Sustainable Mountain Development No. 56, ICIMOD, Winter 2009
Table 1: The gap between storage capacity and storage needs ponds and tanks, as well as small and large reservoirs
(see Figure 1). In addition, there are constructed systems
Country Seasonal Storage Current storage,
Index as a percentage
designed to augment existing natural storage, like
(cubic km) of Seasonal groundwater recharge systems, bunds, and temporary
Storage Index
runoff collection areas. A comprehensive ecosystem
Bangladesh 62.28 33
framework is needed to explore the potential and
Bhutan 0.40 0
opportunities at the river basin level holistically. Different
India 356.60 76
types of natural and artifi cial storage systems are
Nepal 29.86 0
discussed in the following.
Note: The Seasonal Storage Index indicates the volume of storage
needed to satisfy annual water demand based on the average
Ice and snow
seasonal rainfall cycle. The study identifi ed 23 of 163 countries
studied as having a positive storage requirement, ie a need to
The greater Himalayan region has the largest bodies of
reduce the impact of rainfall variability on food and livelihoods by ice outside the polar caps with a total area of more than
transferring water availability from wet months to dry months. China
100,000 sq.km. From a storage point of view, these
and Pakistan were not among the 23; Afghanistan and Myanmar
may not have been studied. Source: Brown and Lall (2006)
glaciers, ice-fi elds, and snow packs provide important
intra- and inter-annual water storage facilities.Snow
part of integrated water resources management (IWRM);
can store water for anything from hours to years, but
this is also considered by the IPCC to be an adaptive
perhaps most important is its storage on a multi-monthly
measure for climate change impacts. To this end,
basis, thereby retaining water from the wet to the dry
countries in the Hindu Kush-Himalayan (HKH) region
part of the year. Glaciers are also crucial. A glacier is
with high rainfall variability need to think seriously about
a complex physical feature in which water as a liquid
developing water storage capacity for adaptation to
can be stored on, in, under, and adjacent to the ice.
climate change. Some of the potential water storage
Water can be stored in a glacier as snow, fi rn (perennial
options for adaptation to climate change and rainfall
snow), and ice, thereby delaying the release of water
variability are discussed in the following sections.
from the glacier by anything from hours, to days, weeks,
months, years, decades, or even centuries (see Figure 2).
Potential water storage options for climate
change adaptation
Thus, both snow packs and glaciers provide important
water storage facilities in the greater Himalayan region.
To understand the potential of water storage for climate
However, the contribution of meltwater from snow and
change adaptation in the Himalayan region, it is
ice to the rivers of the greater Himalayas still needs
necessary to look at the natural storage systems in the
to be understood much better. In general, the relative
cryosphere and the biosphere, as well as examining
contribution is larger in the west, for example in the Indus
constructed systems. The natural systems in the
and Amu Darya basins, while in the east where large
cryosphere include snow, ice, and the glacial lakes. The
parts of the meltwater coincide with abundant runoff
natural systems in the biosphere include soil moisture,
derived from monsoon precipitation, meltwater contributes
groundwater aquifers, and natural water bodies and
a relatively smaller proportion (Eriksson et al. 2009).
wetlands. The constructed systems include artifi cial
Figure 1: Water storage options (Source: adapted from IWMI 2009)
Figure 2: Schematic graph showing different forms of glacier storage
and their corresponding time-scales
SUBSURFACE SURFACE ACCESS
(Source: adapted from Jansson, Hock, and Schneider 2003)
Short-term Intermediate-term Long-term
Reservoirs
Dam outlets, pumps
storage storage storage
off-take towers
small large
Direct, buckets, Ice Glacier volume
Ponds and tanks
pumps
Snow
Seasonal snow cover
Aquifers
Boreholes, deep/
shallow wells, etc
deep shallow
Water in fi rn
Water
and management complexity
Soil moisture Planting crops
En- and subglacial water
increasing capital, environmental and social costs
Singular event storage (dammed lakes, jökulhlaups, surges, etc.)
Natural wetlands All of the above
increasing storage reliability increasing storage reliability Hour Day Month Year Century
11
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