Sustaining Water, Easing Scarcity: A Second
Update
The Case of the Nile River Basin
Perhaps the most vivid example of the interaction of population growth, water
scarcity and international conflict is the vast basin of the Nile River in northeastern
Africa. The 10 countries with territory in the Nile basin contain 40 percent of Africa's
population (not all actually within the basin) and make up 10 percent of its land mass.
More than 85 percent of the Nile's water comes from the Blue Nile, which originates in
Ethiopia.24
However, the vast majority of the river's flow, estimated at about 85 billion cubic meters
annually, is used by Egypt, the last nation on the Nile's path to the Mediterranean Sea.25
For centuries the cultural symbol of Egypt, the Nile provides almost all the
fresh water used by more than 60 million Egyptians living along its banks. When few people
lived upstream-and modern economic development was a distant dream for the entire
basin-Egypt saw no reason to worry about its dependence on the Nile's waters. Its
complacency is now ending, however, as the upstream nations begin to harness the Nile's
waters to provide economic prosperity for their growing numbers.
Ethiopia, for example, recently emerged from a long period of civil war and
famine into a period of accelerated growth and economic development. The government has
overseen the construction of more than 200 small dams that will use nearly 500 million
cubic meters of the Nile's flow annually. Additional dams are being planned to increase
the country's irrigation and hydropower capacity.26
Though Ethiopia's current development plans will require only a small portion of the
Nile's water, its potential demands could significantly reduce the river's flow into
Egypt. Ethiopia has an estimated 3.7 million hectares of land, an area larger than
Belgium, that could be irrigated.27 With
a population nearly the size of Egypt's and a faster annual rate of population growth-3.2
percent annually for Ethiopia versus 2 percent for Egypt-Ethiopia will need to develop a
large portion of this land for agricultural use.28
Irrigating only half this land area with water from the Nile could reduce the river's flow
to Egypt by 15 percent.29
Hydrologists doubt the basin produces enough renewable fresh water to satisfy the
irrigation plans of both Ethiopia and Egypt.30
Egypt itself is raising the stakes with ambitious plans for its New Valley land
reclamation project. Pressed by population growth within its own borders, the Egyptian
government has begun a massive irrigation project in the country's western desert in an
attempt to persuade seven million Egyptians to move there from the crowded Nile Valley.
When completed, a pipeline will carry up to five billion cubic meters of Nile water from
the Lake Nasser reservoir to the New Valley site to facilitate the construction of new
cities and provide irrigation to more than 200,000 hectares of desert, an area more than
twice the size of New York City.31
Sudan, meanwhile, plans to build its own dam on the Nile north of the capital,
Karthoum, where the Blue Nile and the White Nile converge before flowing into Egypt.32 The
remaining Nile basin countries currently use only a small portion of the river's water.
However, with their cumulative population now numbering over 140 million and projected to
grow to more than 340 million by the year 2025, it is inevitable that these countries will
soon begin to lay claim to a larger share of the Nile's flow to meet their growing
irrigation and development needs.33
The Egyptian government has long recognized upstream development of the Nile's
waters as a potential national security threat and has stated its willingness to go to war
to preserve its access to fresh water. As the basin's governments come to understand the
dynamics of the population-water relationship, however, advance planning and diplomacy may
win out over saber rattling and armed conflict. In recent years, representatives of the 10
nations of the Nile watershed have met to review past agreements and consider possible
future ones related to their use of this shared natural resource.34
The whole world is watching the Nile and similar international watersheds. At a
March 1997 forum on international water issues in Marrakech, Morocco, UN Secretary General
Kofi Annan stressed that the projected growth of world population over the next 30 years
makes developing cooperative international agreements on shared water resources "one
of the most urgent issues on the global agenda."35 And
in May, the UN General Assembly approved a convention to establish guidelines for
cooperation on sharing the benefits of international watercourses.36 The
U.S. State Department and Environmental Protection Agency have opened field offices called
environmental hubs to help developing nations negotiate transboundary solutions to
regional environmental problems such as freshwater scarcity, deforestation and air
pollution, and to raise the profile of environmental issues in global diplomacy. The
Eastern Africa hub, which specializes in Nile Basin water resource issues, recently opened
in Addis Ababa.37
The growing interest in the region's water issues is encouraging, but the
challenge of reconciling competing claims on the Nile will continue to be complicated by
political and economic concerns. The scope for water conservation and international
cooperation is large, but the competition is unlikely to find permanent resolution until
the region's population approaches stabilization.
