Water has always been and will continue to be
crucial to the development of deserts. But opinions
about water development have changed. Fifty
years ago there was immense faith in engineers
and in state investment to support them (in
the western, socialist, oil-rich, and Third World
countries alike). But this faith closed planners'
ears to warnings about the long-term impacts and
real costs of water projects (Reisner 1986). Today,
this legacy considerably constrains opportunities
in three ways. First, the need to clean up the
consequences, as discussed; second, the need
to extricate policy from the past and to construct
better policy for the future; and third, the depleted
and degraded state of whatever water remains.
Building more dams and drilling for more
groundwater still tempt the policy-maker, and in
many cases the temptation is undeniable. The
ongoing debate in Pakistan about a proposal for
a dam at Kalabagh on the Indus system illustrates
the problems of this course. The water in the
Indus and its tributaries is already thoroughly
utilized; demand for water is rising with population
and modest increases in prosperity; thus the
distribution of water is increasingly controversial.
The huge dams that were built with foreign aid
after the signing of the Indus Waters Treaty in
1960, as at Tarbela (on the Indus itself) and Mangla
(on the Jhelum), are filling with sediment (Tate
and Farquharson 2000). The first dams took the
best sites, leaving sites that are less than optimal.
Large, impounded reservoirs lose large amounts of
water by evaporation. Dam-building requires huge
investment, with questionable long-term returns,
and no guarantee that the water they save will
not lead, as the water from earlier dams did, to
salinization. Climate change will probably decrease
the flow of the snow- and ice-fed rivers that are
Pakistan's main sources of water.
A high proportion of desert river water is already
used. The Colorado River in the USA, the Nile and
the Mesopotamian rivers are now nearly completely
utilized. Siltation of reservoirs happens worldwide;
in the next few decades, sediment may clog the
outlets of the Glen Canyon dam (inaugurated only
in 1963) on the Colorado River in the U.S.; some
NGOs are already calling for its decommissioning.
Almost all the sediment in the Colorado and the
Nile is retained; the figure is 60-80 per cent in the
Tigris-Euphrates system (Vörösmarty and others
2003). The time between the completion of large
dams and the point where siltation threatens to
close them is running at about 30 to 40 years. If
so, many more will soon be threatened.
Returns on investment from water schemes are
debatable. In the Central Valley of California, state
subsidies on water, in one case, and at one time,
amounted to about $217 per acre per year, for
land that yielded crops with a value of only $290.
The crop was cotton, a highly water-consumptive
crop, in national surplus and grown more cheaply
in other parts of the USA, let alone elsewhere in
the world (Reisner 1986). Of course, dams yield
more than water, particularly hydroelectric power
and recreation, and these must always feature
in cost-benefit analyses, but all of these benefits
are threatened by siltation, an almost inevitable consequence of dam-building. There are many other
examples in which the underpricing of water, or the
non-collection of fees for water (for whatever reason)
has encouraged profligate use, which in turn may
accelerate salinization and waterlogging (Ray and
Williams 1999). Many of these stories would have
applied to Australian water management in the past,
but there has now been radical reform aimed at the
more effective and less environmentally-damaging
use of water (Turral and others 2005).
Groundwater, with some exceptions (Box 5.2),
also has problems. Saudi Arabia's trajectory on
groundwater illustrates some of these. The city of Riyadh is close to a large supply of groundwater,
yet the government chose to sell this water cheaply
for agriculture (to promote food security), and to
supply the people of Riyadh with desalinated water
pumped up from the ROPME Sea Area, at much
greater cost. As in the history of desert water
development in the USA, the cheapness of the
water allowed Saudi farmers to grow highly waterconsumptive
crops and even livestock (Figure 5.6;
Water supply can be improved only by combining
technology and management. Some technologies
(Box 5.3) may make a great impact locally (as for
new hotels or isolated settlements), and could play
a greater part in this role. Some are only feasible
at large expense and high consumption of energy.
A small number, like the desalinisation of brackish
water, are both cheap and widely applicable.
Better policy will depend on learning the lessons
of the many twentieth-century water policies that squandered rather than conserved water. Given the
escalating water crisis in many deserts, caused not
least by the old policies, better policy is urgent.