Water as a Resource
Lectuer:1
Building Services
B .Arch-II , Sem-III
Introduction
At global scale, about 71% of earth surface is covered with water.
From total volume of water in hydrosphere 97% is ocean water (unsuitable for human
use due to high proportion of salt contents in it) and rest 3% is the availability of fresh
water which is available from ice caps, rain water which is distributed in lakes, rivers
and streams.
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B .Arch-II , Sem-III
Source of Water
Sources of the water are broadly classified in two categories.
Surface water
Ground water
Surface water is water collecting on the
ground or in a stream, river, lake.
Groundwater is water located beneath the
ground surface in soil pore spaces .
It also known as subsurface water resources.
Classification of surface water is as follows
a) Streams
b) Lake & Ponds
c) Rivers
d) Impounded reservoirs
e) Stored rainwater and cisterns
It can be further divided as
a) Springs
b) Infiltration galleries
c) Porous pipe galleries
d) Wells
Building Services
B .Arch-II , Sem-III
•
Surface water
STREAMS
A stream is a flowing body of water.
In mountainous regions streams are formed by the runoff.
The discharge in streams is much in rainy seasons than
other seasons.
When water is flowing over ground is mixed with clay, sand
and mineral impurities. All suspended impurities can be
removed in setting tanks, but the dissolved impurities
require special treatments.
Surface water
•
LAKE & PONDS
In mountainous regions at some places natural basins are
formed with impervious beds.
Water from springs and streams flows towards basin and
‘lakes’ are formed.
The quantity of water depends on its basin capacity,
catchment area, rainfall etc.
his water will required very primary treatment for its use.
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B .Arch-II , Sem-III
Surface water
•
RIVERS
A river is a natural watercourse, usually freshwater.
Rivers are born in the hills, when the discharge of large number of springs and streams
combine together.
In ancient time the town and city started developing along the bank of rivers.
Mostly all the cities which are situated near rivers discharge their used water or sewage in
the rivers, therefore much more care should be taken while drawing water from the river.
River water has self purification action due to which it automatically becomes clean in
some distance travel from the point of disposal of sewage. But the river water should
always be used after necessary treatments.
Building Services
B .Arch-II , Sem-III
•
Surface water
IMPOUNDED RESERVOIRS
Mostly it is found that there is great variation in the quantity
of river water during monsoon and summer seasons. The
discharge in some rivers cannot meet the requirements of hot
seasons. In such cases it becomes essential to store the water
for summer season.
The water can be stored in the river by constructing a weir
or a dam across the river which creates the cup-shaped
reservoir basin having maximum possible depth of water
which is known as impounded reservoirs.
Surface water
•
STORED RAIN WATER AND CISTERNS
At some places where neither ground water nor surface
water is easily available, the only way is to store the rain
water in cisterns or tanks from roofs of buildings.
The rain water from roofs is collected in water tight tanks.
Water obtained in this way is extremely soft and reasonably
clean.
The quality of water stored in this way is limited and can not
be utilized for water supply distribution on large scale.
Building Services
B .Arch-II , Sem-III
•
Ground water
SPRINGS
It occurs, when the surface of earth drops sharply below the normal ground water table.
•
INFILTRATION GALLERIES
The ground water travels towards lakes, rivers
or streams. This water can be interrupted by
digging a trench or by constructing a tunnel
with holes on sides at right angle to the
direction of flow of underground water. These
tunnels are known as infiltration galleries.
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B .Arch-II , Sem-III
Ground water
•
POROUS PIPE GALLERIES
Where there is large quantity of ground water existing over a
wider area, it can be cheaply collected by laying porous pipes
or pipes with open joints in the full area at some distances.
Ground water
•
WELLS
Depending upon the method of
construction wells are classified
as follows.
•Dug well or percolation well
•Driven well
•Tube well
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B .Arch-II , Sem-III
Water Treatment Process
&
Water Demand
Lectuer:2
Building Services
B .Arch-II , Sem-III
Water treatment process
The treatment process directly depends on the impurities present in water. For
removing various types of impurities the following treatment process are used.
Impurities
Process
Floating matters as leaves, dead screening
animals etc.
Suspended impurities as silt, clay, Plain sedimentation
sand etc.
Fine suspended matter
sedimentation with coagulation
Micro organism and colloidal Filtration
matters
Dissolved gases and odours
Aeration and chemical treatment
Softening
Permutit method
Pathogenic bacteria
disinfection
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B .Arch-II , Sem-III
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B .Arch-II , Sem-III
Water demands
Before designing any water supply scheme one should know the water demand.
i.e the requirement of water followed by finding various sources to fulfill the
demand.
There are different types of water demands.
