Forwarded to the Portal by: Anuradha 
The United Nations Educational, Scientific and Cultural Organization (UNESCO) will publish the first-ever world map of underground aquifers, which account for some 96 per cent of global freshwater resources, the agency announced in a press release today. Despite their strategic importance, no global inventory of aquifers , most of which straddle international boundaries , had been compiled before UNESCO started work on its online map, which will be launched to coincide with the submission to the General Assembly of a draft Convention on Transboundary Aquifers next week. The UNESCO is presenting a detailed map identifying underground water resources that are shared by at least two countries, using data compiled since 2000 by UNESCO's International Hydrological Programme for a groundwater database. The map will include information about the quality of water and rate of replenishment of the 273 transboundary aquifers , 68 in the American continent, 38 in Africa, 65 in Eastern Europe, 90 in Western Europe and 12 in Asia. Underground aquifers account for 70 per cent of water used in the European Union, and are often the only source of supply in arid and semi-arid areas , 100 per cent in Saudi Arabia and Malta, 95 per cent in Tunisia and 75 per cent in Morocco. Irrigation systems also depend largely on groundwater resources in many countries , 90 per cent in Libya, 89 per cent in India, 84 per cent in South Africa and 80 per cent in Spain. Aquifers, which contain 100 times the volume of freshwater than that on the Earth's surface, in Africa are still largely under exploited. They are among the largest in the world and since they generally expand over several national boundaries, their exploitation presupposes an agreed management mechanism. Mechanisms of this kind have begun to emerge, such as the agreement in the 1990s between Chad, Egypt, Libya and Sudan which established a joint authority to manage the Nubian aquifer system, but such arrangements are the exception, according to the UNESCO release. The draft Convention presented to the General Assembly on 27 October is intended to facilitate the creation of such mechanisms for administering transboundary aquifer systems by calling on aquifer states not to harm existing aquifers, to cooperate, and to prevent and control their pollution.
Read the more on the UNESCO page here: UNESCO publishes first world map of underground transboundary aquifers