Adaptation through Water Storage
The Role of Water Storage
in Adaptation to Climate
Change in the HKH Region
Ramesh Ananda Vaidya, Integrated Water and Hazard Management, ICIMOD, rvaidya@icimod.org
I
ncreasing water scarcity is a serious threat arising reduced volume of snow and ice, and the changes in
from climate change in Asia in general, and the precipitation, could lead to a serious shortage of water
Hindu Kush-Himalayan (HKH) region in particular. for drinking and farming. When the consequences of
The level of water withdrawal (demand) in Pakistan climate change are superimposed on the high degree
for example is already about three-quarters the level of intra-annual rainfall variability in the region, marked
of annual renewable water resources available by too much water in the wet season followed by too
(supply); whereby a demand greater than one-third little water in the dry season, it is clear that the threat
of supply is already considered risky. In 2005, the of water scarcity could pose a serious challenge to
annual water availability per person in Pakistan the approximately 1.3 billion people living in the ten
was below the critical stress level of 1700 cubic river basins that have their origins in the Hindu Kush-
metres (cum) per person per year to meet irrigation, Himalayan mountains. For example, India has a skewed
industrial, and household water demand, and judging pattern of rainfall distribution, receiving 50% of its annual
from the rate at which it declined between 2000 rainfall in just 15 days. According to Biswas (2004)
and 2005, it may soon fall below the minimum need Cherrapunji, with the highest rainfall in India receives its
of 1000 cum per person. The water availability annual rainfall of 10,820 mm between June and August
is quickly approaching the critical stress level in in about 120 hours, but faces a water shortage problem
Afghanistan, China, and India as well. during the dry months. A critical issue, then, is how
to store massive quantities of rain falling in very short
Most rivers in the region are shared between several
periods so that it can be used over the entire year.
countries, making water resources and their management
a matter of regional concern. Both Bangladesh and Furthermore, there is a relationship between the intra-
Pakistan receive more than three-quarters of their surface annual rainfall variability in a country and its level of
water supply from across their borders. And during the prosperity. Countries with low rainfall variability typically
dry season in the densely populated and fertile Ganges have high GDPs (gross domestic products), while
Basin of India, almost three-quarters of the surface water countries struggling with large seasonal variability in
fl ows from Nepal. water availability typically have low GDPs (Brown and
Lall 2006). Increasing the capacity to store water and
Climate change is projected to have severe adverse
reduce seasonal differences in availability may help to
effects on water availability in the region with overall
redress this balance. The current water storage capacity
changes in precipitation patterns The total amount may
for countries in the Hindu Kush-Himalayan region is much
increase in some areas and be less in others, leading
below the estimated needs for food security. Estimates
to water stress and droughts. More precipitation may
of seasonal storage requirements are based on the food
fall as rain instead of snow, reducing both long and
requirements of the population, the area of cultivated
short-term storage. Precipitation may also increase in
land, and the rainfall distribution pattern over the year.
intensity with more falling over a shorter time resulting
According to estimates, only 33% of the seasonal
in a higher incidence and intensity of fl oods in the river
storage requirement is met in Bangladesh, while 76%
basins and a higher proportion of runoff and reduction
is met in India (Table 1). This implies the need to view
in groundwater recharge, again reducing storage. A
development of water storage capacity as an integral
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