INTRODUCTION TO WATER
SUPPLY SYSTEM
Dr. A. K. Gupta
Professor, Environmental Engineering Division
Department of Civil Engineering
Indian Institute of Technology
Kharagpur
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IN THE NEXT FEW MINUTES…..
Introduction
Water Demands
Sources of Water
Intakes for Collecting Water
Transportation of Water and Pumping
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INTRODUCTION
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INTRODUCTION
INTRODUCTION
➢ Water is the second most important
requirement for the human life to exist
after air.
➢ Water approximately covered three-fourths
of the surface of earth.
➢ 97% of the total water supply contained in
the oceans and other saline bodies.
➢ Of the remaining 3%, 2% is tied up in ice
caps and glaciers.
➢ Only 0.62% found in fresh water lakes,
rivers and ground water supplies which are
available for drinking purpose.
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INTRODUCTION
➢ At the time of Indian Independence, i.e.,
in 1947, the per capita availability of
water in India was 6,008 cubic meters a
year.
➢ It came down to 5,177 cubic meters a
year in 1951 and to 1,820 cubic meters
a year in 2001,
➢ Per capita availability of water is likely to
fall down to 1,340 cubic meters in 2025
and 1,140 cubic meters in 2050.
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INTRODUCTION
➢ India ranks a dismal low 120th out of 122
nations for its water quality and 133rd out of
180 nations for its water availability.
➢ In addition, water scarcity in India is expected
to worsen as the overall population is expected
to increase to 1.6 billion by the year 2050.
➢ The water obtained from any of the surface
sources of water needs to be purified before
it can be supplied to the public.
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INTRODUCTION
OBJECTIVES OF PUBLIC WATER SUPPLY
SYSTEM
The main objectives of any public water supply
system are as follows:
1. To supply safe and wholesome water to the
consumers.
2. To supply water in adequate quantity.
3. To make water available within easy reach of
the consumers so as to encourage the general
cleanliness.
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INTRODUCTION
PLANNING OF WATER SUPPLY SCHEME
FOR A TOWN OR CITY
In planning a water supply scheme for a town or
city the following point need to be considered.
1. Source of water
2. Quality of water
3. Population
4. Rate of consumption
5. Topography of area
6. Financial aspect
7. Trends of future development
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INTRODUCTION
COMPONENT OF PUBLIC WATER SUPPLY
SCHEME
The various components of a public water supply
scheme are as indicated below:
1) Source of water supply-surface and subsurface
sources
2) Intakes for collecting surface water
3) Water treatment plant having screening,
sedimentation, filtration, disinfection units, etc.
4) Service reservoirs
5) Controls valves.
6) Distribution system comprising mains, submains,
branch pipelines, etc.
7) Hydrants for fire fighting, flushing streets, etc.
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INTRODUCTION
STEPS IN THE DESIGN OF WATER
SUPPLY PROJECT
1. Determination of water demand or the quantity
of water that will be required for various
purposes with the provision for the estimated
requirements of the future.
2. Reliable source of water must be located, a
treatment system must be constructed.
3. Distribution system must be provided for
delivering water to urban houses.
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WATER DEMANDS
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WATER DEMANDS
No water in Bundelkhand
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WATER DEMANDS
Latur water train Maharashtra
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WATER DEMANDS
New Delhi Demands Water
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WATER DEMANDS
ESTIMATING THE WATER DEMAND FOR
A TOWN OR CITY
The following three factors are required to be
known for estimating the water demand.
1. Rate of demand
2. Design period
3. Population
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WATER DEMANDS
Rate of Demand
It represents the average consumption or demand of water for
various purposes per person (or per head, or per capita) per
day.
The total quantity can also be expressed as:
a. Total quantity in million litres (l) or
b. Average daily demand in litres per day (l/d) or
c. average daily demand in litres per capita per day(lpcd).
Total quantity = p q 365
where p = population,
q = rate of supply in litres/capita/day
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WATER DEMANDS
Per capita use of water
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WATER DEMANDS
Design Period
➢ The future period or the number of years for which
a provision is made while planning and designing a
water supply project is known as design period.
➢ The design period should neither be too long nor
too short.
Population
➢ It represents the total number of persons residing
in a town or city at any particular time who are to
be served by the water supply project.
➢ A water supply project is planned to meet not only
the present requirements but also the future
requirements.
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WATER DEMANDS
TYPES OF WATER DEMAND
1. Domestic water demand
2. Commercial and Industrial Water Demand
3. Public Uses
4. Fire Demand
5. Loss and waste of water
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WATER DEMANDS
Hierarchy of Water Requirements
Inspired by Abraham Maslow’s (1908-1970) hierarchy of needs
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WATER DEMANDS
TOTAL QUANTITY OF WATER
REQUIRED FOR A CITY
Type of use Quantity of water (lpcd)
With full flushing With partially
system flushing system
(i) Domestic use 200 135
(ii) Commercial and 70 70
Industrial use
(iii) Public use 10 10
(iv) Loss and waste 55 55
TOTAL 335 270
Source: IS 1172-1993
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WATER DEMANDS
FACTORS AFFECTING RATE
OF DEMAND OF WATER
➢ People habits
➢ Industrialization
➢ Public services
➢ Climate
➢ System of supply
➢ Metering of water supply
➢ System of drainage
➢ Availability of supplementary sources
➢ Distribution pressure
➢ Cost of water
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WATER DEMANDS
FLUCTUATION IN DEMAND
➢ Monthly or seasonal variation
❑ In summer season the average water demand is usually 30 –
40% above the annual average rate of demand of water.
