1) Rainwater harvesting systems collect rainwater from rooftops through gutters and pipes into a storage tank. 2) The typical components are a roof, gutters, a first flush diverter, and a storage tank, which can be underground or above ground. 3) Depending on the roof area and annual rainfall, a 3,000 liter tank may be able to collect all the 50,000 liters of rainwater that falls on a 100 square meter roof in a place with 500 mm of annual rain.

1. Subject: BUILDING SERVICES (3360604).
Topic: “RAIN WATER HARVESTING”
Prepared by: Bhavesh hathila
Government Polytechnic, Dahod

3. SYSTEM COMPONENTS
What are the parts of the roof top rainwater harvesting
system?
• ROOF –
The existing roof is made use of to collect
rainwater.

4. • PVC GUTTERS:
The gutters of PVC collect the rainwater from
the roof and transfer it to the filter.

5. • FIRST RAIN SEPARATOR:
The first rain separator or a washout pipe as it
is called, has a valve or an end cap to allow the
first little amount of rainwater to be collected

6. • STORAGE TANK:
The rainwater storage tank collects all the
filtered rainwater and keeps it for future use.
The storage tank is made above the ground
and on a platform. It can also be an
underground sump in some cases.

7. How much rainwater can be collected?
• This depends on the rooftop area, the size of the
tank and the rainfall at that place. For example in
a place where it rains 500 mm and the roof area
is 100 square meters, the rainwater falling on the
roof is 50,000 liters.
• Depending on the size of the rainwater tank and
the distribution of rainfall even a 3000 liter tank
may be sufficient to collect all this 50,000 liters of
rainwater. We must however keep on using the
rainwater in the tank and not wait for summer to
use it.

8. 1)Rainwater harvesting technologies are simple to
install and operate.
2)Local people can be easily trained to implement
such technologies, and construction materials are
also readily available. Rainwater harvesting is
convenient in the sense that it provides water at the
point of consumption, and family members have full
control of their own systems, which greatly reduces
operation and maintenance problems.

9. 3) Water collected from roof catchments usually is of
acceptable quality for domestic purposes.
4)As it is collected using existing structures not
specially constructed for the purpose, rainwater
harvesting has few negative environmental impacts
compared to other water supply project technologies
5)Depending upon household capacity and needs,
both the water collection and storage capacity may be
increased as needed within the available catchment
area.

10. Methods of rain water harvesting:-
There are seven methods of harvesting:-
1) Check dam
2) Field pit
3) Percolation tank
4) Ponds
5) Rain water harvesting by strong water from roof
6) Vegetation and plantation
7) Nala planging

11. A check dam is a small, sometimes temporary, dam
constructed across a swale, drainage ditch, or waterway to
counteract erosion by reducing water flow velocity. Check
dams themselves are not a type of new technology; rather, they are
an ancient technique dating all the way back to the second century
A.D. Check dams ...
1)Check dam

12. Tradescantia ohiensis, known variously as the bluejacket
or Ohio spiderwort. In angiosperm: Structural basis of transport
…cell walls at areas called primary pit fields. Also, some
substances pass out of cells into the apoplast and are transported
by energy-requiring processes into the protoplast of another cell.
Read More.
Field pit

13. The State of Maharashtra is divided into five river basins,
namely Godavari, Krishna, Tapi Narmada, and westerly flowing
rivers in the Konkan Coastal Strip (Fig. 1.8). The total area
covered under these basins is 30.88 million hectares (mha), of
which 22.54 mha can be cultivated. The water availability in these
river basins annually on an average is 131.56 Billion Cubic Metre
(BCM). To harness the above surface water potential, various
major dams, medium projects and minor tanks have been
constructed. Water from the dams is supplied for the different
needs of agriculture, domestic and industrial. At the strategic level,
Water Resource Development (Erstwhile, Irrigation Department,
Government of Maharashtra) through five Irrigation Development
Corporations (IDCs) is responsible for managing the surface water
resources and it allocates water for irrigation, industrial, drinking
and sanitation, purpose.
Percolation tank

15. A pond is a body of standing water, either natural or
artificial, that is usually smaller than a lake. They may arise
naturally in floodplains as part of a river system, or they may be
somewhat isolated depressions (examples include vernal pools
and prairie potholes). They might contain shallow water with
marsh and aquatic ...
Ponds