Water Supply Engineering

Chapter 1: Introduction
 Outline
Ø Introduction
Ø Importance of Water
Ø Definition of Types of Water
Ø Historical Development of Water Supply System
Ø Objective of Water Supply System
Ø Schematic Diagram of Typical Water Supply System
Ø Components of Water Supply System and Their
Functions
Introduction
World water distribution
Distribution of accessible fresh water
Introduction

Per capita
water supply
in
Kathmandu
Valley at
just 34 liters
a day
 Importance
Ø Survival of every organism begins with water. Air and water are the natural
gift. Everywhere water is needed for various purposes as follows:
• Drinking and cooking
• Domestic purpose like bathing, washing and flushing, watering lawns and
gardens
• Heating and air conditioning system
• Street washing
• Fire fighting
• Transportation
• Irrigation
• Recreation in swimming pools, fountain and cascades
• Power generation and various industrial process.
 Types of water
Pure Water
• It is the water containing two parts of hydrogen and one part of
oxygen.
• It is not good for health, not suitable for drinking purpose as it
lacks vital minerals required for the human growth.
• It doesn’t contain any other substances, any kind of
minerals, salts, gases, microorganism etc.
• Used for medical and laboratory purposes.
• Obtained by distillation and by chemical action in labarotories.

Impure water:
• It is the water which has other substances mixed with it.
• It contains impurities and minerals.
 Types of water
Potable water:
• It is water s a f e a n d suitable for drinking, having pleasant taste and useable for
domestic purposes.
• It should be clear, free from suspended materials and should not contain any
bacteria and excess of dissolved impurities.
• It may contain bad smell and color but does not impact on heath.

Palatable water:
• It is water which is tasteful for drinking and astheticaly pure.
• It is water at a desirable temperature that is free from objectionable tastes, odors,
colors, and turbidity.
• It is synonymous to potable water.

Note: Water that is safe to drink but may smells like rotten eggs is potable. Water that
is safe to drink and is odorless is palatable.
 Types of water
Polluted water:
• It is the one which contains substances unfit or
undesirable for public health or domestic purposes.
• It contains excessive impurities and number of
harmful bacteria.

Contaminated water:
• Contaminated mean containing harmful matter.
• It may appear clean and clear but contain micro organisms,
chemicals, waste, large number of pathogens causing
diseases.

Infected water:
• Water contaminated with pathogenic organisms is called
infected water.
 Types of water
Wholesome water:
Ø Water that is free from all poisonous substances and contamination which is fit for
drinking, cooking, washing etc. without any potential danger and meets the
standard of regulation is called Wholesome water.
Ø It should have following requirement:
• Should be free from radioactive substances, disease causing bacteria and
other pathogenic organisms, objectionable minerals and dissolved gases.
• Should be colorless, odorless and cheap.
• Should be tasty, cool, sparkling.
• Should not be corrosive in nature.
• Should not contain harmful dissolved impurities.
• Should contain dissolved oxygen and free carbonic acid so that it may
remain fresh up to specific range.
• pH should be balanced.
 Historical development
• During the early ages the civilization start to develop around the places where
water were plentiful such as rivers or natural springs.
• With the time , the population increased causing the expansion of civilization and
people were compelled to live far from the fresh water source.
• So the development of water supply system using different methods started
from this places to fulfill water demands of people easily without much effort.

Water Supply System

• The system of supplying water from the source to consumers through the
networks of pipes, reservoirs and other appurtenance is known as water supply system.
Historical development
 Historical development
• Nile Civilization
River: Nile
Places: Egypt

• Indus Civilization
River: Indus
Places: China, India and Pakistan
 Historical development

