Fundamentals of
Rain Water Harvesting
Vishal Bhanushali
Eureka Forbes Institute of Environment
May 06, 2009
Launched in 2000
Vision
Living an unpolluted life
is our children’s birthright.
Air Pollution
Ground Water Pollution
What is the need
for harvesting
rain water ?
Water in Urban Space …
Municipal water deficit
City
Mumbai
Delhi
Kolkata
Chennai
Banglore
Hyderabad
Need
Shortfall Shortfall %
4000
3830
2258
3000
840
956
1030
880
690
1050
135
186
25
30
30
35
16
19
Water in Urban Space …
Municipal water deficit
City
Indore
Bhopal
Lucknow
Jaipur
Jabalpur
Vaizag
Need Shortfall Shortfall %
318
335
560
349
239
305
134
70
120
313
94.5
146
42
21
21
89
40
48
RURAL INDIA IS SCREAMING FOR WATER!
‘Water now precedes roti, kapda, aur makan’
2/3rds of the country
has been declared
drought prone
90,000
villages
declared ‘no source
villages’- no source
within 7 km radius
Rajendra Singh, Tarun Bharat Sangh
Can Bore Wells Help ?
June 2004 –
Population
Land
Bore wells
Musampally village
Nalgonda District
Andhra Pradesh
3000
2000 acres
6000
No typing mistake – There are 2 bore wells per person
In this village. More than 85 % never struck water.
Others dried up soon after drilling
The Bore Wells and
The Big Dams
are the real culprits
The Bore wells have
worsened the matters
Instead of reducing
scarcity, they are
increasing it.
We have seen bore wells
- 1500 ft deep and drying
Big dams and diversion
canals are making down
stream older river
courses dry
Ural Sea in Russia
Dried by Agriculture
And Industry
?
There is certainly need
for doing everything
possible for
conserving water
Where can we learn about
water harvesting ?
What are the basic rules?
The Fundamentals ?
Any Degrees, Diplomas ?
Foreign Universities ?
?
Water Learning Points
It is available every where
In the most pure form
It is free
Yet
There is scarcity
There was no water supply department in India
till the British Government made one
… Till the British Government had to make one
Wise Water Management of our ancestors
Ancient India was Prosperous because of
Ponds and Lakes Made and Managed by People
Thus achieving water security, irrigation, flood control and food security
Modified from
Stephen Lemcke, 2002
Modified from
Stephen Lemcke, 2002
Varuna
Ganga
Modified from
Stephen Lemcke, 2002
Assi
Source - Stephen Lemcke,
e-mail: [email protected]
Water Learning Points
Marine forts have sweet water
Corresponding mainland
water is brackish
Water Learning Points
Hill Forts Have Water
Lower lands may
not have water
Are these Miracles ?
No !
There are rational explanations
Which can be put to good use
Water Learning Points
Marine forts have sweet water
Fort walls, Temple and
surroundings collect rain
water that is stored in a
huge pond.
Through a well the
harvested water is used
Jalashayanam Vishnu Temple … Mahabalipuram
Note the Rock paved surface
And drain channels as well as
The large rain water retaining
Cistern probably used as
rain gauge
Rameshwaram Temple
Note the gaps in
Foundation and the
Sweet water reflecting
the shrine
Water Learning Points
Hill Forts Have Water
Lower lands may
not have water
Water Learning Points
Hill Forts Have Water
Fortress walls help to hold
micro-water table created by a pond
Wells give the bounty in usable form
Nature offers us
our most important needs
- free of charge
Rain Water is one such thing
It is Water – in its purest form
We only need to harvest it
WHAT is Rainwater Harvesting?
Activity of capturing
the rain and storing it
for direct use or
recharging into the
groundwater.
Simply.. catching rain where it
falls and using it.
What is the need
for harvesting
rain water ?
A
natural resource presently wasted
 Prevents ground water depletion
 A good supplement to piped water
 Positive cost benefit ratio
 Relatively pollution free
 Water conservation & self-dependence
Who can harvest rooftop rainwater?
 Any
 An
person planning to build a house
independent plot owner.
 Persons
in apartments
 Industries,
Institutions and factories
 People
who are purchasing water for
domestic use
In short, everywhere
……the potential for rainwater harvesting is huge
How Much One Can harvest Rainwater ?