The Lessons of Water Scarcity Benchmarks
The benchmarks of water stress and water scarcity used in this report are not
intended to describe Malthusian limits to growth or strict natural thresholds governing
population-environment interactions with consistent and unalterable effects. Rather, they
serve as indicators of the likelihood of adverse consequences related to water shortage.
As such, these benchmarks can help predict the future urgency of problems related to
freshwater availability. Equally important, they can provide insight into how true natural
thresholds related to population-environment interactions might operate. In the real world
some countries with less than 1,000 cubic meters of renewable fresh water per person per
year manage to develop economically, while many countries with abundant water still
experience severe problems in supplying water to farms, factories and homes. Despite these
apparent inconsistencies, these benchmarks are recognized and used by many hydrologists
and by the World Bank and help illustrate important population-water relationships. To
understand different responses to water availability, it is important to explain a few of
the principles and limitations of the terms and analyses presented in this report.
First, the figures for per capita water availability presented here refer only
to renewable fresh water. This is defined as salt free water that is fully replaced in any
given year through rain and snow that falls on continents and islands and flows through
rivers and streams to the oceans. The figures do not include water that evaporates through
the heat of the sun or transpires through plants to the atmosphere, processes known
collectively as evapotranspiration. Excluding the amount of water lost to
evapotranspiration helps standardize the water availability figures for countries with dry
climates and those with wetter climates by counting only that amount of water that is
available for human uses-except to the extent that water availability varies by season.
Second, the water availability figures do not include supplies of groundwater
that are not replenished by precipitation on human time scales-also called nonrenewable or
fossil water. Many countries supplement their renewable water supplies by drawing down
their groundwater aquifers. Relying on nonrenewable supplies of groundwater is one way
that countries with less than 1,700 cubic meters of renewable fresh water per person per
year can avoid, at least temporarily, feeling the constraints of limited supplies of
renewable fresh water. However, for most countries this situation cannot be sustained for
long, especially as their populations continue to grow, their pumping costs begin to
escalate and their development requires greater quantities of water.
In addition, the water availability figures take no account of the timing or
seasonality of this availability. Fresh water is often more abundant in some seasons than
in others. Throughout the tropics, for example, rainy seasons often produce deluges of
renewable fresh water that cause damaging floods and can scarcely be captured for later
use. Months later the dry season sets in, drying rivers and streams to a trickle and
causing severe, though temporary, freshwater shortages. Under these circumstances, a
watershed or country that in theory has sufficient water for its inhabitants can face
shortages not accounted for by the annual availability of renewable fresh water. Much more
data on seasonal inventories of freshwater availability will be needed before the concept
of timing can play a significant role in analyses of population and water relationships.
As previously discussed, the ability of individuals and institutions to adapt to
different challenges can obviously vary widely among nations. For this reason, some can
naturally manage better than others as the per capita availability of renewable fresh
water declines. It would be inappropriate, therefore, to propose any precise levels as
absolute thresholds of water scarcity, or insist that they apply equally to all countries.
Instead we use the term benchmark to convey that these figures represent approximate
levels of freshwater availability-averaged over different climates, soil conditions and
economic development levels-below which concern about water shortage tends to rise
significantly. By applying these approximate benchmarks, we can establish a framework that
helps explain how population dynamics interact with finite resources such as renewable
fresh water.
Finally, the benchmarks described here are not meant to imply that countries
having more than 1,700 cubic meters of renewable fresh water available to each inhabitant
are automatically considered water abundant. This term proved to be misleading when used
in Sustaining Water: Population and the Future of Renewable Water Supplies because in many
countries-from India to Iran to the United States-the per capita water availability is
higher than the 1,700 cubic meter stress benchmark, yet the drier regions of these
countries experience significant water shortages at times. In addition, although countries
may appear to have a plentiful supply of renewable water, not all of these sources can be
exploited at an acceptable cost, given their location relative to population centers. Thus
the supply of economically available fresh water is often much lower than the estimates
provided here. In this update of Sustaining Water, the term relative water sufficiency
conveys the fact that countries with a per capita water availability in excess of the
stress and scarcity benchmarks are not guaranteed an abundant freshwater supply in all
times and in all places. Even the term "sufficiency" often overstates the
reality of freshwater availability in these countries-in the United States the examples of
southern California, the Florida Everglades and south Texas come to mind. Nonetheless, it
seems the most apt term to describe the condition of renewable water resources in
countries with a per capita renewable freshwater supply that exceeds the benchmark levels
for water stress or scarcity described in this update.
Next:
Table of Population and Annual Renewable Fresh Water Availability
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