• Huang He Valley Civilization

River: Huang He (Yellow River)
Place: China

• Tigris Euphrates Civilization

River: Tigris (left) Euphrates (right)
Place: Southern Iraq
 Historical development
• In the development of water resources beyond their
natural condition in rivers, lakes, and springs, the
digging of shallow wells was probably the earliest
innovation.
• As the need for water increased and tools were
developed, wells were made deeper.
• Brick-lined wells were built by city dwellers in
the Indus River basin as early as 2500 BCE, and
wells almost 500 meters (more than 1,600 feet) deep
are known to have been used in ancient China.
 Historical development
• Construction of qanats probably originated in ancient Persia about 700
BC.
• A qanats is slightly sloping tunnels driven into hillsides that contained
groundwater and convey that water downhill by gravity to nearby towns
or cities.
 Historical development
• The need to channel water supplies from distant
sources was an outcome of the growth of urban
communities.
• Among the most notable of ancient water-
conveyance systems are the aqueducts built between 312
BCE and 455 CE throughout the Roman Empire.
• Aqueducts are structures used to conduct a water
stream across a hollow or valley. In modern
engineering, however, aqueduct to a system of pipes,
ditches, canals, tunnels, and supporting structures used
to convey water from its source to its main
distribution point.
• Extending from a distant spring-fed area, a lake, or a river,
a typical Roman Aqueduct included a series of
underground and aboveground channels.
• When crossing a valley, aqueducts were supported by
arcades comprising one or more levels of massive granite
piers and impressive arches.
 Historical development
• Ancient aqueducts and pipelines were not capable of withstanding much pressure.
• Channels were constructed of cut stone, brick, rubble, or rough concrete. Pipes were
typically made of drilled stone or of hollowed wooden logs, although clay and lead
pipes were also used.
• The ancient Greek civilization of Crete (3200-1100 BC),known as the Minoan
civilization, was the first civilization to use underground clay pipes for sanitation
and water supply.
• The earliest recorded use of copper piping comes from the Egyptians who made the
first metal pipe from copper around 3000 BC.
• During theMiddle Ages there was no notable progress in the methods or materials
used to convey and distribute water.
 Historical development
• Cast iron pipes with joints capable of withstanding high pressures were not
used very much until the early 19th century.
• Asbestos cement, ductile iron, reinforced concrete, and steel came into use
as materials for water supply pipelines in the 20th century.
• Galvanized piping was commonly installed in homes built before 1960 AD.
• In 1936 – PVC pipes began to be installed for residential drinking water
distribution and wastewater pipelines (Germany).
 Historical development
Developments in water treatment
• In addition to quantity of supply, water quality is also of concern.
• Sanskrit writings from as early as 2000 BCE tell how to purify foul water by boiling
and filtering.
• But it was not until the middle of the 19th century that a direct link between polluted
water and disease (cholera) was proved, and it was not until the end of that same century
that the German bacteriologist Robert Koch proved the germ theory of disease,
establishing a scientific basis for the treatment and sanitation of drinking water.
• At the end of the 19th century and the beginning of the 20th, the main goal was
elimination of deadly water borne diseases. The treatment of public drinking water to
remove pathogenic, or disease-causing, microorganisms began about that time.
• Treatment methods included sand filtration as well as the use of chlorine for disinfection.
 Historical Development of Water Supply System(National context)
Ø Over 2000 years ago, Kirat Regime rain fed ponds and springs for collection of water.
Ø Main function of ponds was to recharge shallow aquifers during dry seasons.
