Sustaining water, easing scarcity - Population Action International

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.
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