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Go BackWELL FACTSHEET - Regional Annex South AsiaRainwater Harvesting in South Asia Author: Suma Mathews and S. Sreekumar, SEUF, December 2005 Quality Assurance: Jo Smet and Kristof Bostoen In Hindu
mythology water is considered as sustainer and
purifier. In ancient days water was treated with
reverence, with mechanisms to preserve and judicial
consumption being practised in most parts of India.
The early Hindu texts written around 800-600 B.C.
reveal some knowledge of hydrological relationships
(the philosophical reflections of Vedas and
Upanishads). Evidence of water supply for domestic
use and irrigation with water harvesting systems can
be found in Kautilya’s Arthasatra written in 3rd
century B.C. Records show that people knew about
rainfall regimes, soil types and irrigation
techniques, dams, canals, tanks and embankments.
They developed a range of techniques to harvest
every possible form of water. These included
technology for spring water systems with split
bamboo pipes, catchments basins and traditional
water harvesting tanks such as tankas and kundis.
Traditional techniques varied from state to state
and even region to region because of diverse
patterns of monsoon and terrains of the country. In
the hills and areas with high rainfall, rooftop
collection and storage by constructing
dug-cum-embankment types of structure were used. In
the foothills, the flow of springs and streams were
arrested and stored. And in the desserts surface
rainwater collection was preferred. From those early
days effective systems of water management had been
established and operated by small communities in
many regions of the country. India
is blessed with good quality rainwater, average 1220
mm/year or about 400 million-hectare meters
(= 4,000 billion m3) of rain annually over a
geographical area of 3,290,000 km2. If rainwater is properly conserved it can be
used to fulfil all water needs in the country. Nowadays,
85% of the drinking water in India originates from
surface and groundwater. However, massive
exploitation of groundwater has led to lowering of
water tables and depletion of aquifers. In 1996,
there were 65,000 villages in India without water
sources. Changes in life style increase water
demands, and consumption, population growth etc.
make effective rainwater harvesting a necessity. See
also the WELL Global Domestic Rainwater Harvesting
Fact Sheet: http://www.lboro.ac.uk/well/resources/fact-sheets/fact-sheets-htm/drh.htm Frequent droughts in Southern Africa are threatening availability of food and food security in the region. Much of the response by governments of the countries in this region have tended to be on developing water resources mainly through construction of dams and irrigation schemes. This option often involves water transfer from one catchment to another, which besides being expensive to implement and to maintain, has a negative effect on the environment. One answer to the current crisis might lie in the promotion of rainwater harvesting techniques, especially as a source of water for domestic use and for agriculture between dry spells. Kerala,
the most southern state in India, has 44 rivers, 29
fresh water lakes and perennial springs and the
highest well density in the world (250 open
wells/km2). Despite the fact that most of these
sources of water are used for piped water supply
schemes, Kerala is facing acute water scarcity in
summer months. The density of population in this
state is very high. In many coastal areas saltwater
intrusion renders the groundwater brackish and
therefore unsuitable for drinking. Although Kerala
gets an average rainfall of 3,000mm/year, most
during monsoon, and because of geographical
conditions, most runs off to the sea within a short
time. The improper management of storm water causes
floods and droughts every year in the country.
Harvesting and conserving this rainwater for
domestic and small-scale irrigation use is the most
promising practice to solve these problems.
Rainwater harvesting is particularly important in
arid and semi arid regions, in remote isolated
habitations in difficult terrains, and where
chemical contamination makes existing water sources
unfit for domestic water use. Thousands
of Indian villages still do not have a local potable
water source within one kilometre or groundwater
within 15 meters. These villages are treated as
problem villages. In many parts of India water
quality is very poor due to chemical and
bacteriological contamination, presence of germs
etc. Reservations against Rainwater People
in many parts of the world are reluctant to use
rainwater as drinking water for a variety of
reasons. For instance traditionally in Kerala people
believe that only well water is good for drinking
because it tastes good. They also believe that water
in wells should get sunlight. Stored water is not
pure water, and hence people in Kerala prefer open
contaminated wells. Rainwater harvesting is not
viewed as a modern technique. Furthermore, rats (may
cause leptospirosis) and droppings of birds on the
roof may raise fear and doubts on the water quality. Therefore,
awareness raising of the advantages of rainwater
harvesting is needed to create demand and to
motivate people to get them involved in the whole
process. Rainwater harvesting can be most successful
in areas facing water problems due to scarcity and
contamination. Rainwater Harvesting in Kerala The
collection and storage of rainwater can be in
man-made structures or natural depressions.
Catchment areas can be rooftops, compounds, rocky
surfaces or hill tops. Rooftop harvesting structures
on islands like Lakshadeep and in the North Eastern
Provinces are very successful. The
most popular means of collecting rainwater for
individual households is from the roof tops. Another
method of harvesting rainwater is collection of
runoff rainwater in abandoned dug wells, recharge
pits and recharge trenches. These methods are for
groundwater recharge, which eventually helps in
raising the water table. For instance in Chellanum
Grama Panchayat in Kerala roof water is harvested
around the dug wells to recharge the well and reduce
the salinity intrusion. Rainwater
can be collected from large roof surface areas to
underground sumps. From the sumps water can be
pumped to overhead tanks. After proper water
treatment this drinking water can be supplied to
institutions. Rainwater from clusters of households
can also be collected in large storage tanks and
after suitable treatment the drinking water can be
distributed. The
Kerala government is implementing such projects in
Varsha Scheme. Varsha is a project of Kerala Water
Authority to construct rainwater harvesting
structures for low income families. The
beneficiaries contribute 10% and the government 90%
of the total cost. This project is implemented by
experienced agencies. The
Union Ministry for Urban Development in India has
asked the State Governments to take legislative
steps to ensure maximum possible collection of
rainwater. Many State Governments have already taken
steps in this direction, such as Tamil Nadu,
Karnataka and Kerala. The
Local Self Government institutions are asked to
adhere to rainwater harvesting rules while issuing
building permits.
Special rules are issued to construct
rainwater harvesting structures in houses,
building complexes, schools and government
buildings depending on the plinth area of the
buildings. The
Government declared 2004 as the “Year for
Rainwater Harvesting”.
With the objective of promoting rainwater
harvesting, the Kerala Government has set up a Rain
Centre under the nodal agency- Kerala Rural Water
Supply and Sanitation Agency. They are functioning
as resource centre, coordinating the Government and
non-government agencies (NGOs) as well as conducting
information and education campaigns. Rain
Centres have been established in Chennai , Meerut
and Trissur by the initiative of NGOs to demonstrate
different working models and to provide assistance
to the public for designing rainwater harvesting,
locating masons, materials etc. Only
the 10,000 litres rainwater harvesting tank designs
have been approved by the Government Departments.
Larger tanks are commonly constructed but no
standard designs have been approved. The relationship between health and water quality should be imparted to the community through water literacy campaigns. Health and hygiene promotion should be an integral part since behavioural changes associated with water use, proper maintenance of systems and sustainability of facilities and behaviour change are the key issues. In short, “water should be everybody's business!"
This
Region Specific Annex has been prepared by Suma
Mathews and S Sreekumar from the Socio-Economic Unit
Foundation (SEUF), Kerala, India
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