•Domestic water demand
•Commercial and industrial demand
•Fire demand
•Demand for public uses
•Compensate losses demand
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B .Arch-II , Sem-III
•Domestic water demand:
It includes the mainly of water required in the houses for drinking, bathing, cooking,
washing etc.
Drinking
Cooking
Bathing
Clothes washing
Utensil washing
House washing
Flushing of W/C
Total
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5 lit
5 lit
55 lit
20 lit
10 lit
10 lit
30 lit
135 lit/ capita/ day (Lpcd)
B .Arch-II , Sem-III
•Commercial and industrial demand:
The water requirements of commercial and public places may be up to 45 lit/ capita/ day.
1.Factories
Factories where bathrooms are required to be provided
Factories where no bathrooms are required to be provided
2.Hospitals (including laundry) per bed
Less than 100 beds
More than 100 beds
3.Nurse homes and medical quarters
4.Hostels
5.Offices
6.Restaurants (per seat)
7.Hotels (per bed)
8.Cinema concert halls and theatres (per seat)
9.Schools
Day school
Boarding school
10.Garden, sports grounds
11.Animals/vehicles
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45
30
340
450
135
135
45
70
180
15
45
135
3.5 per sq.m
45
B .Arch-II , Sem-III
•Fire demand:
It is calculated by the formula derived by National Board of Fire. It is depending upon the
population of town. In India we are following Kuichling’s formula to find demand.
It is generally kept 15 lit/ capita/ day.
•Demand for Public uses:
Quantity of water required for public utility purposes such as for washing roads,
cleaning of sewers, watering of public parks, gardens, fountains etc.
Public park
1.4 lit /m2/ day
Street washing
1to 1.5 lit /m2/ day
Sewer cleaning
4.5 lit/capita / day
•Compensate losses demand:
While estimating the total requirement of water considered allowance for the
losses like
-defective, cracked pipe joints & pipes,
-faulty valves & fittings,
-wastage of water
-some unauthorized & illegal connections.
We are considering 15% of total quantity of water to compensate such losses.
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B .Arch-II , Sem-III
So for average Indian town the requirement of water is as under:
Domestic use
Commercial & Industrial use
Public uses
Fire demand
Losses, wastage & thefts
Total
Building Services
135 lit/ capita/ day
40 lit/ capita/ day
25 lit/ capita/ day
15 lit/ capita/ day
55 lit/ capita/ day
270 lit/ capita/ day
B .Arch-II , Sem-III
Water Distribution System
Lectuer:3
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B .Arch-II , Sem-III
Method of distribution
For efficient distribution it is required that water should reach to every consumer with
required rate of flow.
The distribution system classified as follows:
•Gravity system:
The method is suitable when sources of supply such as lake, river or impounding
reservoirs are at sufficient height then city. The water flows in the mains due to
gravitational force.
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B .Arch-II , Sem-III
•Pumping system:
In this system water is directly pumped in the mains.
So this system requires pumps & therefore continues watch and maintenance is
required.
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•Dual system:
This is also known as combined gravity and pumping system. In this process the
pump is connected to the mains leading to an elevated reservoirs or tank. In the
beginning when demands is small the water is stored in the elevated tank and flows
in distribution systems, but when demand increases the flow in the distribution
system comes from both the pump house as well as elevated tank. So it is called dual
system.
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B .Arch-II , Sem-III
Layout of distribution system
Depending upon their layout and direction of supply, there are classified as follows.
•Dead end or tree system
•Grid iron system
•Circular or ring system
•Radial system
Building Services
B .Arch-II , Sem-III
•Dead End or Tree system:
 It is suitable for irregular developed towns & cities.
 In this system one main starts from reservoir along the main road.
 Than it is divided in sub mains in both the directions, which will connected to
the individual houses by means of branches and sub branches.
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B .Arch-II , Sem-III
•Grid – iron system:
 This system is also known as reticulated system and is most convenient for town
having rectangular layout of roads.
 This system is an important over dead end system.
 All the dead ends are interconnected with each other and water circulated freely
through out the system.
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B .Arch-II , Sem-III
•Circular or ring system:
This system can be adopted only in well planned locality of cities.
In this system each locality is divided in to square or circular blocks and the water
mains are laid around all four sides of the square or round of the circle.
All sub mains, branches and sub branches are taken from the boundary mains
and all are interconnected.
In this way every point receives its supply from two directions.
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Radial system:
This is the reserves of ring system and water flows from inner point to outer periphery.
The entire district is divided into various zones one reservoirs is provided for each zone,
each is placed in the centre of zones. The water lines are laid radially from it.
Building Services
B .Arch-II , Sem-III