ELEMENTS OF WATER SUPPLY NETWORK SYSTEM

1.0 Introduction.

Water supply system in urban area should be developed in a proper way to

meet the demand and at the same time, quality of water should also be maintained

with in standard prescribed limits. Thus the quality of water and the distributions are

the important issues for urban water supply system. Provision of an adequate

quantity of water has been a matter of concern since the beginning of civilization.

Even in ancient cities, local supplies were often inadequate and aqueducts were built

to convey water from distant sources

Services and network for the health, safety and convenience of the urban

population advanced further in the last century. The rich developed countries and the

poor developing countries showed distinct paths of progress in finding solutions to

these concerns. The state of the art on these concerns may be broadly defined

under a subject title “networks and services”. Networks and services can be studied

with respect to region, block district and state as well as for a town and a village; the

coverage of the topics under urban networks and services are vast. It includes water

supply, sanitation, drainage, solid waste disposal, fire services, telecommunication,

health care and educational system. The level of public utilities and services in any city

reflects its quality and governance. The public utilities and services growth in any city

has generally kept pace with the population growth.

The primary objective of water supply system is to take water from the best

available source and to subject it to processing which will ensure water of good

quality, free from unpleasant taste or odour and containing nothing which might be

determined to health, and to distribute it top meet the requirement of the town or the

city.

Any public water supply scheme should meet the following requirements:

Ensured quality of water supply for its intended use like drinking or

industrial use.

Ensured sufficient quantity of supply.

Ensured convenient and easy accessibility of water supply distribution.

Ensured economic and financial viability of water supply product such

that the capital and recurring cost falls with in the affordable limits of the

consumers of the system.

2ND SEM, M-TECH(PLANNING),YEAR-2008-09 1


2.0 SOURCES OF WATER.

The main source of water is river ‘Tapti’. The head works for the water supply

are located at ‘Nana Varachchha’. The water is being obtained from river Tapti, by

three different methods in the following manner:

1. Through the infiltration wells located at the river – bed.

2. Through tube – wells at ‘Varachchha’.

3. Through the surface purification plant by the treatment of raw water.

2.1 Surface Source:

Surface water is water in a river, lake or fresh water

wetland. Surface water is naturally replenished by

precipitation and naturally lost through discharge to the

oceans, evaporation and sub-surface seepage.

There are two major water works on the tanks on

the river tapi (N-E Corner of the city).the water released from the Ukai dam.100 Km

upstream is drawn at varachha, and sarthana water works for treatments

2.2 Ground Water:

Sub-Surface water, or groundwater, is

fresh water located in the pore space of soil

and rocks. It is also water that is flowing

within aquifers below the water table.

Sometimes it is useful to make a distinction

between sub-surface water that is closely

associated with surface water and deep sub-surface water in an aquifer

Due to the seasonal character of river tapi, ground water exploitation through

French wells infiltration wells as well as tube wells take place even at the two water

works. Of the total area about 55.60 Sq.Km. areas, which was added to the city in

1986, is not covered by a rectangular distribution network. In these areas SMC

operates about 50 bore wells, serving a population of approximately 65,000 persons.

Water from the bore wells is pumped into overhead tanks, which are connected to

stand pots. In some cases water is directly pumped into stand pots.


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3.0 FACTORS AFFACTING WATER DEMAND AND QUANTITY OF URBAN

WATER SUPPLY.

a) Factors affecting the quantity of water supply are:

Pollution and their characteristics

Climatic conditions

Size and type of city

Standard of living

Quality of water

Pressure in the supply

System of supply

Rates of water

Type of sewerage system

Metering

Fire fighting requirement

Number and type of industries

Area under public gardens

Policy regarding the metered supply

Potential sources of water supply

Age of community

b) Design period: For water supply projects, a 30 years design period is

assumed. Population forecast for this period take into consideration the

potential of various sectors of urban economy and regional physical and

economic linkages.

c) Per capita rate of water supply: The following per capita rates have been

recommended as the minimum requirement for the design of public water

supply in India:

For design population up to 5,000 → 90 lpcd per person

For design population up to 5,000 to 20,000 → 110 lpcd per person

For design population up to 20,000 to 50,000 → 125 lpcd per person

For design population above 50,000 to 2, 00,000 → 200 lpcd per person.

d) Rate of water supply: The consumption of water during the year is not always

at a constant rate. There will be seasonal, monthly, daily, and hourly variation.

e) Peak factor: The distribution system shall be design to satisfy the peak

demand of the population. The recommended peak factors for India are:



City size (Population) Peak factor

Up to 50,000 3 Times the average rate

50,000 to 2, 00,000 2.5 Times

2, 00,000 and above 2 Times

f) Water meters: the policy whether meters will be installed is a critical decision.

