The ImpEE Project: Improving Engineering Education

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Notes

Some water-stressed countries withdraw considerably more water than is renewed annually, leading to significant ‘water debt’.
The graph shows annual freshwater resources with countries arranged in descending order of water debt severity.1
Kuwait is currently the world’s most water scarce nation and also the worst water debt country, with an annual renewable freshwater supply of approximately 0.02km³/year and an annual freshwater withdrawal of around 0.54km³/year (2700% of available renewable supply). Saudi Arabia extracts the greatest volume of water (14.62 km³/year) beyond it’s renewable supply (2.4km³/year) and uses 7 times more than it has available, but UAE (1.91km³/year debt and consumption 10 times renewable supply) and Libya (4km³/year and nearly 8 times supply) are also bad water debtors.
However, even relatively water-rich countries can exceed their renewable supply; Uzbekistan has approximately 50.4km³/year renewable available freshwater, but withdraws around 58.05km³/year (115% of available supply). Uzbekistan has experienced the detrimental effects of this unsustainable over-use of freshwater and has witnessed the deterioration of the Aral Sea and its associated industry.
In comparison:
USA withdraws only around 20% of available renewable supply
UK withdraws only around 10% of available renewable supply
Canada withdraws only around 1.5% of available renewable supply
Brazil withdraws only around 0.5% of available renewable supply
Water-debt countries and regions meet their water withdrawals beyond the renewable supply in a number of ways, including drawing water across political boundaries, or depleting ‘fossil aquifers’ in some cases causing not only extraction of ancient groundwater reserves, but also causing irreparable collapse of the geological structure, thus preventing future recharge.
Energy-rich but water-poor countries, such as the water-stressed and water-debt oil-producing countries of the Middle East may use desalination techniques to produce freshwater from sea water.

Gleick, Peter (2003) “The World’s Water: The Biennial Report on Freshwater Resources” Island Press, (2002 Update)

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Water Debt Data