rain water harvesting

1. ONLY WHEN THE LAST RIVER HAS BEEN POLLUTED,
AND THE LAST TREE BEEN CUT DOWN,
AND THE LAST FISH BEEN CAUGHT,
WE WILL REALIZE WE CANNOT EAT MONEY.
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2. RAIN WATER HARVESTING
An investment for next generation

3. UNIVERSITY OF AGRICULTURAL SCIENCES,
BENGALURU.
COLLEGE OF AGRICULTURE, HASSAN.
FARM MECHANIZATION NRM405 (0+5)
Submitted to:
Dr. Narayanaswamy. T
Mr. Shivabasappa
Dept. Of Agricultural Engineering ,
College of Agriculture, Hassan.
Submitted by:
Vivek. S
ALH5089
IV Bsc Ag (Hons)
College of Agriculture, Hassan.
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4. INTRODUCTION
• In the present scenario management and distribution of
water has become centralised.
• Fresh water today is a scarce resource, and it is being felt
world over.
• According to UNEP (United Nations Environment
Programme) more than 2 million people would live under
conditions of high water stress by the year 2050.
• India has been notorious of being poor in its management of
water resources and demand is already outstripping the
supply.
• As the water crisis continue to become severe, there is a dire
need of reform in water management system and revival of
traditional system.
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5. What is Rainwater Harvesting?
• “The conscious collection and storage of
rainwater to cater the demands of water for
drinking, domestic purpose and irrigation is
termed as Rainwater Harvesting”
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6. Why harvest Rainwater?
• To arrest ground water decline
• To augment ground water table.
• To beneficiate water quality in aquifers.
• To conserve surface runoff during monsoon.
• To reduce soil erosion.
• To inculcate culture of water conservation.
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7. How to harvest Rainwater?
Two ways of harvesting rainwater:
• Surface runoff harvesting
• Rooftop rainwater harvesting
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8. Surface Runoff Harvesting
It can be done in two ways-
 Storage of rain water for direct use.
• In this method rain water is collected in a storage tank.
• The tank has to be designed according to the water
requirements, rainfall and catchment availability.
• Tank should have excess water outflow system.
• This stored water can be used for the secondary purpose like
washing, gardening etc.
• This is the most cost effective way of rainwater harvesting.
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9. Recharging ground water aquifers
• Ground water aquifers can be recharged through
various methods.
• Commonly used recharging methods are-
i. Recharge Pits
ii. Recharge Trenches
iii. Recharging Dug wells
iv. Percolation Tanks
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10. a) Recharge Pits
• Recharging pits are constructed for recharging the
shallow aquifers.
• These are 1 – 2m wide 3m deep which are backfilled
with boulders, gravel, coarse sand.
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11. b) Recharge trenches
• These are constructed when permeable stream is
available at the shallow depth.
• Trenches are 0.5 – 1m wide, 1 – 1.5m deep and 10 –
20m long.
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12. c) Recharging dug wells
• Dug well can be used as a recharge structure.
• Rainwater from rooftop is diverted to dug well after
passing it through the filtration bed.
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13. d) Percolation tanks
• These are artificially created surface water bodies to
recharge ground water.
• Surface runoff and roof top water can be diverted to
this tank.
• Water accumulating in the tanks percolates to
augment the ground water.
• The location of the tanks should be in natural
depressions requiring lesser land aquisition.
• The stored water can also be used directly for
gardening and raw use.
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14. 14

15. Rooftop Rainwater Harvesting
• It is a system of catching rainwater where it falls.
• Here roofs are the catchment.
• Rain water collected from the roof is stored either in
a tank or diverted to artificial recharge system.
• This method is less expensive.
• If implemented properly helps in augmenting
ground water level of area.
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16. 16

17. Components of Roof water Harvesting
System
• Catchment – The surface which receives the
rainfall.
• Transportation – Rainfall from catchment is
carried through water pipes or drains to
storage/harvesting system.
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18. First Flush – Device used to flush of the water used in
the first shower.
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19. Filter – It is used for the treatment of the water to
remove turbidity, colour and microorganisms.
After first flushing of rainfall, water should pass
through filters.
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20. TYPES OF FILTERS
• SAND GRAVEL FILTER
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21. • CHARCOAL FILTER
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22. • SPONGE FILTER
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23. •PVC PIPE FILTER
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24. ECONOMICS OF RAINWATER HARVESTING FOR
INDIVIDUAL HOUSE OF < 100m2
• Method used – Recharging pit method
• Pit size – 1* 1* 1
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25. RAINWATER HARVESTING OF MULTISTORIED
BUILDING OF SIZE 20*30 m
• Method – Recharging trench method
• Trench size – All around building 1*1*1.5m
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26. CONCLUSION
• Sustaining and recharging ground water along with
the judicious use is need of an hour.
• One of the most logical step towards this is
acknowledging about Rain water harvesting.
• We have to catch water in every possible way and
every possible place it falls.
• It can be concluded that rainwater, if conserved and
utilized , can be an effective tool of replenishing
ground water resources.
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27. REFERENCES
• A Water harvesting manual for urban areas: Case
studies from Delhi 2003, Centre of Science and
Environment.
• A Water Harvesting Manual, Centre of Science and
Environment.
• http:/www.rainwaterharvesting.org/
• Government of India. 2003. Rain Water harvesting,
Central Water Control Board, Ministry of Water
Resources.
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28. SAVE THE WATER OF RAIN AND
DONT LET IT TO DRAIN....
THANK YOU