This involves expenditure on salary of municipal employees who read meters,

as well as revenue from consumers and some control on water use.

4.0 QUALITY OF WATER.

The following are the important parameters:

b) Temperature: the drinking water should be cool. Desirable is bet. 10c to 15.6

c.

c) Turbidity: turbidity is on account of suspended and colloidal inorganic matter

such as silt, clay and mud particle. It should be between 2.5 -10 ppm.

d) Odour and Taste: substance that produce and odour will almost invariably

impart a taste as well as odour in drinking water may be due to the presence

of microscopic organic matter or inorganic substance such as iron, sodium

carbonates and sulphates.

e) Colour: for drinking purpose the colour of water should be preferably be less

than 10ppm.

f) Alkalinity: alkalinity is mainly because of carbonates, bicarbonates and

hydroxides. It helps in the process of coagulation while purifying the water.

g) Hardness: hardness of water is due to the presence of bicarbonates

sulphates and chlorides of calcium carbonate.hardness of water should be

between 75-115 ppm for domestic purpose.

h) pH value: pH value is a symbol of presence of positive hydrogen iron

concentration in a sample of water. Water containing alkali will have OH ions,

while water containing an acid will have more H+ ions. The ph value of water

for domestic use shall be from 6.5 to 8.

5.0 DISTRIBUTION OF WATER-SUPPLY.



Distribution of water is very much important in any water supply network.

Water supply distribution is designed to satisfy the demand placed by different

land use densities and fire fighting requirements all the time. Piping systems,

pumping stations, storage facilities fire hydrants, house connections, water

meters constitute the entire distribution system. The distribution system

normally costs 60 to 70% of the total cost.

Municipal water supply system consists of the following units:

Collection works

Transmission works

Purification works

Distribution works

5.1 Distribution system characteristics

The configuration

The configuration of the system is dictated primarily by the street pattern,

topography, degree and type of development of the area and location of treatment

and storage work.

Topography and distribution

If there is a change in topography, the distribution system is divided into zones. This

will preclude extreme high pressure at lower area and maintain reasonable pressure

at higher elevation.

Grid and branching system:

The distribution system may be generally classified as grid system, branching

system or some other combination.

Pipe specification:

Distribution pipes shall not be less than 150 mm in diameter in the Indian

metropolitan cities to meet fire-fighting requirements. In other urban areas the

minimum pipe diameter shall be 100 mm.

Pressure specification

The minimum residual pressure at the time of two store houses,17 meters for three

store house and 22 mt for four store houses.



5.2 Distribution system

The spatial distribution of water consumption can be estimated by studying

population demand and commercial and industrial water use patterns. Predicted

hydrograph for each zone is required for assessing the combined peak, flow

requirement. There are four principal methods of laying out distribution system:

1. Dead-End System or Tree System:- In this system, one main pipelines runs

through the center of the populated area and sub mains take off from this to both the

sides. It is suitable for towns that have one several road and by lanes without

regularity. The main is a larger diameter at the beginning and it becomes smaller as

it goes further from the sources of water supply. The pipe, which connects house

within main pipe in the streets, is known as services pipe having 100 to 200 mm or

even 300 mm dia. Here less numbers of valves are required, but if there is case of

repairs to any sections, the supply of the branch has to be cut off giving

inconvenience to the majority. The discharge available for fire fighting in the streets

will be limited.

2. Grid – Iron System or Reticulation System:-If the dead ends of the precious

system are inter-connected, water can be made to circulate continuously through the

whole of the distribution system. This system is therefore also known as the

interlaced system. Here, the main supply pipe runs through the center of the

rectangular area and sub mains take off from these in perpendicular directions. This

system is ideal for cities laid out on rectangular plan. There is free circulation of

water, without any stagnation. In case of repairs, only very small area of distribution

system is affected, but here large numbers of cut off required. The systems require

longer pipes lengths and bigger diameters. The cost of laying water pipe is more.

3. Circular System or Ring System:- This system is most suitable for the town or

area having well planned streets and roads. In this system, the supply main forms a

ring around the distribution district. In case of fire, a large quantity of water is

available.

4. Radial System:- This system is just the reverse of the circular system. In this

system, whole area is divided in to a number of distribution districts. Each district has

a centrally located distribution reservoir from where distribution pipes run radially

towards the periphery of the distribution district. This system gives quick service,

without much loss of head.



5.3 Water treatment processes:

The purpose of water treatment is to remove all those impurities, which are

objectionable, either form taste or odour point of view or from public health point of

view.