Ø Later the Lichhavi King linked the pond to stone pouts and dug well to provide water
to city.
Ø First stone-pout in HadiGaon, Kathmandu built by Lichhavi King Mandev I in 550A.D
Ø Mangaldhara of Patan is oldest remaining stone spout.
Ø During the Malla Regime, the networks of canal, pond and water conduits specially made
of stone or timber or burnt clay.
Ø Quality of water was maintained using river sand, gravel, coarse sand and charcoal and
filter media.
Ø Birdhara system (1891-1893), first piped water supply system for drinking purpose
was launched in Kathmandu during the time of Rana Prime Minister Bir Sumsher, also
established Pani Goshwara Adda (The office for water supply), and provide limited
private and community standpipe in few selected part of Kathmandu.
 Historical Development of Water Supply System(National context)
Ø Water brought from pipes from Shivapuri area in the north of Kathmandu and stored in
reservoir in Maharajgunj Panipokhari.
Ø Bhim Samsher, water was brought from Shangla Khola and was stored in reservoir at
Balaju.
Ø Water used for generating hydro-electric at Pharping was used for drinking as well.
Ø From the first five year plan 1956-1961 clean drinking water was supplied.
Ø 1963, government launched water supply project at Sundarijal.
Ø Department of Water Supply and Sewerage (DWSS) was formally established in 1972.
Ø In fourth five year plan, department of drinking water and sewages was started.
Ø National water supply co-operation was established to operate, maintenance and
development of water supply system in 24 cities and town.
Ø Kathmandu Upatyaka Khanepani Limited (KUKL) was established in 2006 and took
over operation and management of water supply from NWSC from 2008.
 Historical Development of Water Supply System(National context)
Ø For region outside Kathmandu, small town water supply and sanitation project were
developed in community partnership approach which requires water and sanitation users
committee to be fully involved in major project decision
Ø In 1996 rural water supply and sanitation fund development board was established to
address the need of many small and medium sized schemes in rural areas through a system of
technical support agencies ( consultancy, NGOs, INGOs support organizations)
Ø After the coalition of WHO and DWSS, the drinking water was decentralized all over the
country.
Ø In 2011 Government of Nepal provided Sanitation and Hygiene Master Plan, a
nationwide guideline, with a target to declare ODF Nepal by 2017.
Ø July 2018, water supply coverage is reached to 87.88%, as well as sanitation coverage is
99%.
Ø Nepal achieved its one of the most important goals of being declared as an Open Defecation
Free (ODF) country in September 2019
 Objectives of water supply system
Water Supply System
• The system of supplying water from the source to consumers through the
networks of pipes, reservoirs and other appurtenance is known as water supply system.
 Objectives of water supply system
ØThe main objective of water supply system is to bring water from
source and supply safe water to the consumers in adequate quantity
efficiently at low cost.
ØBeside this, the organized water supply system has following objectives:
• To supply safe and wholesome water to the consumers
• To protect public health from various water borne diseases
• To supply water in adequate quantity to the consumers: quantity of
water should be sufficient enough to fulfill water demand of the consumers
• To make water easily available to consumers so as to encourage
personal and household cleanliness
• To develop hygienic condition in the locality
• To minimize the hardship in collecting water
• To supply water to commercial establishments, industries
• To provide enough water for fire fighting purposes.
 Impacts of Water Supply System
• Positive Impacts:
i) Saves time (long go and bring).
ii)Improves hygienic condition.
iii)Safe, reliable, adequate and effective supply is gained.
iv)Enhance tourism, industries, etc.
v)Increases socio economic activities of individuals, family and
community and so the living standard.
vi)Economic growth of whole nation.

