Of
all the water on earth, 97.5% is the oceans, thus the total fresh water is only
2.5%. Pakistan is divided into three hydrological units: the Indus basin,
covering an area of over 566,000 km2 (70% of the surveyed area in the country),
the Kharan desert in west Balochistan with its inland drainage, and the arid
Makran coast along the Arabian Sea in the south. The total watershed area of
the Indus basin, or the region that drains into the river, as well as the river
system itself, is 944,000 km2, 60% of which lies in Pakistan.
The
effect of climate change on water resources is expected to be significant. An
analysis of changes in the hydrological regime can provide a basis for
estimating the impacts of climate change on water resources, and can be used as
a tool to recommend changes in the water management regimes. In general,
increase in temperature would not only increase water demand because of higher
evaporation rates, but may also increase rainfall due to additional moisture
supplied to the clouds because of higher evaporation from the sea surface.
Similarly, increased rainfall may cause increase in intensity of floods.
|