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Rain water harvesting
Save rain water…now!
Rain water harvesting can prevent water famine. Ground water
is meant for an emergency but we have been drawing it for our
daily use. The reckless use of ground water can deplete our
water resources dangerously. Storing rain water can prevent
such a calamity, says Mr. A. R. Shivakumar, Senior Fellow,
INEP: What is rain water harvesting? reverse the trend. If we do not redeposit what we have
Mr. Shivakumar: The source of water to wells, tanks and drawn from underground we will be in deep trouble.
rivers is rain water. Rain water conservation has been There are some very simple technologies that will enable
happening from thousands of years and there is nothing us to store and use rain water. This is known as rain
new in what we are doing now. As civilizations grow we water harvesting.
have more buildings, bigger villages and cities. When
such changes take place, the availability of water INEP: What is the need for storing rain water?
decreases. There is a need to conserve rain water apart Mr. Shivakumar: We are forced to conserve rain water
from having water in tanks, rivers and other places. There as there is a severe shortage of pure drinking water, be it
is a need to conserve water in our own homes. We have in cities or villages. Moreover, whatever little that is
a system called roof top rain water harvesting for this available is polluted. Therefore we have to depend on
purpose. The water collected on the terrace can be rain water. If we don’t do this now, then the bottled water
filtered, stored and used. which you buy for Rs.12 - Rs.15 per litre will be the water
that will be seen only in a museum! We have to really
We have a lot of rainfall in our country. In Karnataka there struggle for water. Before such a situation develops it is
is 1200 mm of rain a year. We cannot store all the water better we store rain water.
that falls on the ground, but whatever we can is a lot of
water. Rain water can be stored in tanks and sumps at INEP: What can be done to spread awareness about the
home. If there is more water we have to redeposit it in to need to store rain water?
the ground. For the last 30 - 40 years we have been Mr. Shivakumar: We were aware of the value of water
drawing ground water for our daily use. We have to all along. We were also self-sufficient in water resources.
108 PARISARA SOBAGU
The first thing a housewife did in the morning was to carry As the demand increases the use of water also increases.
a few copper vessels, clean them well with tamarind, As utilisation increases the demand also increases.
make it shine, and collect water and worship it. The water
was worshipped first and then the oven. All other activities We use to have a lot of space around wells or tanks.
would follow later. In other words water was treated like There used to be paddy fields, farms and gardens. In
the Goddess Ganga. They knew the value of water. They other words water had enough space to seep back into
could see divinity in water. Water was respected earlier. the earth. The water that would get into the earth would
Nowadays, we do not take water seriously. When we want get back into our wells and it was pure too. Now, tanks
it, we turn on the tap and use it and forget about it. and lakes are surrounded closely by buildings. Roads
are tarred. Pavements are covered with concrete slabs.
Another factor is that we seem to assume that water is There is absolutely no space for water to get
exclusively for human use. Even for a moment we do not underground. We have closed all channels.
think that the bio-diversity around us is also part of nature
and needs water. If you stand atop your building and look And whatever little water that was there underground we
around, you can’t see a single patch of open water. We have used it either through bore wells or wells. Now if
store water and lock it safely in sumps and tanks. We you don’t return the borrowed water to its original source
don’t let dogs, foxes or birds or sparrows or even insects there won’t be any water left underground. Water is like
to gain access to it. We have assumed that it is ours. money….if you keep withdrawing money from the bank
One of the reasons for such an attitude is that there is a and do not repay then one day there will be no money to
shortage of water. Less water is available now than in draw. Similarly, one day water will cease to come up.
earlier days. Earlier we used to have a tank or a well or
a lake around our house, from which we would draw INEP: So we will not have money when we really need it.
water. Now the demand for water has increased 100%.
Mr. Shivakumar: Underground water should be used
only in case of an emergency. But we have been using it
everyday— for 24 hours, 365 days— for our daily needs.
We shouldn’t do this. When it rains, the water that falls
on the terrace comes out through the pipes. That water
has to be stored in a bucket or a tank. This is sufficient
for all purposes for a day or two. This is a simple method.
If there is excess water that is collected in the drain or in
any other place, it can be channelled underground
through the help of a ‘sink pit’ or a dried up well. This in a
way is as good as replenishing the fixed deposit of water.
This will also help the future generations and in the
Storage of water and groundwater recharge
renewal of tanks.
PARISARA SOBAGU 109
INEP: There is this stored before our time, we will be in deep trouble.
notion that rain water can Mr. Shivakumar: There is a proverb that says if you sit
be stored only during the and eat, even a pot of money is not enough.
rainy season and that it is
not possible throughout INEP: For what purposes can the stored rain water be
the year. used?