Vol RWH =A x R x C
A=Area
R= Rainfall in meters
C=Runoff coefficient
An example
 A =100 m2
 R = 2000 millimeters
 C = 0.85
RWH = 1,70,000 litres
Catchments details: Area, type and nature
Sr.No
Catchment
1.
Roof – flat/slope
80-90
2.
Paved area
Driveway/courtyard,
roads
Unpaved area
Lawns, garden,
playground
60-70
3
Area
(sq m)
Collection coefficient (%)
20-30
WHAT is Rooftop Rainwater
Harvesting?
Collection
 Filtration
 Storage
 Usage
 Recharge

Types of Rain Water Harvesting – 1
• Daily Harvesting
Possible in rain forests or areas with
prolonged rainy season
Collect daily – Use
Use when available
Simplest Rain Water harvesting – Use when available
During Rainy season, Drinking water needs of 35-house village
are met by a simple saree based rainwater harvesting system.
(Pic: Shree Padre)
Types of Rain Water Harvesting – 2
• Harvesting for future use
Necessary where availability is not through
out the year
Collect during rains – Store – Use
Storage can be in
2.1 - Tanks
2.2 - Soil strata
Types of Rain Water Harvesting – 2.1
• Harvesting for future use - Storage in Tanks
Used in havelis of Rajasthan/Kutcch for
centuries
Replicated in Moral Re-armament Centre
and Ion Exchange Guest house in Panchgani
Roof acts as catchment area.
Under ground Storage tanks act as collection
devices.
Usage by fetching from the tank as per need
Clean Roof
Haveli
Storage tank in the
Raised Plinth
Harvesting for Future Use – Storage in Tanks
Used in Rajasthan and Kutch
Types of Rain Water Harvesting – 2.2
• Harvesting for future use - Storage in Soil
Roof as well as open areas act as catchment
surfaces.
Inter particular spaces in soil / rocks are used
for storing water.
Water is channeled to structures made for
enhanced percolation of the harvested rain
water into soil layers
Usage – through Dug wells or bore wells
Harvesting for Future Use – Storage in Soil Strata-I
Recharge Pit
Terrace
Method
Building
Simple Ground Water
Recharge Pit
Permeable strata
Subsoil water
Ground water
Use through well/
Bore well
Harvesting for Future Use – Storage in Soil Strata-I
Recharge Pit Type 2
Terrace
Building
Recharge Pit
With a deeper shaft
Impermeable strata
Subsoil water
Ground water
Use through well/
Bore well
Harvesting for Future Use – Storage in Soil Strata - II
Recharge through Dug well
Terrace
Building
Recharge through well
Use through well/bore well
Subsoil water
Ground water
Harvesting for Future Use – Storage in Soil Strata - III
Recharge through Bore well
Terrace
Building
Recharge through bore well
Use through bore well
Ground water
Harvesting for Future Use – Storage in Soil Strata - IV
Recharge through trenches
Improved Ground water
Harvesting for Future Use – Storage in Soil Strata - V
Improving permeability of pavement
Terrace
Building
Recharge through soil
Use through well/bore well
Ground water
Selection of Rain Water Harvesting Structures
• Site Specific
• Slopes
• Geo-morphology
• Space availability
• Usage pattern
• End use specific
What is the precaution needed
If you want to harvest rain water in industrial
setting
Take care not to mix it in any way with toxic
chemicals, industrial effluents, sewage etc
Allow first flush rain water to go out of the
collection system
One Success Story :
Aachal Avichal Chanchal
• Situated at Yari Road, Andheri West
• Area prone to flooding
• YET THEY DID NOT FLOOD ON
26th July 2005
• Featured on Doordarshan / BBC
Sunshine CHS, Andheri (E)
• Storm water drainage Rainwater harvesting
Borewell recharge through storm water drainage
List of Societies/Institutes
Wishing all of you
Abundance of Pure Air
Clean water
Healthy Food
Yours Ecofriendly,
For
Eureka Forbes Institute of Environment
Vishal Bhanushali – 9869145017
[email protected]
Wishing All of you
abundance of
Clean Air
Pure Water
Healthy Food
And
Healthy Body & Rich Soul