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World aquifer map unveiled

Written By Gopal Krishna on Monday, October 27, 2008 | 3:48 AM

UNESCO publishes 1st world map of underground transboundary aquifers

UNESCO is publishing the first-ever world map of shared a quifers to coincide
with the submission to the UN General Assembly on 27 October of a draft
Convention on Transboundary Aquifers, according to a press statement from the
world body here. An aquifer is an underground layer of water-bearing permeable
rock or unconsolid ated materials (gravel, sand, silt, or clay) which provides
colored pictures and information on why water is important and how it's
frequently used.

Almost 96% of the planet's freshwater resources are to be found in underground a
quifers, 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 man's
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 Libya, 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 replenished.

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, Libya 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
Interna t ional Hydrological Programme (IHP), is therefore intended to fill a
gap in the law.

The text to be submitted to the UN General Assembly 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.

22/10/2008
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