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Adaptation through Water Storage
Natural wetlands Soil moisture and constructed ponds
There are around 665 sq.km of wetlands within the Soil moisture plays a vital role as a natural system of
HKH region. The Ruoergai Marshes on the Qinghai- water storage. For soil moisture, the frequency and
Tibetan Plateau in southwest China, located at 3400- intensity of rainfall are at least as important as the total
3900 masl, are a good example of the role Himalayan amount of precipitation. Watershed management,
wetlands play in a natural system of water storage. The through improved land cover and water conservation
marshes soak up the snow and ice meltwaters of the practices, can help to maintain soil moisture and support
Himalayas, and release them steadily to the streams that rainwater harvesting. It could play a crucial role in
feed the Yangtze and Yellow rivers. This helps to regulate improving infi ltration so that groundwater percolation
fl ow and prevent the fl ash fl oods that could endanger can be increased to help aquifer recharge. This is often
the livelihoods of people living downstream. achieved by practising low tillage farming and mulching
in farmlands and by increasing humus on topsoil in
In recent times, many glacial lakes have formed in the
forests. Surface water runoff can, of course, be stored in
Himalayan region due to the retreat of valley glaciers.
built structures such as ponds and tanks.
According to ICIMOD’s inventory, there are 8790 glacial
lakes with a total area of around 800 sq.km, in Bhutan, As an example, it is interesting to note the indigenous
Nepal, and selected areas of China, India, and Pakistan. ‘zabo’ system of cultivation practised in Kikruma
These lakes may also have the potential to be used to village of Nagaland, which uses a holistic approach
increase water storage capacity, provided appropriate to watershed management. A catchment area at the
technology is available to mitigate GLOF (glacial lake top of a slope is kept under natural vegetation to serve
outburst fl ood) risks. We need to explore the range of as a water source during the monsoon (1); ponds with
mitigation measures that could be taken against potential earthen embankments are dug below the catchment
GLOFs along the lines of the initiatives in the Andes in area to harvest water for irrigation and livestock (2);
South America, to make such water harvesting safe. cattle yards fenced with ordinary branches or bamboo
are maintained below the ponds and the pond run-
Figure 3: The zabo system of water storage and management
off water used for cleaning the yards (3); fi nally, the
cleaning water, now enriched with manure, fl ows into
rice terraces at the lowest level of the slope (4) (Figure 3,
redrawn from Agarwal and Narain 1997).
(1)
Aquifers
Five ways have been identifi ed in which a portion of
the monsoon fl ows could be stored underground by
groundwater aquifer recharge in the Ganges Basin
through increasing infi ltration into the water table. These
are (i) water spreading in the piedmont deposit (Bhabar
zone) north of the Terai belt of springs and marshes;
(ii) constructing bunds at right angles to the fl ow lines
in uncultivated fi elds to slow down run-off and increase
infi ltration; (iii) pumping out the underground aquifers
during the dry season in the neighbourhood of nallahs
(2)
(natural drains) which carry water during the monsoon;
(iv) pumping out groundwater during the dry season
along certain tributaries of the Ganges to provide space
(3)
for groundwater storage; and (v) increasing seepage
from irrigation canals during the monsoon season by
extending the network of canals, distributaries, and
water courses for kharif (rainy season) irrigation and
pumping out this seepage water during the dry season
(Revelle and Laksminarayana 1975).
The unconsolidated Bhabar zone and the Terai plains
constitute a very large groundwater reservoir in the
(4)
Himalayan region. Every year in Nepal, 2800 million
12 (4)
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