Environmental Engineering Reference
In-Depth Information
Losses of as much as $16 billion have been
reported for the 1980 drought in the US Great
Plains (Karl and Quayle 1981), and a figure of
$2.5 billion has been estimated for the 1984
drought on the Canadian prairies (Sweeney
1985). Amounts such as these would seem to
support investment in irrigation equipment, but
such direct economic considerations may not
always satisfy environmental concerns. If the
investment is made, there may be a tendency to
introduce irrigation into areas not particularly
suited to arable agriculture, rather than have
equipment lying idle. This may create no
problems in the short term, but, during the longer
periods of drought common on the plains, these
areas would be the first to suffer. If no investment
is made, in times of drought there may be an
attempt to offset the lower yields by bringing
more land under cultivation. Whatever the
decision, the net result is that additional land
Figure 3.12
The causes and development of desertification
