The
four-day International Conference on Water Resources of Arid and Semi-Arid
Regions of Africa (WRASRA) that was held in Gaborone, Botswana from 3-6
August 2004, ended with delegates from all over the world calling for a “new
international cooperation to use water resources to the best international
advantage”.
Conference
delegates noted that water scarcity was the underlying factor behind water
resource problems within a society or between nations. Water resource scarcity
“can lead to changes in access rights, changes in property rights, changes in
property relations, greater conflicts, livelihood changes, loss and disposal of
other assets, over-exploitation and competition for resources”.
Delegates
attending the conference also noted that scarcity of water “often leads to its
non-sustainable use”.
Over
60 papers addressing global water management issues were presented at the
conference.
Presenting
a key paper on the sustainable management of water in arid and semi-arid
environments, scientists from the Institute for Hydromechanics and Water
Resources Management at the Swiss Federal Institute of Technology in Zurich,
Switzerland said, “Globally, the most widely spread forms of non-sustainable
water use practices are over-pumping of aquifers, drying-up of wetlands and soil
salination on irrigated land.”
The
scientists said sustainable management of scarce water resources could only be
achieved in the long term, “through much more careful management of scarce
resources”.
Participants
to the conference said that modeling was a valuable tool in the analysis of
management options and scenarios. New types of data from remote sensing,
airborne geophysics, and environmental tracers are among the few modern methods
that “allow reaching a new quality” of prediction.
Freshwater
– A Scarce Resource
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Agriculture and natural
vegetation are fierce competitors for the available freshwater
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Freshwater
is a scarce resource on a worldwide basis. This becomes apparent by looking at
the global freshwater balance. Of the 110,000 km3/area of precipitation on the
landmass of the earth, 50,000 km3/area are returned to the atmosphere via
evapotranspiration by the planet’s natural plant cover. Another 21,000
km3/area are used by man-made ecosystems (18,000 km3/a by rain-fed agriculture
and 3,000 km3/a by irrigated agriculture). This shows that agriculture and
natural vegetation are already fierce competitors for the available freshwater.
Scientists
said that of the 13,000 km3/a accessible runoff, about 4,000 km3/a are used by
mankind and 70 percent of this goes into irrigated agriculture.
“This
means that a global water crisis would above all be a global crisis in food
production,” said the scientists from the Institute for Hydromechanics and
Water Resources Management at the Swiss Federal Institute of Technology.
“Compared to the 13,000 km3/a available [as accessible runoff], the abstracted
4,000 km3/a appear small. One should, however, not forget that these figures are
averaged in time and space and therefore hide the real problem; for example,
droughts and floods.”
The
scientists said that though most severe in arid regions, “water scarcity is on
a global level”.
Sustainable
Water Management
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Over-pumping of aquifers is
one of the non-sustainable practices of water use
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Scientists
and representatives from water management authorities attending the conference
said that sustainable water management “is a practice, which avoids
irreversible or quasi-irreversible damage to the resource water and other
natural resources linked to it, such as soil and ecosystems”.
Water
scarcity and poverty are often the causes of non-sustainable behavior as they
lead to overexploitation and depletion of stocks.
Global
Sustainability in the Water Sector
Delegates
attending the conference agreed that in order to identify big and possibly
existential problems for whole regions, “we have to look for ubiquitous
negative global trends”.
They
identified the following as some of the non-sustainable practices, which are of
global importance: over-pumping of aquifers, destruction of wetlands, salination
of soils, and the pollution of aquifers with persistent pollutants.
Globally,
about 800 km3/a of freshwater are abstracted from aquifers. About one quarter of
this abstraction is non-sustainable in the sense that it is not replaced by
recharge. On the Arabian Peninsula, in North Africa, China and the arid Western
United States for example, abstractions for large-scale irrigation have
withdrawn large quantities of fossil water, which under present climatic
conditions are no longer replenished.
Meanwhile,
the conference released information showing that the global area of wetlands has
diminished by 50 percent since the year 1900. This has a dramatic impact on
species diversity. It is a consequence of the competition between natural and
man-made ecosystems for land and water resources.
Millions
of People’s Lives Compromised
With
over 160 million people living and farming in arid and semi-arid areas of
Africa, delegates attending the conference warned that failure to manage water
sustainably would compromise on human and environmental well being.
The
delegates noted that while science could give some decisions in support of
sustainable water management, “the decisions for or against sustainability are
made in the political arena”.
Presenting
a paper on “Challenges for Managing Water Resources in Semi-Arid Areas”,
scientists from the University of Zimbabwe’s Department of Soil and
Agricultural Science, and Midlands State University’s Department of Soil
Science and Agriculture said, “Arid and semi-arid areas receive below 600mm of
annual rainfall and together with increasing population and lack of
infrastructure, this means that many people have inadequate access to water.
Water scarcity and irregularity in rainfall are increasing due to the effects of
EL Niño and possibly to the impacts of global warming.”
The
scientists said that the variability and unreliability of rainfall makes the
sustainable development of water resources difficult, hence the need to come up
with clear management strategies.
“Good
management of and secure rights to water resources are crucial to livelihoods
and particularly to people’s capacity to cope with variability,” said the
Zimbabwean scientists. “Water also provides a means for the diversification of
livelihoods. It is also important for addressing poverty and rural development
since it is used for food production.”
The
scientists noted that Sub-Saharan Africa was among the regions suffering from
water scarcity and that climate change “is likely to increase the water
stress”.
They
concluded, “There is now a need to investigate more thoroughly, the links
between water potential resource base and how it is managed during the season
and dry years and see if there are any opportunities for reducing water
scarcity.”
*
Emmanuel Koro is an environment and development communication specialist based
in Zimbabwe. He is also President of the Sub-Saharan Africa Forum for
Environment Communicators (SAFE), which aims to promote the conservation and
development views and interests of rural communities in the media. Your emails
to will be forwarded to him by contacting the editor at: ScienceTech@islam-online.net.
