The document discusses water harvesting techniques. It defines water harvesting as collecting and storing surface runoff for later use, which is important in arid regions where water is scarce. Traditional methods include collecting rainwater from rooftops and storing it in tanks, harvesting floodwaters, and harvesting from rivers. Modern techniques include recharging groundwater through absorption pits, trenches, and bore wells to replenish aquifers. Water harvesting provides many benefits like drought-proofing, reducing runoff and flooding, improving water quality, and conserving energy for pumping groundwater.

1. PRESENTATION
ON
Water Harvesting
Presented by:
Baniaraplang Syiemiong
(M.Sc.Forestry)
DEPARTMENT OF FORESTRY, MIZORAM UNIVERSITY, AIZAWL

2. Water Harvesting
The purpose of the stored water,
whether for domestic use, stocking
weathering, supplementary of full
irrigation.
OR
The collection and storing of water
on the surface of the soil for
subsequent use is known as water
harvesting. This include all
measures that induce, collect,
store and conserve surface runoff
in a region. Water harvesting is
most essential operation in arid
and semi arid region where water
is the deficit for most of the
season.

3. Many water harvesting structures and
water conveyance systems specific to
the eco-regions and culture has been
developed into:-
 They harvested the rain drop directly. From rooftops,
they collected water and stored it in tanks built in their
courtyards.
 From open community lands, they collected the rain
and stored it in artificial wells.
 They harvested monsoon runoff by capturing water
from swollen streams during the monsoon season and
stored it various forms of water bodies.
 They harvested water from flooded rivers

4. History
• Water has been harvested in India since antiquity, with our
ancestors perfecting the art of water management.
• Around the third century BC, the farming communities
in Balochistan (now located in Pakistan, Afghanistan and Iran),
and Kutch, India, used rainwater harvesting for irrigation.
• In ancient Tamil Nadu (India), rainwater harvesting was done
by Chola kings.
• Rainwater from the Brihadeeswara temple (located in Balaganpathy
Nagar, Thanjavur, India) was collected in Shivaganga tank
• There are evidences that, even during Harappan period, there was
very good system of water management as could be seen in the
latest excavation at Dholavira in Kachch.
• Many water harvesting structures and water conveyance systems
specific to eco-regions and culture has been developed.

5. TRADITIONAL METHODS OF WATER
HARVESTING
 Traditional rainwater harvesting, which is still
prevalent in rural areas, was done in surface storage
bodies like lakes, ponds, irrigation tanks, temple
tanks etc.
 In urban areas, due to shrinking of open spaces,
rainwater will have to necessarily be harvested as
ground water, Hence harvesting in such places will
depend very much on the nature of the soil viz.,
clayey, sandy etc.

6. Some of the Traditional Techniques
ROOF WATER:
 Slightly sloping roofs allow water to run into gutters,
down pipes, and into specially prepared drums.
 Filters of wire mesh, sand, gravel, and charcoal clean
the water. It is funneled into underground sumps or
aboveground tanks.
 Tanks are sealed to keep out air, sunlight, and organic
matter; treatment with alum reduces turbidity; and
bleaching powder kills bacteria.
 This water can be used for gardening, flushing toilets,
washing clothes

7. NAULAS:
Stone walls built across a stream to dam the
water.
Shady trees planted at the sides cut down
evaporation, and medicinal plants thrown into
the small reservoirs purify the water.
PERCOLATION TANKS, RAPATS:
 Small tanks built on sandy or rocky soil to store
rainwater.
 Some of the water is used, but the remainder
percolates through to aquifers, which replenish
wells.

8. BHANDARAS:
Underground tanks built to intercept water from
springs, channeling it to storage tanks for city use.
QANATS:
 Vertical shafts in hilly areas to catch rainwater.
The water is collected in underground channels
that carry it by gravity over long distances to
storage wells.
INTEGRATED TANKS:
 Tanks that overflow into a series of lower tanks
to catch the rainwater that is funneled through
gutters.

9. Modern Methods of Water Harvesting
 The Modern methods of rainwater harvesting are
categorized under two, they are Artificial Recharging
and Rain Water Harvesting.
 The former is classified into Absorption Pit Method,
Absorption Well Method, Well cum Bore Method and
Recharge trench cum injection well.
 The later is categorized into Individual Houses and
Grouped Houses which are further classified into
Percolation Pit Method, Bore Well with Settlement
Tank, Open Well Method with filter bed Sump and
Percolation Pit with Bore Method.

10. New Techniques
There are two main techniques of Water Harvesting
1. Storage of rain water on surface for future use
The storage of rainwater on surface is a traditional
technique and structure used in underground tanks,
ponds, check dams, weirs etc.
2. Recharge of ground water
Recharge of ground water is a new concept of
water harvesting

11. The General Structure of Recharge
Ground Water Are:-
1. Pits Recharge:
Pits are constructed for recharging the shallow
aquifers.
2. Trenches:
These are constructed when the preamble strata
is available at shallow depths.
3. Dug wells:
Existing dug wells may well be utilized as
recharge structure and water should pass
through filter media before putting into dug well.

12. 4. Hand Pumps:
The existing hand pumps may be used for recharging the shallow /
deep aquifers, if the availability of water is limited. Water should
pass through filter media before diverting it into hand pumps.
5. Recharge Shafts:
With bore wells for recharging the upper as well as deeper aquifers,
lateral shafts of 1.5 to 2m wide and 10 to 20m long depending upon
availability of water with one or two bore wells is constructed. The
lateral shafts are back filled with boulders, gravels and coarse sand.
6. Spreading Techniques:
When permeable strata start from top then this technique is used.
Spread water in streams by making check dams, cement plugs or a
percolation pond may be constructed.

13. Conclusion
Water Harvesting is used for direct usage or for recharging
aquifers. It is most important to ensure that the rainwater
caught is free from pollutants. These are the following
Benefits
1. An ideal solution to water problems in areas having
inadequate water resources.
2. The ground water level will rise.
3. Mitigates the effects of drought and achieves drought
proofing.
4. Reduces the runoff which chokes the storm water drains.
5. Flooding of roads is reduced,quality of water improves and
Soil erosion will be reduced.
6. Saving of energy per well for lifting of ground water.
7. Prevention of sea water ingress.

14. THANK YOU

15. Reference
1. Indian forestry- K. Manikandan
2. kirtifrm.blogspot.in
3. rainwaterharvesting.org
4. www-rain.blogspot.in