2. Introduction
Rainwater harvesting is the process of
the accumulation & storage of the
rainwater for reuse rather than
allowing it to runoff.& it is a simple
sustainable process that helps in
preserving future needs
3. Presentation Content :
1.What is Rainwater Harvesting
2.Need of Rainwater Harvsting
3.Process of Rainwater Harvesting
4.Advantage of Rainwater Harvesting
5.Different Method of Rainwater Harvesting
4. Rainwater Harvesting
Rainwater harvesting is the simple
process or technology used to conserve
rainwater by collecting ,storing conveying
& purofying of rainwater that runss of
from the rooftop,parks,roads,open
grounds,etc.
5. Need of Rainwater Harvesting
In todays world where every kind of land is converting into
usable land for construction & covering with concrete which
is not letting the rainwater to go underground,these kinds of
activites are becoming a very huge problem for the world &
because of this most of the cities are running out of the
ground water .we have to take this this step together to
conserve water for future & the rainwater harvesting is one
of the best process to save rain water
6. Process of Rainwater Harvesting
The process of rainwater harvesting involves the collection and the storage of rainwater with the help of
artificially designed systems that run off naturally or man-made catchment areas like- the rooftop, compounds,
rock surface, hill slopes, artificially repaired impervious or semi-pervious land surface.
Catchment- Used to collect and store the captured Rainwater.
Conveyance system – It is used to transport the harvested water from
the catchment to the recharge zone.
Flush- It is used to flush out the first spell of rain.
Filter – Used for filtering the collected Rainwater and remove pollutants.
Tanks and the recharge structures: Used to store the filtered water which
is ready to use.
Rainwater harvesting systems consists of the following components:
7. Adavantages of Rainwater
Harvesting
Less cost.
Helps in reducing the water bill.
Decreases the demand for water.
Reduces the need for imported water.
Promotes both water and energy conservation.
Improves the quality and quantity of groundwater.
Does not require a filtration system for landscape irrigation.
This technology is relatively simple, easy to install and operate.
It reduces soil erosion, stormwater runoff, flooding, and pollution of
surface water with fertilizers, pesticides, metals and other
sediments.
It is an excellent source of water for landscape irrigation with no
chemicals and dissolved salts and free from all minerals.
8. In urban areas peoples uses various kinds of method to save rainwater
on the ground
There are two kinds of methods used to save water on diffrent
situation which are as :
In rooftop harvesting, the roof becomes the catchment, and the rainwater is
collected from the roof of the house/building.
Methods of Rainwater Harvesting
1.Surface Rainwater Harvesting
2.Rooftop Rainwater Harvesting
9. In this method, rainwater collected from the roof of the building &
diverted to a storage tank. The storage tank has designed according
to the water requirements, rainfall, and catchment availability.Each
drain pipe should have a mesh filter at the mouth and a filtration
system before connecting to the storage tank.Excess water could be
diverted to the recharge system. Water from storage tanks can be
used for secondary purposes such as washing and gardening etc.
This is the most cost-effective way of rainwater harvesting.
DIFFERENT METHODS OF RAINWATER HARVESTING
1.Direct Storage Method
There are many kind of methods used in rainwater harvesting wahich are as
follows:
(Note-this water is only usable for gardening,washing .it can't be usable in drinking)
10. Recharge pits are small pits of any shape rectangular, square, or circular
contracted with brick or stone masonry wall with weep hole at regular
intervals. Top of the pit can be covered with perforated covers. The
bottom of the pit should be filled with filter media.These pits are suitable
for recharging of shallow aquifers, and small houses.
2.Recharging in Borewell Method
Rainwater collected from the rooftop of the building is
diverted through drain pipes to settlement or filtration tank.
After settlement, filtered water is diverted to bore wells to
recharge deep aquifers. This method has required huge
space for execution.
3.Recharge Pit Method
11. 4.Soakways or Recharge Shaft Method
This method is used at a huge space & very effecting in
saving water Soak away, or recharge shafts are provided
where the upper layer of soil is alluvial or less porous. These
are the bored hole of 30 cm dia. up to 10 to 15 m deep,
depending on the depth of the pervious layer. Bore should
be lined with slotted/perforated PVC/MS pipe to prevent the
collapse of the vertical sides.
5.Recharging of Dugwell method
Dug wells can be used as a recharge structure. Rainwater
from the rooftop is diverted to drilled wells after passing it
through the filtration bed. Cleaning and desalting of dug
well should be done regularly to enhance the recharge
rate. The filtration method suggested for bore well
recharging could be used.
12. The recharge trench is provided where upper impervious layer of soil is shallow. The
recharge trench excavated on the ground and refilled with porous media like pebbles,
boulders, or brickbats. It is usually made for harvesting the surface runoff.Bore-wells
can also be provided inside the trench as recharge shafts to enhance percolation. The
length of the trench is decided as per the amount of runoff expected.This method is
suitable for small houses, playgrounds, parks, and roadside drains. The recharge trench
can be of size 0.50 to 1.0 m wide and 1.0 to 1.5 m deep.
Percolation tanks are artificially created surface water bodies, submerging
a land area with adequate permeability to facilitate sufficient percolation
to recharge the groundwater. These can be built on big campuses where
land is available, and topography is suitable.Surface runoff and roof
topwater can be diverted to this tank. Water accumulating in the tank
percolates in the solid to augment the groundwater.The stored water can
be used directly for gardening and raw use. Percolation tanks should be
built in gardens, open spaces, and roadside greenbelts of urban areas.
6.Recharge Trenches
7.Percolation Tank Method