Geography Reference
In-Depth Information
Figure 12.1
Cross-section
and plan of a
qanat.
countries with more than one third of their
cultivated area under irrigation are counted, the
number only increases to thirty-three.
of both developed and developing countries. No
better example is seen than in the USA. In the
early 1900s, the federal government committed
itself to a policy of opening up the west through
the development of irrigated agriculture by the
Bureau of Reclamation.
The work of the Bureau of Reclamation has to
be seen in terms of the overall pattern of irrigation
growth in the USA (see Box 12.1). Data from the
USA register a steady growth in the area of
irrigated land from less than 1.62 million hectares
in 1890 to a maximum of 20.2 million hectares in
IRRIGATION AS A DEVELOPMENT
TOOL
In the modern world, the political aspects of
irrigation development must not be forgotten, as
national governments have often used irrigation
as a tool in their policy options. This has been true