• Negative Impacts:
i) Reduces downstream water and effects on aquatic life;
pollution increases.
ii)Decreases ground water table.
iii)Generates large quantity of waste water which is the main cause of
environmental problem.
iv)It may degrade natural beauty.
v) May create dispute between downstream water users.
Schematic diagram of typical water supply system
Ø The layout of water supply system and its component extending from the water source
to the consumer areas is called schematic diagram of a water supply system.
Ø Factors affecting water supply system
• Topography of area
• Types of water sources
• Choice of component
• System of supply
• Requirements of the consumers.

Ø Rural water supply scheme

Intake>sedimentation tank>disinfection>distribution

Ø Urban water supply scheme

Intake > reservoir > sedimentation tank > sedimentation with coagulation >
Filtration > Disinfection > hardening / softening > aeration > storage tank > distribution
Schematic diagram of typical water supply system
The essentials of water supply scheme are follows:
a. Source: It should be selected in such a way that it is reliable and having minimum
number of impurities.
b. Intake: The next step is to construct intake to collect water. Pipe line to convey water
to the treatment plant called transmission.
c. Treatment plant: For the treatment of water. The treatment process depends upon
quality at source and quality required. i.e. optional
d. Pipe line to convey water from treatment plant to the reservoir also called
transmission.
e. Clear water reservoir: to reserve the treated water. i.e. optional.
f. Distribution system: depends upon the elevation of clear water reservoir (gravity
system, pumping system or dual system) consisting of pipe networks.
 Major components of water supply system
Sources
Surface Underground Wells
•River, streams •Spring •Artesian well
•Lakes •Wells •Dug wells
•Ponds •Infiltration galleries •Tube wells Distribution
•Impounded reservoir •Infiltration well system
•Shallow
Gravity Pumping Dual
•Deep
system system system

Intake works
District water mains

Treatment works
Miscellaneous Plain Sedimentation Filtration Disinfection Branches and services pipes
treatment sedimentation with coagulation

Consumers

Wastewater
 Flow diagram on essentials of water supply engineering
Intake or
sources Treatment works
collection works

1. Surface sources: 1. Plain sedimentation

i. rivers/streams 2. Sedimentation with coagulation
ii. Lakes 3. Filtration(removes microorganisms)
iii. Impounded 4. Disinfection (kills pathogenic bacterial)
reservoirs(artificially made large 5. Miscellaneous treatment
reservoir and from where water is
available throughout the year)
 Flow diagram on essentials of water supply engineering

Reservoirs Distribution systems District water mains

1. Gravity system
2. Pumping system
3. Dual system Branch and service pipes

Users tap

Waste water engineering

Typical flow diagram on essentials of water supply engineering

Intake Treatment Plant Reservoirs

Distribution Systems

Consumers tap
Components of water supply system and their function
Intake: A device or a structure constructed at the water source for the purpose of
drawing water from the source and conveying to the other components of the water
supply system is termed as intake. It mainly comprises of screen at open end to screen
out large and floating materials, conduit to convey the water from the source, valve to
regulate the flow and housing in the form of chamber or tower.
Components of water supply system and their function
Pump: It is a device to lift the water from the source. Pumping is required when the
consumer area is at the higher elevation than the source. It should be avoided as far
as possible to minimize the cost.

Transmission main: It is a pipe laid to convey water from source to reservoir. It is

designed for the flow equivalent to the maximum daily demand. The transmission main
and all other components located in it are designed for the average flow as daily peak
factor is considered to be one in Nepal.
Components of water supply system and their function
Collection Chamber: Collection chamber is provided either at the intake or near the
intake site to collect the water from one of more sources. It breaks the incoming
water pressure into atmospheric pressure which prevents the backflow of water from
one source to another.

Distribution Chamber: It is a tank provided at the junction of the pipeline when

water has to be conveyed in more than one direction at atmospheric pressure.

Interruption Chamber: It is a tank present in the transmission main to break the

excessive internal water pressure built in the pipeline.
Components of water supply system and their function
Reservoir: It is a tank or a basin which is used to store water. It may be classified as
clean water reservoir and service reservoir. Clean water reservoir stores water after
treatment has been done and is used for water supply purposes. Service reservoir stores
water that is used for firefighting purposes.

Distribution System: Distribution system is a network of pipeline that conveys the

water from the service reservoir to the consumer. It is designed for maximum or peak
flow.

Break Pressure Chamber (BPC): It is a tank that is located in the distribution system
to break the excessive internal water pressure built up in the pipeline. It reduces the
cost as it avoids the necessity of high-pressure rating pipes. It is provided with the float
valve.
Components of water supply system and their function
Public Stand Post (PSP): It is a structure in the pipeline (usually in the rural water
supply system) from where water is distributed to the consumers.

Valves: Valves are appurtenances provided in the pipeline to control and regulate the
flow of water, to prevent the flow in opposite direction, to release the excessive pressure
and to conduct other functions.

Valve Chamber: The chamber in which one or more valves are located is called a valve
chamber.

Fittings: Fittings are those appurtenances that allow pipes to be joined or installed in the
appropriate place and closed where necessary.
Thank you