Mr. Shivakumar: It Mr. Shivakumar: The stored rain water is pure water.
never rains throughout You cannot dream of better or purer water than rain water.
the year. In Bangalore we This can be used for all purposes. It can be used for
see a rainfall of 1000mm drinking. However, the terraces of our houses have dust,
per year. The rain fall is dry leaves, and droppings of birds and insects, which
Barrel method for recharging spread over 60-70 days. can pollute water. But if you filter this, you have pure
groundwater It does not rain drinking water. One can collect two to two and a half lakh
continuously for 60-70 litres of water on a 40ft x 60ft site at places where the
days but spread over a year. It is spread in such a way rain-fall is 1000 mm. But you cannot store all the water
that rain water is available all through the year off and that falls on the ground. Most of the water goes
on. If there is a big gap between two rainfalls, then we underground. The stored water can be used for all
cannot use rain water. We have to use the stored rain purposes like drinking, bathing, cleaning vessels,
water. We may have to use what has been deposited washing, mopping and watering trees and plants. In other
underground. Thus rain water is available throughout the words it can be used for various domestic and industrial
Rain water can be stored in tanks or sumps. When it is INEP: How much rain water can a person store?
exhausted, we can use ground water. We should use Mr. Shivakumar: It depends on how much water you
ground water only if we have returned the borrowed water. need. According to the World Health Organisation, a
Otherwise, we should not. The water has been stored person needs an average of 135 litres of water per day.
under the ground over a period of 100 or 1000 years. A family may need 500litres per day or 1.5 lakh to 1.8
We do not have the right to extract this water. If you want lakh litres a year. The stored rain water will be sufficient
10 litres of water then you have to give back 15 litres of for an entire family for a year. Sometimes you get more.
water to earth. Only then will you have the right to draw. So you don’t have to go in search of water. One can
Only then can our children and grandchildren see water, become self-sufficient.
otherwise we will have water famine.
Where do you think we get our water from? The water
INEP: If we want to use the legacy left behind by our that falls on our terrace reaches the drain, flows into a pit
forefathers we have to work hard, return about 20%, and or a tank or a river, from where it is pumped and sent
then use about 10%. If one ‘spends’ whatever that is back to the city through water pipes. Instead of this cycle
110 PARISARA SOBAGU
of water supply, a pipe. We need to have a filter at the end of the pipe,
we can store rain and this filtered water can be safely stored in a sump or
water and rely on a tank.
One can use a sand-bed filter or in some cases even a
INEP: What are cloth filter can be used. For channelling rain water
the other benefits underground a plastic barrel system designed by me can
of rain water be used. A plastic drum, cut off at the bottom, is placed
harvesting? at about two to five feet in the ground. Rain water gets
into these drums and reaches underground. In the same
way, a dysfunctional bore well or a bore well with
Pop up filter for filtering rainwater
insufficient water can be revived if rain water is allowed
Mr. Shivakumar: Rain water harvesting is one way of to enter it.
getting very high quality of water. People think that it is
the responsibility of the government to supply water. If INEP: How can stored rain water be used in industries?
you store rain water that falls on the terrace we can be Mr. Shivakumar: In our factories we use more water
self-sufficient and do not have to depend on anybody. than in our residence. It is also expensive because it is
Secondly, we get pure water. Thirdly, we get fewer not subsidised as in the case of water supplied to
diseases. We can also reduce soil erosion because water residences. Factories do not need pure water like drinking
that falls on the terrace or on the road is stored and not water. But they are using pure drinking water or Cauvery
allowed to flow away. The water that is supplied to river water. Instead, harvested rain water can be used
residences has to be pumped and purified. If rain water for industries. Factories already have a system to get rid
is stored, one can save on purification and electricity used of water collected on their terraces which are quite large.
for pumping. It can also help ground water level to The same system can be used to store rain water which
improve. So rain water harvesting offers us multiple can be used for recycling purposes. It can be used for
benefits. gardening. This way, industries can become self-sufficient
in water. They can save money on water which is
INEP: What are the methods adopted to store rain water? expensive. Thus they can increase their profit on their
Mr. Shivakumar: There are several methods. One is product.
storing rain water that falls on the terrace of individual
houses. When rain water falls on vacant sites, roads, INEP: How can stored rain water increase ground water
playgrounds, drains and paddy fields, the water can be level?
collected for community use. Thirdly, wells and tanks can Mr. Shivakumar: I said earlier that about 80% of the
be used to store rain water. These three can complete a rain water drains away. Around 20% of water seeps into
rain water chain. Having just one of the three is not the ground. This quantity is getting reduced because we
effective. have blocked the channels of water to get underground.
