1. NEWSLETTER RAINWATER HARVESTING ISSUE 1 VOLUME 1
28TH SEPTEMBER 2011
1
RAIN WATER
HARVESTING
Rainwater harvesting is the process of
collecting, filtering and storing water from
rooftops, paved and unpaved areas for
multiple uses. This is done by storing water
in pipes and reservoirs and this works best in
drought-affected areas.
Rainwater is valued for its purity and
softness. It has a nearly neutral pH, and is
free from disinfection by-products, salts,
minerals, and other natural and fabricated
contaminants. Plants thrive under irrigation
with stored rainwater. Appliances last longer
when free from the corrosive or scale effects
of hard water. Users with potable systems
prefer the superior taste and cleansing
properties of rainwater. The harvested water
can also be used for potable purposes after
testing and treatment. The surplus water
after usage can be used for recharging
ground water aquifer through harvesting
artificial recharge techniques. This can also
result in improving the quality of the ground
water e.g. lower fluoride content in ground
water. Rainwater harvesting mechanisms are
designed after assessing the site conditions
such as incident rainfall, subsurface strata
and their storage characteristics, infiltration
test and by building suitable structures to
collect and store rainwater.
Rainwater harvesting system provides a
source of soft, high quality water, reduces
dependence on wells and other sources, and,
in many contexts, is cost effective.
Rainwater harvesting system can range in
size from a simple PVC tank to a contractor
designed and built sump - costing thousands
of dollars. Rainwater system is inherently
simple in form. Harvesting rainwater is not
only water conserving, it is also energy
saving since the energy input required to
operate a centralized water system can be
bypassed.
A range of filters for different filtration rates
have also been designed using different filter
media.
Benefit
 To prevent groundwater depletion
 To augment the expensive piped
water supply
 To save expenditure on water
 To prevent soil erosion and urban
flooding
 Inexpensive and simple technology
 Aids ecological conservation
Components of rainwater
harvesting system
 Catchment area
 Conveyance system
 First rain separator
 Filter unit
 Storage
 Delivery system
 Usage

2. NEWSLETTER RAINWATER HARVESTING ISSUE 1 VOLUME 1
28TH SEPTEMBER 2011
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Flow chart for rainwater
harvesting:
Figure 1.1 Watercycle , taken from
tradenote.net
According to a recent report on UNESCO-
IHE, underground water level has decreased.
The rainwater harvesting technique is
unique in its own sense. Water is collected
and filtration is carried out so that this stored
water can be reused latter. There are many
methods for this some of them are explained
below,
1. First flush: First flush ids the device used
to flush off the water received in first
shower. It helps in clearing silt and other
materials from the water
Figure 1.2 First flush devices
Filtration can be carried out in various ways
like,
2. Sand Gravel filter: This is a common
method used for filtration mainly by
masons, and is used by means of pebbles,
gravel and sand.
Figure 1.3 Sand gravel filter
3. PVC Pipe Filter: This filtration is carried
out by using the PVC pipe, the pipe is
divided into three compartments using
gravel, sand and charcoal.

3. NEWSLETTER RAINWATER HARVESTING ISSUE 1 VOLUME 1
28TH SEPTEMBER 2011
3
Figure 1.4 PVC Pipe Filter
4. Recharging ground water: This is done by
use of bore wells, the process which is
explained below,
Rainwater collected from rooftops is
diverted to filtration tanks where it is filtered
for further use.
Figure 1.5 filtration tank
5. Recharge pits: These are small pits of any
rectangular size made up of sand with weep
holes at regular intervals.
These Filtration methods are easy to use in
day-to-day life.
We can carry out these techniques in our
surrounding areas. These techniques help us
getting clan water for further use.
Water treatment
Figure 1.6 Takenfrom waterlink-
international.com
The above figure shows rainwater
harvesting done at the base of the house.
Specific barrels are used to stored water.
These barrels are available in various size
and shapes. Some of the barrels are placed
on the rooftops to collect water. According
to a survey done by ARCA(American
rainwater catchment association) barrels are
sold in a large quantity.
These barrels are of various types like Nino
series and villa series rain barrels, cubo and
peso series barrels etc. You can find a
variety of barrels on,
http://raintankdepot.com

4. NEWSLETTER RAINWATER HARVESTING ISSUE 1 VOLUME 1
28TH SEPTEMBER 2011
4
Examples from around the world
Germany is one of the leading countries
returning to rainwater harvesting and
has developed new and more sophisticated
systems and techniques. There is
renewed interest in the promotion of
household rainwater harvesting, especially
at the local government level, with grants,
subsidies and incentives available.
In Japan, there is growing interest in the use
of household rainwater harvesting to
provide water for firefighting purposes,
particularly in the wake of earthquakes
when mains water supplies may not be
available. In Tokyo there have been
serious investigations into the use of
rainwater harvesting in water supply, flood
prevention and disaster mitigation strategies.
If you have any ideas for future topics or
want to give feedback on our current
topic, please send an email to
rainharvesting@sbcglobal.net
Join us online and get
involved!
If you have any ideas,
examples or questions about
rainwater harvesting, please
Feel free to share them with us
on our Facebook and Twitter
pages.
We want these to be
Interactive, so the more
Contributions the better! In
return we will keep you up-to date
on all the activities going
on at the IRAH.
Upcoming Newsletter
The next edition on Rainwater harvesting
will look at our Private Sector Members.
If you have any ideas, articles
or pictures that you would like
to contribute, please send them to us at:
Newsletter rain h@yahoo.com
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please email us at:
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Us by saving rain water.
Visit our website at www.irah.org
References
This Newsletter was written
With the help of several
Articles in the area of urban
RWH. If you wish to enter the competition,
please visit our website to read the rules
of the Competition and send your
photograph/s to rainaward@irah-org.
We ask competitors to please focus on the
topic of this competition, and only
enter photographs that show the uses and
benefits of rainwater
Rainwater harvesting: Entries straying
from this theme are unlikely to win.
IRAH– International Rainwater Harvesting
II,
2300-1 Praxes, 1219, USA
Tel: +8003315151 57 & +8003315151 54
Website: www.irah-.org
Email: members@irah-.org

5. NEWSLETTER RAINWATER HARVESTING ISSUE 1 VOLUME 1
28TH SEPTEMBER 2011
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Resources
American Rainwater Catchment
Systems Association (ARCSA)
www.arcsa-usa.org
International Rainwater Catchment
Systems Association (IRCSA)
www.ircsa.org
Texas Manual on Rainwater Harvesting,
Third Edition, published July 2005
http://www.twdb.state.tx.us/publications/
reports/RainwaterHarvestingManual_3rd
edition.pdf
City of Austin Water Conservation
Program's rainwater rebates, rain
barrels, system installers or
Retailers
www.cityofaustin.org/watercon
Rainwater system manufacturers,
suppliers or installers
http://www.cityofaustin.org/watercon/do
wnloads/rwsuppliers.pdf