Traditional Water Harvesting
wonders of water managment in dry areas. The karez Lessons for the future
system consists of a series of wells starting from the
The different techniques described above are just a few
foothills along the hill slope and linked at the bottom
of the different systems developed by farmers living in
by an underground channel that collects and brings
varied climatic, topographic, and geological conditions.
groundwater to the bottom of the hill. The water
Many of these structures may be able to help meet the
can be taken out vertically or drawn at the mouth of
growing water demand of an ever-increasing population
the channel at the foot of the hill. Wells are used to
if they are maintained and promoted. Not every
reach the channel for periodic maintenance and to
system can be replicated; hiti, for example, cannot be
remove the deposited sediment using buckets. The
built anymore as the engineering is unclear. But these
unique advantage of this system is that it helps access
traditional techniques offer a core message: that only a
groundwater for irrigation using gravity and minimises
combination of disciplines including culture, tradition,
evaporation loss in channels that are usually tens of
climate, and forest, land, and water engineering can
kilometres long.
help manage water sustainably; and that surface ‘blue
Hiti or dhunge dhara water’ sources cannot be sustained if ‘green water’ is
The hiti (or dhunge dhara) system is a unique water
degraded.
harvesting system developed in the 6th century AD to
In order to understand this core message, we need
provide domestic water to the urban residents of the
to realise that the traditional water planners relied on
Kathmandu Valley. A hiti is a stone spout that channels
watershed functions by which rainwater is distributed,
water from springs or a shallow aquifer usually about 10
as surface runoff, soil moisture, and groundwater
metres below the surface of the ground. Most hiti were
reserves, unlike the modern water planners, who with
built in a lined pit about 3 to 10 metres deep, while some
sophisticated tools and structures are able to transfer
were built at the bottom of slopes where there were natural
water from any source and are often inclined to view
springs. Shallow aquifers deplete fast, so canals called
streams as neverending sources. They understood that
rajkulo were built later to recharge the aquifers. The rajkulo
precipitation is asymmetric and available only for a
brought stream water from hills tens of kilometres away. In
few months of the year, and that only a small portion is
addition, ponds were built close to the hiti to augment the
stored naturally.
aquifer by storing rainwater (Shakya 1993). The hiti system
is an excellent example of how a prudently designed system
It is important to understand that for all practical
using a combination of structures and methods can help
purposes surface or ‘blue water’ means visible stream
manage even a shallow aquifer to provide a sustainable
fl ow. Most modern techniques for managing water
water supply. Many of the centuries-old hitis continue to
are related to blue water sources, replenished by
supply water in Kathmandu today, but there are hundreds of
groundwater in the upland areas, which in turn is
others that have become dry due to urban encroachment.
recharged only when the soil above is saturated. The
sustainability of blue water sources depends on what
Other techniques
fraction of rainwater has gone into the groundwater.
Water harvesting is not limited to the above examples. This is where managing rainwater in upland areas
There are many other types of systems used elsewhere in becomes important for maintaining both green and
the world. Most of them tap runoff water from micro- blue water sources. The traditional water harvesting
catchments rather than rainwater. Farmers in southern systems carry a wealth of wisdom. Analysing them can
Tunisia, for example, use a system called jessour, in help us understand the limitations of the area-specifi c
which a series of cross walls are made across small water cycle and its components and help us identify
streams called wadi that originate from a mountain sustainable ways to manage water.
catchment. Sediment deposited behind the walls is used
to grow fi gures and olives or other crops after the water
References
drains out. Farmers in West Asia and North Africa use
Agarwal, A; Narain, S (1997) Dying Wisdom. Rise, Fall and
earthen reservoirs called tanks and hafaer to store water
Potential of India’s Traditional Water Harvesting Systems. New
in gently sloping areas that receive runoff water from a
Delhi: Centre for Science and Environment
stream originating from large catchments. Similar tanks
Shakya B, (1993) (BS 2050) Swanigalaya Lonh Hiti (Stone
are also used in southern India. Tanks can store tens of
Spouts of Kathmandu Valley). Kathmandu: Lok Sahitya Parishad
thousands of cubic metres of water, which is used for
irrigation, while hafaer store only few thousand cubic
Upadhya, M (2009) Ponds and landslides, water culture, food
systems and the political economy of soil conservation in mid-
metres and are primarily for domestic uses.
hill Nepal. Kathmandu: Nepal Water Conservation Foundation
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