2. contents Introduction.
Concept and Technology.
Average Rainfall of States in India.
Runoff Coefficients for Various Catchments Surfaces.
Rainwater Harvesting System.
Treatment Techniques.
Materials for Rainwater Tanks.
Components of Rainwater harvesting.
Conclusion.
3. WHAT IS water harvesting ?
It is the activity of direct collection of
rain water .
Water harvesting means capturing rain
water, where it falls and capture the
runoff from, catchment and streams etc.
Generally, water harvesting is direct
rainwater collection. This collected
water could be stored for later use and
recharged into the ground water again.
4. Rain Water in India
Total annual rainfall in India:
(area x height)
India’s area:329 million
hectares
If evenly spread, average
height: 1.28m
329 X 1.28 = 421.12millimiters
5. Average Rainfall in India
Sl.N
o
States Meteorological Divisions A A R (mm)
01
Andaman and
Nicobar Andaman and Nicobar Islands 2,967
02 Arunachal Pradesh Arunachal Pradesh 2,782
03 Assam Assam and Meghalaya 2,818
04 Meghalaya Assam and Meghalaya 2,818
05 Nagaland
Nagaland, Manipur, Mizoram an
Tripura 1,881
06 Manipur
Nagaland, Manipur, Mizoram and
Tripura 1,881
07 Mizoram
Nagaland, Manipur, Mizoram and
Tripura 1,881
08 Tripura
Nagaland, Manipur, Mizoram and
Tripura 1,881
09 West Bengal
Sub-Himalayan West Bengal and
Sikkim 2,739
Gangetic West Bengal 1,439
10 Sikkim
Sub-Himalayan West Bengal and
Sikkim 2,739
6. WHY WATER HARVESTING IS IMPORTANT
?
To conserve & augment the storage of
ground water
To reduce water table depletion
To improve the quality of ground water
To arrest sea water intrusion in coastal
areas
To avoid flood & water stagnation in
urban areas
7. Techniques of rain water harvestings.
There are two main techniques
of rain water harvestings.
Storage of rainwater on surface for future use.
Recharge to ground water.
14. Determine Tank Capacity
For Rectangular Tank
Height x Length x Width =
Cubic Feet x 7.47 = Gallons
Round Tank
π × R² × H=
Cubic Feet x 7.47 = Gallons
15. Determine the Amount of rainfall
The volume of water
collected in the pan
is:
V (m3) = L (m) x w (m) x d (m) =
1 m x 1 m x 0.010 m = 0.01 m3 or
10 liters
10 mm rainwater collected
in the container
16. Treatment Techniques
Screening
Methods Location Results
Strainers and
Leaf Screens
Gutters and
Leaders
Prevent
leaves and
other
debris from
Settling
Sedimentatio
n
Within Tank Settles
particulate
matter
17. Filtering
In-line/Multi-Cartridge
•Activated Carbon
•Reverse Osmosis
•Mixed Media
•Slow Sand
After Pump
At Tap
At Tap
Separate Tank
Separate Tank
Sieves sediment
Removes chlorine
Removes contaminants
Traps particulate matter
Traps particulate matter
Disinfecting
Boiling/Distilling
Chemical
Treatments
Ultraviolet Light
Ozonation
Before use
Within tank
After the
activated
carbon filter
•Before Tap
Kills microorganisms
Kills microorganisms
Kills microorganisms
Kills microorganisms
18. Components of a Rainwater Harvesting System
The Roof
Gutters
Gutter Guard
Downspouts
Debris Traps
Final Sediment Filtration
First Flush Diverter
Surge/Pump Tank
Water Storage
Water Disinfection
Design & Maintenance
21. The earth has an abundance of water, but unfortunately only
a small percentage (about 2.5%) is even usable by humans.
The other 97.5% is in the oceans, soils, icecaps, and floating in
the atmosphere.
Earth contains as
Sea+Oceans = 96.5%
Ground water = 1.7%
Glaciers = 1.7%
Vapor+Air = 0.001%
Only 2.5% of this water is freshwater.
Finally its very important to serve everything on
this planet