Microsoft PowerPoint - Ch7-E4 E5 civil Concept of Water Cons & Rain Water Harvesting. [Compatibility Mode]E4E4--E5 CIVIL E5 CIVIL
Concept of Water Conservation Concept of Water Conservation & Rain Water Harvesting& Rain Water Harvesting
WELCOME
Module for the Topic: Concept of Water Conservation &
Rain Water Harvesting.
E4 to E5.
• This presentation is last updated on 21-4-2011.
• You can also visit the Digital library of BSNL to see this
topic.
AGENDA
Different Harvesting Methods
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• Rahiman Pani Rakhiyo, Bin Pani Sab Soon
• Paani Gaye Na Ubre, Moti Maanas Choon.
• Rakhiyo – To Protect
Importance of Water
• Next to air, water is the only other resource in the
nature which sustains life on Earth. If we can not
live without air for more than a few minute, we can
not live without water form more than a few hour.
Life without water is impossible, with scare water
extremely hard and with water is blessing. In
reorganization of this fact Nature has covered two-
third of our planet with water.
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Importance of Water
industrialization as led to its acute shortage at an
alarming rate.
• Lowering of water table leading to drying up of bore
wells has become common occurrence.
• Government of India has since undertaken a
number of steps aimed at preventing its excessive
mining and harvesting and conservation.
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Availability of Water
3%
97%
• In fact the total freshwater available on earth is only
3% as against 97% saline water in Oceans. Out of
this 3% fresh water, 77% water is in the form of
glaciers and icecaps, 11% water is in deep aquifers
which is 800 meters below ground and only 12% is
available for drinking and other purpose out of
which 11% is in acquires which are up to 800
meters below ground and remaining 1% is available
in rivers, lakes, ponds and streams.
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What is RWH
and storage of rain water of surface or in sub-
surface aquifer by recharging it for future
requirement so that it is not lost as surface run-off.
Rain water is the purest form of raw water available
on the earth.
Solution of Water Problems
appropriate use of Rain water harvested through
roof and from built up catchments where annual
rainfall is sufficient. It has been estimated that the
amount of rain water that falls on the terrace of a
medium house can take care of the drinking-water
requirement of an average family of four members
for one year.
Advantages of Rainwater Harvesting
enhancing the availability.
• Provides sufficient water for home needs
• Reduction in flooding and drainage problems.
• To arrest seawater ingress.
• Improves the underground water quality.
• Saves the energy for lifting ground water.
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Rainwater Harvesting Systems :
harvesting rainwater: Conservation by providing
storage tank on the ground or under ground and
recharge of aquifer.
either of these two techniques or a combination of
both depending upon various factors as shown (In
next slide).
Rainwater Harvesting Systems
RAIN WATER
within 1-2m from the ground surface.
• This is ideally suited for small buildings up to 100 sq. m
roof top area.
• These are generally constructed 1-2m wide and 2-3m
deep.
boulders.
Methods of Rainwater Harvesting
RECHARGE PIT
thickness are available at shallow depth and the roof
area of the building is 200-300sqm.
• Recharge trench can be of any dimensions.
Generally it is 1-1.5m deep, 0.5-1m wide and of any
length depending upon the availability of water to be
recharged.
Methods of Rainwater Harvesting
shaped, U shaped.
the top for filtration of water.
• The sides of the trench should slope at low angle
for stability.
Methods of Rainwater Harvesting
Methods of Rainwater Harvesting
technique to recharge unconfined aquifer overlain
by poorly permeable strata.
• This is like an open well but filled with filter media.
• Diameter of the shaft generally varies from 1-3m
depending upon the availability of the water to be
recharged.
Methods of Rainwater Harvesting
• It is constructed where the aquifer to e recharged is
located at medium depth.
recharged. It may not touch the water table.
• In the upper portion of 1-2m depth, the brick
masonry work carried out for the stability of the
structure.
Methods of Rainwater Harvesting
Methods of Rainwater Harvesting
multiple aquifers are met interspersed with
impervious strata.
assembly is used and it should have the provision
of slotted pipes against the water bearing strata.
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Methods of Rainwater Harvesting
gravity flow conditions.
roof top area and aquifer characteristics.
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Methods of Rainwater Harvesting
Methods of Rainwater Harvesting
Methods of Rainwater Harvesting
after cleaning & de-silting the same.
• A filtration chamber may be constructed so that the
water can be made silt free before entering the dug
well.
• The recharge water is guided through a pie to the
bottom of the dug well and it is converted into dug-
cum-bore well.
Methods of Rainwater Harvesting
the roof area more than 1000sqm from where the
rain water can be diverted and recharged.
• Periodic chlorination should be done for controlling
the bacteriological contaminations.
Methods of Rainwater Harvesting
recharge structure.
having roof area up to 150sqm.
• Water is diverted from the roof top to the hand
pump through pipe of 100 mm dia.
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Methods of Rainwater Harvesting
monsoon runoff can be impounded by constructing
bunds on the sloping ground all along the contour of
equal elevation.
erosive velocity by keeping suitable spacing
between the bunds.
Methods of Rainwater Harvesting
• Spacing between the two contour bunds depends
on the slope of the area as well as the permeability
of soil.
slopes without involving terracing.
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Cost of Rain water Harvesting
• The cost of implementation of rainwater harvesting
systems in a house/flat complex will vary from
Rs.5000 – Rs.50,000 depending on the size of the
premises as well the nature of the soil. Once put in
place, the harvesting structure do not require any
serious maintenance and hence there is no
recurring expenditure involved.