Following are purposes of water treatment:

1. To remove colour, dissolved gas and murkiness of water.

2. To remove objectionable tastes and odour.

3. To remove the disease-producing micro-organisms so that water is safe for

drinking purposes.

4. To remove hardness of water.

For surface waters, following treatment processes are generally adopted.

1. Screening

2. Aeration

3. Sedimentation With or Without Coagulants.

4. Filtration

5. Disinfections

6. Miscellaneous Processes



Fig. Schematic layout of water treatment plant.



5.4 Norms of water supply:-

The recommended norms for per capita supply, treatment capacity, distribution and

proportion of supply, have been wondered for estimating the total requirements while

the unit costs and O & M expenditure has been used to asses the financial situation

and requirements for the future.

Table: Norms for water supply network

Sr. No. Category Avg. Min. Max.

1 Water Supply (lpcd) 150 135 180

2 Distribution network coverage (%) 77 74 79

3 Total storage required (%) 30 25 40

4 Storage capacity ratio 90 42 199

5 Total treatment req. (%) 80 75 100

6 Population dependent on House Service Connection 590 36 78

7 Person per stand post/Hand Pump 127 54 227

The present supply by SMC is an average is 85 lpcd; but these do not meet the

standard, as can be shown in the table below:



6.0 PRESENT SCENARIO OF WATER SUPPLY SYSTEM IN SURAT CITY.


Institutions/ committees Levels

Ministry of urban affairs &employment

CPHEEO

150 lpcd

150-200 lpcd

Eight five year plan

TCPO

125 lpcd

180 lpcd


The Surat city is second largest city of Gujarat and is one of the fast

developing cities. Surat Municipal Corporation has the responsibility of supplying

water to the residents of the city. Presently SMC is serving 92% of the total area

90% of the population.

The city has a well established water supply and distribution system in the

walled town, but the distribution system in the extended areas beyond the walled

town was extended on adhoc basis as and when new areas were added and the

population spread increased. Therefore, the corporation had taken up a



comprehensive programme estimated to the cost of Rs. 1026 lacs to improve the

distribution system of the city including the extended area. The scheme was

designed keeping in mind the anticipated population of the year 2001. The main line

was designed for 30 years. The water supply scheme is designed to give 275 liters

of water per capita per day.

Present Yield of Water Works:

Water Works Present Yield (in MLD)

(1) Varachha Water Works 30

(2) Sarthana Water Works 280

(3) Katargam Water Works 220

(4) Rander Water Works 150

Total Present Yield 680

Present status of Water Supply: (May 2008)

Description Old Area New Area.

Area of City112.27

Sq.Km

334.27

Sq.Km.

Total population (As per 2001 census) 24.34 Lacs 28.77 Lacs

Area covered by piped water supply (in %) 95 % 38 %

Population coverage of piped water supply (in %) 97 % *

Total water supply installed capacity 828 MLD *

Total average water supplied at present 680 MLD *

Per Capita Water Supply in lpcd (Net after losses &

industrial supply)148 Lpcd *

Total Length of Pipelines (75 to 900 mm) 2550 Km. *

Total Nos. of Water Connections: (All size) 3,27,000 *

* At present, water supply in the extended parts of the city is being catered as per

their existing water supply systems and not from SMC water works. After the



implementation of new water supply Master Plan, new area will be covered under

water supply network.

Present Storage Capacity

Storage Capacity in Lac Liters at Water Distribution Stations

Sr.No. Location Nos of UGSR UGSR Cap. ESR Cap. TOTAL Cap.

1 Khatodara 3 450.0 22.5 472.5

2 Umarwada 3 337.5 22.5 360.0

3 Katargam 3 450.0 22.5 472.5

4 Althan 2 225.0 -- 225.0

5 Athwa 1 2 315.0 -- 315.0

6 Udhna 3 335.0 -- 335.0

7 Dumbhal 1 3 297.0 -- 297.0

8 Pandesara 3 450.0 15 465.0

9 Joganinagar 1 2 450.0 -- 450.0

10 Udhna Sangh 1 140.0 -- 140.0

SUB-TOTAL (A) 25 3449.50 82.5 3532.0

Storage Capacity in Lac Liters at Water Works

1 Varachha 3 295.0 37.5 332.5

2 Sarthana 3 562.5 -- 562.5

3 Katargam 3 675.0 -- 675.0

4 Rander 2 435.0 -- 435.0

SUB-TOTAL (B) 11 1967.5 37.5 2005.0

Total Storage Capacity in Lac Liters

GRAND TOTAL (A+B) 36 5417.0 120 5537.0

NOTE:

