Environmental Engineering Reference
In-Depth Information
year, which is in sharp contrast with the 1 billion m
3
of water withdrawn annually from
domestic water sources (Haddadin, 2003; Hoekstra and Chapagain, 2007, 2008). People
in Jordan thus survive owing to the fact that their 'water footprint' has largely been exter-
nalized to other parts of the world, for example the USA. Intelligent trade largely covers
up Jordan's water shortage: export of goods and services that require little water and
import of products that need a lot of water. The good side of Jordan's trade balance is
that it preserves the scarce domestic water resources; the downside is that the people are
heavily water dependent.
For countries that depend on the import of water-intensive products, it is important to
know whether the water thus saved has higher marginal bene
ts than the additional cost
involved in importing these products. Let us consider the example of Egypt, a country
with a very low rainfall - the mean rainfall is only 18 mm/yr - and with most of its agri-
culture being irrigated. The import of wheat in Egypt implies a saving of their domestic
water resources of 3.6 billion m
3
/yr, which is about 7 percent of the total volume of water
Egypt is entitled to according to the 1959 agreement on the use of the Nile. The national
saving is made with the investment of foreign exchange of US$593 million/yr (ITC, 2004),
so that the cost of the virtual water is US$0.16/m
3
at most. In fact, the cost will be much
lower, because the costs of the imported wheat cover not only the cost of water, but also
the costs of other input factors such as land, fertilizer and labor. In Egypt, fertile land is
also a major scarce resource. The import of wheat not only releases the pressure on the
disputed Nile water, but also reduces pressure to increase the area of land under agricul-
ture. Greenaway et al. (1994) and Wichelns (2001) have shown that in the international
context Egypt has a comparative disadvantage in the production of wheat, so that the
import of wheat into Egypt implies not only a physical water saving, but also an economic
saving.
fi
Export of water-intensive commodities raises national water demand
Water is not merely a local resource to meet local demands for water-based products. In
the period 1997-2001, 16 percent of world water use was not for producing products for
domestic consumption but for making products for export (Hoekstra and Chapagain,
2007; 2008). The nations with the largest net annual water use for producing export prod-
ucts were the USA (92 billion m
3
), Australia (57 billion m
3
), Argentina (47 billion m
3
),
Canada (43 billion m
3
), Brazil (36 billion m
3
) and Thailand (26 billion m
3
). The main
products behind the national water use for export from the USA were oil-bearing crops
and cereal crops. These products are grown partly rain-fed and partly irrigated. In
Australia and Canada, the water use for export was mainly related to the production of
cereals and livestock products. In Argentina and Brazil, water use for export was primar-
ily for producing oil-bearing crops. The national water use for export in Thailand was
mainly the result of export of rice. Much of the rice cultivation in Thailand is done during
the rainy season, but irrigation is widespread, to achieve two harvests per year. In the
period 1997-2001, Thailand used 27.8 billion m
3
/yr of water (sum of rainwater and irri-
gation water) to produce rice for export, mostly grown in the central and northern regions
(Maclean et al., 2002). The monetary equivalent of the rice export was US$1556
million/yr (ITC, 2004). Hence Thailand generated a foreign exchange of US$0.06/m
3
.
Recall that currently 16 percent of the water use in the world is not for producing prod-
ucts for domestic consumption but for making products for export and let us simply
