The document discusses rainwater harvesting as a method for collecting, storing, and purifying rainwater for future use, detailing its components including catchments and filtration systems. It also describes groundwater recharge processes, differentiating between natural and artificial recharge techniques, and outlines various methods such as basin and pit methods for enhancing groundwater levels. Additionally, it covers bandhara irrigation, a minor irrigation system that utilizes small stream structures for effective water diversion and management.

1. Water Conservation
Asst. Prof. Abhijit Hosurkar

2. Rainwater Harvesting Diagram
• Rainwater harvesting is the simple process or
technology used to conserve rainwater by
collecting, storing, conveying and purifying of
rainwater that runs off from rooftops, parks,
roads, open grounds, etc. for later use.
• Here, let us have a look at the diagram of
rainwater harvesting system.

3. Rainwater Harvesting Diagram

4. Rainwater Harvesting Diagram

5. Rainwater Harvesting Diagram
• Rainwater harvesting systems consists of the following
components:
• 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
removing pollutants.
• Tanks and the recharge structures: Used to store the filtered
water which is ready to use.

6. Rainwater Harvesting Diagram
• 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.

7. Rainwater Harvesting Diagram
• Several factors play a vital role in the amount of water
harvested. Some of these factors are:
• The quantum of runoff
• Features of the catchments
• Impact on the environment
• Availability of the technology
• The capacity of the storage tanks
• Types of the roof, its slope and its materials
• The frequency, quantity and the quality of the rainfall
• The speed and ease with which the rainwater penetrates
through the subsoil to recharge the groundwater.

8. Rainwater Harvesting Diagram

9. Rainwater Harvesting Diagram

10. Rainwater Harvesting Diagram

11. Ground Water Recharge
• Groundwater recharge or deep
drainage or deep percolation is a hydrologic
process, where water moves downward from
surface water to groundwater.
• Recharge is the primary method through which
water enters an aquifer.
• This process usually occurs in the vadose zone
below plant roots and is often expressed as a
flux to the water table surface.

12. Ground Water Recharge
• Groundwater recharge also encompasses water
moving away from the water table farther into
the saturated zone.
• Recharge occurs both naturally (through the
water cycle) and through anthropogenic
processes (i.e., "artificial groundwater
recharge"), where rainwater and or
reclaimed water is routed to the subsurface.

13. Ground Water Recharge- Basin Method
• Groundwater recharge is a technique by which
infiltrated water passes through the unsaturated
region of groundwater and joins the water table.
It is based upon soil type, land use land cover,
geomorphology, geophysical and climate (viz.
rainfall, temperature, humidity etc.)
characteristics of a region

14. Basin Method

15. Ground Water Recharge- Pit Method
• Pit Method is most suitable for such alluvial areas
(plains) where permeable strata are not below than
2 to 2.5 meter deeper from the ground surface.
• This technique is generally considered suitable for
the roof having 100 SQM areas and it is constructed
to recharge shallow aquifers.
• Recharge pits can be constructed after calculating
the quantum of rain water that can be available on
the bigger rooves.

16. Ground Water Recharge- Pit Method
• Recharge pit may be of any size and shape and this is
constructed generally with the width of 1 – 2 M, 1.5 to 2 M
deeper or according to the availability of permeable strata. This
pit is filled with layers in graded form with the boulders of 5-
20mm, gravels of 5– 10mm, thick sand/Morang (1.5 to 2mm).
• Boulders are placed on bed of the pit, gravels in middle and
thick sand is filled on top so that the silt coming in with run off
is deposited above thick sand or Morang which can be
removed later. Recharge/percolations pits for the rooves
comparatively of smaller size can be filled in with brick pieces
or pebbles etc.

17. Pit Method

18. Soil Embankment
• An earthen embankment is a raised confining structure
made from compacted soil to confine runoff either for
surface storage or for ground water recharge. These are
also used for increasing infiltration; detention and
retention of water to facilitate deep percolation and
also to provide additional storage as in the case of semi
dug-out ponds. The cross-section of embankments is
usually trapezoidal in shape. When constructed across
natural channel to induce channel storage, the
embankment also called earthen dam.

19. Soil Embankment

20. Field ponds
• A detention basin or retarding basin is an
excavated area installed on, or adjacent to,
tributaries of rivers, streams, lakes or bays to
protect against flooding and, in some cases,
downstream erosion by storing water for a
limited period of time. These basins are also
called dry ponds, holding ponds or dry
detention basins if no permanent pool of
water exists.

21. Field ponds

22. Field ponds
• Detention ponds that are designed to
permanently retain some volume of water at
all times are called retention basins. In its
basic form, a detention basin is used to
manage water quantity while having a limited
effectiveness in protecting water quality,

23. Bandhara irrigation
• Bandhara irrigation is a minor irrigation system
suitable for irrigating isolated areas, up to 500
hectares.
• The bandhara is similar to weir which is
constructed across a small stream to raise the
water level on the upstream side to divert the
water through the canal.
• The height of bandhara depends on the water
level to be raised on the upstream side.

24. Bandhara irrigation
• It is constructed with brick masonry or stone
masonry with R.C.C crest.
• The crest width varies from 1 m to 2 m.
• The scouring sluices are provided at the
bottom of the bandhara near the head reach
of the canal.

25. ADVANTAGES OF BANDHARA IRRIGATION :
• The water of small streams can be utilized for
irrigation purpose by constructing a simple
structure.
• The culturable area is generally close to the
source. Hence, there is less possibility of
transmission loss.
• As there is no loss due to transmission, the
duty of water is high.

26. DISADVANTAGES OF BANDHARA
IRRIGATION :
• Normally, the discharge capacity of small
streams is low. Moreover, if bandhara
irrigation is implemented on such streams, the
people residing on downstream side will not
get water for their use.
• The supply of water mainly depends on
rainfall. So, in the period of drought, this
system is practically useless.

27. Concrete Bhandhara

28. Concrete Bhandhara

29. • Thanks