❑ In winter water demand is about 20% less than the average
demand.
❑ During rainy season the rate of water demand is also less.
➢ Daily variations
❑ The rate of demand of water also varies from day to day.
❑ During holidays like Saturday and Sunday, more water is
required.
➢ Hourly variations
❑ The demand of water also varies from hour to hour of the day.
❑ The maximum demand of water usually from morning 7 am to
9 am and in the evening 7 pm to 9 pm.
❑ Further in the early morning hours the demand of water is at
its minimum and also during noon from about 11 a.m. to 1
p.m. the demand of water is less.
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WATER DEMANDS
Maximum daily demand of water
➢ Maximum daily demand of water per head or the maximum rate of
demand of water on the day of maximum use of water (or the
maximum day of the year)
➢
➢ It is generally taken as 180% of the annual average daily demand
of water per head.
➢ Thus if q is the average daily demand of water per head, then
maximum daily demand of water per head = 180 q /100 = 1.8 q
Maximum hourly demand of water
➢ The maximum hourly demand of water per head is generally taken
as 150% of the average hourly demand of water per head on the
day of maximum use of water (or the maximum day of the year).
➢ Maximum hourly demand = (150/100)× (1.8q/24)
= 2.7 annual average hourly demand.
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WATER DEMANDS
Population Forecasts Or Population Estimates
➢ The present population can be obtained by Census
Department.
➢ The future population of a town or city at the end of
design period may be predicted on the basis of the
census data for a population, as correctly as possible.
Factors affecting Population Growth
1. Birth rates
2. Death rates
3. Migration rates.
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WATER DEMANDS
Methods of population forecasting
The various methods generally adopted for
forecasting the future population are as follows:
1. Arithmetical increase method
2. Geometrical increase method
3. Incremental increase method
4. Comparative method
5. Master plan method
6. Logistic curve method
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SOURCES OF WATER
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SOURCES OF WATER
There are two basic sources of water supply:
➢ Surface water
➢ Ground water
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SOURCES OF WATER
Various Sources of Surface Water
➢ Streams
➢ Rivers
➢ Lakes
➢ Ponds
➢ Impounding reservoirs
➢ Rain water storage reservoir/tank
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SOURCES OF WATER
Surface Water Resources of India
➢ India’s average annual surface run-off generated
by rainfall and snowmelt is estimated to be about
1869 billion cubic meter (BCM).
➢ It is estimated that only about 690 BCM or 37 per
cent of the surface water resources can actually
be mobilised.
➢ Reason for above is (i) over 90 per cent of the
annual flow of the Himalayas rivers occur over a
four month period and (ii) potential to capture
such resources is complicated by limited suitable
storage reservoir sites.
Source: National Institute of Hydrology
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SOURCES OF WATER
Quality of Surface Water
The quality of surface water depends upon
➢ Area and character of catchment
➢ Geology
➢ Topography
➢ Domestic development
➢ Time of year
➢ Sources of pollution
❖ Natural-Turbidity, colour, odour, organic
matter and dissolved solid etc.
❖ Man induced-Domestic and industrial waste
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SOURCES OF WATER
Various Groundwater Sources
The underground sources of water are of the
following four forms:
➢ Infiltration galleries
➢ Infiltration wells
➢ Springs
➢ Wells
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SOURCES OF WATER
Ground Water Resources of India
➢ The ground water resources have been estimated for
freshwater based on the guidelines and
recommendations of the Ground water Resource
Estimation Committee – 1997 (GEC-97).
➢ The total Annual Replenishable ground water
resources have been estimated as 431 billion cubic
meter (BCM).
➢ The net annual ground water availability for the
entire Country is 396 BCM (Keeping 35 BCM for
natural discharge).
➢ The Annual ground water draft is 243 BCM out of
which 221 BCM is for irrigation use and 22 BCM is
for domestic and industrial use.
Source: Ministry of water resources 33
INTAKES
FOR
COLLECTING
SURFACE WATER
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INTAKES
Intake
An intake is a device or structure placed in a surface-
water source to permit the withdrawal of water from
the source, and discharge it into an intake conduit
through which it flows to the treatment plant; or
discharge it into an intake well from where it is
pumped to the treatment plant
In general, intake consists of
1. Intake structure
2. Intake conduit with a screen at its inlet
3. Valves, gates etc.
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INTAKES
Types of Intakes
➢ Canal intakes
➢ Reservoir intakes
➢ River intakes
➢ Lake intakes
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INTAKES
Canal intake
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INTAKES
Reservoir intake
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INTAKES
River intake
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INTAKES
Lake intake
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TRANSPORTATION
OF
WATER
AND
PUMPING
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PIPES AND PUMPS
Various types of pipes
➢ Cast Iron pipes
➢ Wrought Iron pipes
➢ Steel pipes
➢ Reinforced cement concrete pipes
➢ Pre-stressed concrete (PSC) pipes
➢ Asbestos Cement pipes
➢ Copper, brass and lead pipes
➢ Plastic pipes
➢ Glass reinforced plastic (GRP) pipes
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Pipe Joints PIPES AND PUMPS
Common Type of joints
Flange joint Screw joint Flexible joint
Mechanical joint
Collar joint
Spigot and socket joint
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PIPES AND PUMPS
Structural Design of Pipes
For designing pressure pipes, the following stress
are to be taken into account:
➢ Stress due to water pressure
➢ Pressure due to self weight, overburden and
superimposed traffic load
➢ Stresses due to temperature changes
➢ Stresses due to transportation and
construction
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PIPES AND PUMPS
Pumps
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THANK YOU
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