The rain water that falls on the terrace flows down through Now, we have started using artificial methods to recharge
PARISARA SOBAGU 111
ground water. This plastic barrel technology has to be INEP: Can you
used both in rural and urban areas. We have to recharge name some
our underground water so that water level in our wells places where
and bore wells will improve. It will stabilise for a while rain water
and then sink underground. So with very small and simple harvesting is a
techniques we can recharge ground water in an economic success?
manner. Mr. Shivakum-
ar: When our
INEP: Instead we use old and dried-up wells as dust bins organisation, the
for old clothes, tyres, plastic and other wastes. If we clean Karnataka State
and use dried-up wells for storing rain water it will Science &
replenish ground water. People say that there is nothing Technology Cor-
RWH at KSCST
new in rain water harvesting and that it has been practised poration, with
in some form or the other for several centuries. Comment. the help of the government of Norway began the rain
Mr. Shivakumar: That is very true. Some form of rain water harvesting programme in Bangalore, it adopted the
water saving or storing has been going on since the dawn methods that I have been using in my house as a model.
of civilization. Man always lived around water spots or
water bodies. He took steps to ensure water supply did I am using only rain water in my house. We used only
not dry up in summer. That was also a form of rain water stored rain water to build my home. I have not taken the
harvesting. Hundred-year old buildings in Rajasthan tell ‘water connection’ from the BWSSB or the Cauvery Water
us that this system was in practice centuries ago. One Scheme! Every drop of water used at my home for ten
can see a system of collecting whatever little rain that years has been the rain water harvesting method. We
fell on the terrace of those buildings in small tanks or are using that source for drinking too!
troughs. There was enough drinking water for a year or Our parent body, the National Institute of Advanced
two. Studies, has successfully adopted this method in the
Vidhana Soudha, the General Post Office, the Fire Station
A good thing about storing rain water is that it can be at Rajajinagar, the Kengeri Beedi Workers Housing
used for several months and even years, if it is filtered Colony and Kidwai Hospital and a few other major
and stored. But technology varied as towns and cities buildings in Bangalore.
developed. Earlier there was no need for much filtering.
Now it is necessary to do so. We have to ensure that Apart from this we have conducted hundreds of training
pipes do not have cracks. Some measures have to be workshops and awareness programmes all over the state.
taken while building tanks and sumps. Steps should be People have to accept that storing rain water is a
taken to ensure that sun rays do not fall on water. If they necessity. Along with the assistance of the Department
fall, water gets contaminated. It is necessary to learn of Panchayat Raj and Rural Development we have taken
about such small details. Then rain water harvesting up a programme to popularise this scheme in all districts
becomes very easy too. and taluks.
112 PARISARA SOBAGU
It has been made mandatory by the government to have The bamboo has to be split open and the nodes have to
rain water storing kit in all new buildings. be cleared for a smooth flow of water.
Student: Is it safe to drink stored rain water? Student: People use wood of areca nut trees as ‘gutters’
Mr. Shivakumar: Rain water is like nectar. It will not to store water….
harm us. But rain water fallen on the terrace, road and Mr. Shivakumar: That can be done too. If it is a flat roof
other such places is polluted with dust, droppings of terrace, the water that needs to be collected can be stored
insects, birds and animals. It has to be filtered before with the help of pipes. On open sites, people can filter
use. But if you can manage to drink rain water directly, it the rain water with the help of dhotis or saris whose four
is safe and does not harm you. ends are tied to pillars or branches of a tree.
This can be done at a height of three feet above the
The first rule of rain water harvesting is to avoid storing ground. The water stored after this process is clean
the water for ten minutes. Allow it to flow for ten minutes drinking water. Thus we can see that water can be stored
so that it washes the dust and other pollutants settled on in many ways.
the terrace. The water that is collected and stored
afterwards is clean and drinkable. If you are still Student: Where can we get more information regarding
apprehensive, then you filter the water with a well folded rain water storing?
dhotis or a cotton sari by placing it at the edge of the Mr. Shivakumar: People are becoming aware about rain
water pipe. The water you get then is fit for drinking. It water harvesting. Our institution, The Karnataka State
does not harm you. Science and Technology Corporation, is situated in
Bangalore. We provide information for all who want to
Student: Can rain water be used for agriculture? know more by fax or by e-mail or by telephone. Rain
Mr. Shivakumar: It is rain water that is used for agriculture water harvesting models are kept in all the zilla panchayat
all over India. The source of water for wells, bore wells, offices. All the ZP officers have been trained in this
tanks, lakes, reservoirs and rivers is rain water. The use method. Builders and contractors have been trained and
of rain water does not adversely affect agriculture. are familiar with this scheme. People can contact any of
them for more details. There are several organisations
Student: Can rain water be stored in all types of houses? that are familiar with this programme. In Bangalore there
Mr. Shivakumar: I can see that the moment the terms, is a Rainwater Harvesting Club. There is an organisation
‘Solar water heaters’ or ‘rain water harvesting’ are called ‘Caught’ at the National Institute of Engineering in
mentioned, people assume that these are not for them. Mysore. In Mangalore and Udupi regions people can
They presume that it is suitable for upper class people contact Sri Padre, a well known journalist. There are
with large open spaces on terraces. It does not matter several other organisations that can be contacted for
whether the terrace is big or small, sloping or flat. If the more details on rain water harvesting.
terrace has a slope, the water can be stored with the
help of a pipe or a ‘gutter’ made of bamboo or bronze.
PARISARA SOBAGU 113