A simple Presentation for new learners...an introduction to rainwater Harvesting

1. Rain Water Harvesting...rain catchers.
Hitesh M. Majithiya
Email: hmajithiya@gmail.com

2. Contents
1. Introduction.
2.Need for Rainwater Harvesting.
3. Advantages of RWH
4. Where Rain Water Harvesting ?
5. Methods for Rainwater Harvesting.
6. Water Conservation Tips…
5. Lessons Learnt

3. Water is unique in our natural resources although it is
renewable, it is not replaceable. We have various
substitutes for energy sources, but there is no substitute for
water.
Once it is gone or degraded through overuse or pollution, it
cannot be substituted.

4. Amount of drinking water in world

5. •Water Crises in the world
1. Water stress results from an imbalance between water use and
water resources.
2.A United Nations report predicts that access to water may be the
single biggest cause of conflict and war in Africa in the next 25
years.
3.All three rivers feeding China's Northern Plain are severely
polluted, damaging health and limiting irrigation.
4.More than half of Europe's cities are exploiting groundwater at
unsustainable rates. Chronic water shortages are already affecting
4.5million people in Catalonia.
5. Competition for water from the River Jordan was a major cause
of the 1967 war in Middle East.

6. Per capita consumption – India / World
Liters per person per day
Drinking 3
Cooking 4
Bathing 20
Flushing 40
Washing clothes 25
Washing utensils 20
Gardening 23
Total 135 liters

7. Rainfall in India
India annual
rainfall
is within the
top 6 countries
in the world.
“But we do not
conserve the
Rain Water”

8. India has TWO disastrous seasons…
Flood & Draught

9. Introduction
What is Rainwater Harvesting (RWH) ?
“Capture rain water, store it & use it…it is as simple as that”
OR
“Rain Water harvesting is technique of collection, storage & use of rain water at
surface or sub-surface before it is lost as runoff ”
• Commonly used systems are constructed of three principal components;
namely,
• The catchments area.
• The collection device, and
• The conveyance system.

10. Need for RWH ???
 Continues failure of rainfall & consequent deficit of rainfall.
 Because it cost less to collect rainwater than to exploit ground
water.
 Increased population α More water demand = Depletion of
ground water table.
 In some parts Excessive heat waves creates drought condition.
 So Rain Water Harvesting is need of the hour due to decreasing
trend of GROUND WATER i.e. well, lake, tubewells etc.

11. Advantages of RWH
•It can complete our present water demand.
•It reduces flood hazard.
•It reduces the drought effects.
•It increases level of ground water table.
•It reduces soil erosion.
•Underground water storage is ecofriendly.
•Rainwater harvesting technologies are simple to
install and operate.

12. Where Rain Water Harvesting is required ?
• Ground water levels are declining on regular basis.
• Areas where inadequate amount of water in lean
months.
• Where due to rapid urbanization, infiltration of
rain water into subsoil has decreased drastically &
recharging of ground water has diminished.
• RWH is essential where ground water get
saturated with high Iron & fluoride content.

13. Methods for Rainwater Harvesting
1. Roof top Rain water Harvesting & storage
in tanks.
2. Roof top Rain water Harvesting & and
recharging of surface aquifers i.e. dams,
lakes etc.
3. Surface runoff harvesting and recharging
of sub surface aquifers.

14. RWH Calculation
To calculate the approximate amount of rainwater you are likely to harvest,
use the following formula:
Roof area in sq. meters x Rainfall in mm x 0.8 (Coefficient factor)
For e.g.: 100 m2 x 1000 mm rainfall x 0.8 = 80,000 liters
= 80 Cubic meter
Note:-1. Tank size should be 5 % of annual rainfall.
2. Flush first rainfall to clean rooftop.

15. 1. Roof top Rain water Harvesting, storage & Use
a. Rain water collects on roof top.
b. This water is guided into overflow pipe.
c. These pipes connect to rainwater storage tanks.
d. Water can be access through bucket or pumps using filters.

16. 2. Roof top Rain water Harvesting & and recharging of surface
aquifers i.e. dams, lakes etc

17. 3. Surface runoff harvesting and recharging
of sub surface aquifers.

18. Water Conservation Tips…
• Install small shower heads to reduce the flow of the water. At the end
of the day if you have water left in your water bottle do not throw it
away, pour it over some plants.
• While brushing or other use, do not leave the tap running, open it only
when you require it. See that there are no leaking taps.
• Do not leave the taps running while washing dishes and clothes.
• Re-use water as much as possible.
• Change in attitude & habits for water conservation.
• Because every drop counts!!!
• MOST IMPORTANT BEYOND RWH, “PLANT TREES” THIS
ONLY CAN BRING RAIN.

19. Lessons learnt…
1. Rainwater can be collected where it falls & reuse it at marginal cost.
2. This is the only long term solution to draught proofing places against water
scarcity.
3. We have management & control over the water not the government.
4. RWH must be understood & replicate everywhere in the world where there is
acute water shortage.

20. Still we have time to face this situation…!!!
LET’S TRY TO MAKE WATEREVERYBODY'S BUSINESS.

21. Thank you!!!