/10/unesco-publishes-global-shared-aquifer-map.html