Geography Reference
In-Depth Information
Figure 12.3 Irrigated area
and water use in the USA.
Figure 12.4 Water use in Israel.
establishment of settlements, many of which are
based on irrigated agriculture, in the occupied
parts of theWest Bank.
UNSUSTAINABLE IRRIGATION—
EXCESSIVE RIVER ABSTRACTION
AND THE MINING OF GROUNDWATER
The pace of technological change in the twentieth
century has meant that human societies now
possess the ability to utilise water resources for
irrigation and other purposes at a rate in excess of
the natural regeneration of water supplies. Perhaps
the most spectacular example of the depletion of
surface water resources is found within the
watershed of the Aral Sea in Central Asia
(Levintanus 1992; Precoda 1991).This is a basin of
inland drainage ringed by high mountains to the
south and south-west. In these mountains of the
Tien Shan and Pamir are found the headwaters of
the two main rivers—the Amu Dar'ya and the Syr
Dar'ya. Precipitation here is between 800 and
1600 mm each year, but downstream on the plains
around the Aral Sea precipitation falls to less than
100 mm per annum. In the period since the
Second World War, and especially since the 1960s,
there has been massive irrigation development on
these plains using waters from the Amu Dar'ya and
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