* Not including Work of ESR of 22.5 Lac Liters capacity in progress

Alternative supply methods

Water is also supplied from umarwada station by tankers of 1000 liters each.the

supply details are as below:

Alternative supply details



Mode of supply

No. of trips

Quantity of water supplied

Period of supply

Mains areas supplied to

Tankers

140

1.40 MLD

All Season

Udhana, Umra, Piplod, Pandessara & Khatodra

7.0 PERSPECTIVE PLANNING FOR IMPLEMENTATION OF THE PROJECTS.

To meet the demands of the growing population SMC has been the

implementation a water supply project, which is divided into two phases: phase – I

is from 2001-2011 and phase-II from 2011-2021. the demand of water will be 820

MLD by 2021 as per the projection. Some works have been taken up on a priority

basis, in order to provide immediate relief (by 2001) to certain areas, at a restricted

cost.

Head/Year Priority phase Phase – I Phase-II

2001 2011 2021

Population (Lacs) 26 35 43

Water Demand (mld) @190

lpcd

490 660 820

Storage capacity (ml) 160 330 328

A separate treatment plant for the other areas could be located at Sarthana

and Katargam there will be 80% satisfaction of demand in 2001 and 100%

satisfaction in year 2011.

In order to augment supplies, a weir has been constructed on Tapi River, near

Singanpore. The purpose of weir is to increase the surface water availability. The

impoundage caused by the weir may result in an increase in the yield of French wells

at Sarthana and infiltration wells at Varachha by about 50 MLD. Two additional

surface water treatment plants of 50 MLD are under construction at Varachaha. It is

proposed to augment the supply by 60 MLD at Rander giving a total supply of about

320 to 370 MLD in the priority phase. The present storage capacity will be upgraded

from 91 MLD to 328 MLD by end of phase II in 2021.

The city has been divided into 6 water zones. North, west, central, east,s outh

and south west .in order to meet the requirements of the year 2011-21 additional



distribution stations are proposed at Singanpor , Ved.Rander, Jahangirpur,

Jahngirabad, Limbayat, Athwa, Aithan, Sagarampura, Udhana and Bhestan.

Following is an abstract of the zone wise. Water demand for the three phases

Zone Demand (MLD)

2001 2011 2021

West 79 131 180

S-W 64 118 167

North 107 162 239

Central 137 151 165

South 138 195 240

East 145 183 219

670 940 1210

A new source at katargam by construct the surface purification plant of 240

MLD capacity has been developed and it will be commissioned shortly.furthe the top

priority works like athwa water supply system with Booster Station Rander –Adajan

water supply system with Booster Station and udhana-pandesara water supply

system have also been recently completed.

The SMC intends to seek financial assistance from the World Bank or any

other Financial Institutional for implementing the water supply project to alleviate

water shortage and cater the remaining areas of the city.

Benefits:

The proposed water supply project will ensure safe potable water to the

uncovered areas within the city limit. The 4.34 million projected population of the

year 2021 is proposed to be covered there by replacing conventional methods.

Due to strengthen the system, even the existing consumers in old city will get water

with adequate pressure. People in new areas (most of the slum-dwellers) will also

get safe drinking water at their doorstep. Resultantly, people will stop using water

from unsafe sources. Due to availability of ample water supply, people will be

induced to grow more trees, resulting in overall healthy environment and this will also

stop storing and wastage of water.

8.0 CONCLUSION:



Today urban population is increasing at a rapid rate and so at the same time

the demand of water also increasing. Many cities are not able to meet the demand

and sometimes to meet the demand they are not able to keep control over the quality

of water. Thus to maintain good quality of water, with high supply efficiency,

collective action is required to meet this challenges. Contribution of urban inhabitants

is required to meet the capital and reaming expenditure for water supply system and

large capital requirement.



9.0 REFRENCES

Books:

Punamia B.C. and Jain Ashok K., “Water Supply Engineering”, (1999), Laxmi

Publications PVT.LTD, New Delhi.

B.S. Raju ,”Water supply and Waste water engineering”, (2001),Tata

Macgraw-Hill Publishing CO. LTD, New Delhi.

Deswal S.S. and Deswal S.,” Environmental Engineering”, (2001), Dhanpatrai

And CO. PVT. LTD., Delhi.

Sharma B.K. and Kaur H.,” Environmental Chemistry”, (1995), GOEL

Publishing House, Meerut.

Gohil M.B.,Popat A.K. and Gohil D.P.,” Essential Of Environmental

Engineering”,(2004) Atul Prakashan,Ahemedabad.

Web Sites:

http://www.suratmuniciple.org.

http://www.envfor.nic.in

http://www.neeri.nic.in/


http://www.envfor.nic.in/

water supply network

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