Sustainable Mountain Development No. 56, ICIMOD, Winter 2009
Harvesting techniques catchments. Aahals are usually located close to a
village where runoff and, if possible, seepage can be
Ruza or zabo
collected. They are around 20 to 50 sq.m and less than
Rainwater harvesting systems are common in hill areas
two metres deep. A pokhari is around 3000 to
where water is scarce, despite heavy rainfall, as for
5000 sq.m; but the shape and size varies depending
example, in the hills of Nagaland in North East India
on the space available. A pokhari is made both to lower
where there is an acute shortage of drinking water.
the peak discharge in the runoff channel and to augment
Managing rainwater in Nagaland means combining a
soil moisture. Some pokhari are found strategically
typical landuse pattern with water collecting structures
located to hold potentially trouble-creating runoff, while
The upper part of the hill slope is kept forested, below
some are found in grassland or on rainfed farmland
this are terraces, and below them cattle yards. The base
(Upadhya 2009). In areas where the land is more
of the slope is used to cultivate paddy. Ponds, ‘ruza’,
porous, over-topping of the pond during high rainfall
can wash the sides away and cause the water to fl ow in
a gush. In such areas, farmers build several small ponds
rather than a few big ones. Similarly, more smaller
ponds are usually built in grazing areas as they keep a
larger area moist for a longer period of time for growing
grass. Large landholders also build private ponds in front
of their houses which they may use for fi sh farming.
Johad
A Johad is a commonly used water harvesting technique
in western Rajastan in India. It consists of a small but
long earthen bund (small checkdam) built on the upper
side of the land to hold back surface fl ow during rainfall
and allow every drop of rainwater to soak into the soil
and augment the groundwater. The system had fallen
into decay until a severe drought in the 1990s when
many were restored. Revival of thousands of such johads
in one district not only helped farmers to grow food but
or ‘zabo’, are built on the ridge tops, and the middle also raised the groundwater level by almost 6 metres,
terraces to collect runoff. The stored water is used for the bringing the once dead Arvari river back to life.
animals, and then runs down to the paddy fi elds.
Ahar pyne and pat
In Nepal, the monsoon rainwater is essential for the
Unlike Rajastan, southern Bihar receives a substantial
survival of the mountain communities, but is also the
amount of rain, but the area lacks water due to its gently
source of major problems. Erosion and landslides destroy
sloping land and sandy soil. The groundwater is deep.
lives and properties during the wet season, but there
People here use an ‘ahar pyne’ to collect fl ood water
is little water available in the dry season. The general
during the monsoon for later irrigation. The ahar is an
land use pattern in the Nepali hills is similar to that in
area enclosed on three sides with embankments and
Nagaland, but settlements are scattered at all levels and
connected to a swollen river via a pyne, a channel
cattle sheds and houses are usually found together. Nepali
which can be up to 20 kilometres long. The pyne
hill farmers have devised a systematic way of managing
passes through farmlands irrigating crops between the
runoff from the ridge to the valley with drainage channels
river and the ahar. The ahar beds are also used to
and ponds built at strategic points to hold, divert, and
grow winter crops after the water has been drained for
delay the fl ow of runoff. These techniques help to reduce
summer cultivation. Further south in Madhya Pradesh
rainwater-induced damage during the monsoon, while
a similar system is used to divert water from streams
building water reserves for the winter.
fl owing from the hills into irrigation channels called pats
via a stone diversion lined with leaves.
Aahal and pokhari
Karez
An aahal, or ‘place for wallowing buffalo’, is the Nepali
name for a type of shallow community pond built to The karez system is widely used in the arid areas of
collect runoff in the hills and mountains. A pokhari is western Pakistan, central Asia, and China where rainfall
larger than an aahal and collects runoff from small is very low. It is one of the traditional engineering
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