[enviro-vlc] UNESCO publishes first world map of underground transboundary aquifers
vern.weitzel at gmail.com
Thu Oct 23 13:17:19 EST 2008
UNESCO publishes first world map of underground transboundary aquifers
UNESCO is publishing the first-ever world map of shared aquifers to coincide
with the submission to the General Assembly of the United Nations on 27 October
of a draft Convention on Transboundary Aquifers. Almost 96% of the planet’s
freshwater resources are to be found in underground aquifers, most of which
straddle national boundaries.
Despite its strategic importance, no global inventory of this resource had been
compiled to date. Since 2000, UNESCO’s International Hydrological Programme
(IHP) has been participating in the establishment of a groundwater database. It
is now presenting a detailed map of transboundary aquifers – available online –
showing the delineations of aquifers that are shared by at least two countries.
It also provides information about the quality of their water and rate of
replenishment. So far, the inventory comprises 273 shared aquifers: 68 are on
the American continent, 38 in Africa, 65 in eastern Europe, 90 in western Europe
and 12 in Asia.
The aquifers, which contain 100 times the volume of fresh water that is to be
found on the Earth’s surface, already supply a sizeable proportion of our needs.
The growth in the demand for water since the second half of the 20th century has
been met by the increased use of underground resources. Globally, 65% of this
utilization is devoted to irrigation, 25% to the supply of drinking water and
10% to industry.
Underground aquifers account for more than 70% of the water used in the European
Union, and are often one of the only – if not the only – source of supply in
arid and semi-arid zones (100% in Saudi Arabia and Malta, 95% in Tunisia and 75%
in Morocco). Irrigation systems in many countries depend very largely on
groundwater resources (90% in the Libyan Arab Jamahiriya, 89% in India, 84% in
South Africa and 80% in Spain).
Although aquifer systems exist in all continents, not all of them are renewable.
For example, those in north Africa and the Arabian peninsula were formed more
than 10,000 years ago when the climate was more humid and are no longer
replenished. In some regions, even if the aquifers are renewable – being fed on
a regular basis by rainfall – they are in some cases endangered by
over-exploitation or pollution. In the small islands and coastal zones of the
Mediterranean, populations often use groundwater more rapidly than it is
The aquifers in Africa, however, which are some of the biggest in the world, are
still largely under-exploited. They have considerable potential, provided that
their resources are managed on a sustainable basis. Since they generally extend
across several State boundaries, their exploitation presupposes agreed
management mechanisms in order, for example, to prevent pollution or
over-exploitation by particular States.
Mechanisms of this kind have begun to emerge in recent years. For example, in
the 1990s Chad, Egypt, the Libyan Arab Jamahiriya and Sudan established a joint
authority to manage the Nubian aquifer system in a concerted manner. In their
project concerning the Iullemeden aquifer, Niger, Nigeria and Mali approved in
principle a consultative mechanism for administering the aquifer system. But
such mechanisms are the exception.
The draft Convention on transboundary aquifers, prepared by the United Nations
International Law Commission with the assistance of experts from UNESCO’s
International Hydrological Programme (IHP), is therefore intended to fill a gap
in the law. The text to be submitted to the General Assembly of the United
Nations on 27 October, calls on aquifer States not to harm existing aquifers, to
cooperate and to prevent and control their pollution.
The World-wide Hydrological Mapping and Assessment Programme (WHYMAP) was
launched in 1999* to improve knowledge and management of the Earth’s resources,
particularly groundwater. In 2000 the IHP launched the Internationally Shared
Aquifer Resources Management (ISARM) project to compile an inventory and to
evaluate the world’s transboundary aquifer systems (delineating them, estimating
their volume, their replenishment rates, etc.). A region-by-region evaluation
has been launched. In its initial phase it will identify geographical locations
and then itemize the legal systems of each country as they relate to aquifer
* By UNESCO with the assistance of the Commission for the Geological Map of the
World (CGMW), the International Association of Hydrogeologists (IAH), the
International Atomic Energy Agency (IAEA) and the German Federal Institute for
Geosciences and Natural Resources (BGR).
Author(s):Press Release N°2008-108
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