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- 1. International Journal of Civil Engineering OF CIVIL ENGINEERING AND
INTERNATIONAL JOURNAL and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 5, September – October (2013), © IAEME
TECHNOLOGY (IJCIET)
ISSN 0976 – 6308 (Print)
ISSN 0976 – 6316(Online)
Volume 4, Issue 5, September – October, pp. 181-190
© IAEME: www.iaeme.com/ijciet.asp
Journal Impact Factor (2013): 5.3277 (Calculated by GISI)
www.jifactor.com
IJCIET
©IAEME
IMPACT OF STAGING HEIGHT OF SERVICE RESERVOIR ON THE
INSTALLATION COST OF WATER SUPPLY SCHEME - A CASE STUDY
D.Jayganesh*, Dr. J.Jegan**, Dr.P.Mariappan***
*Assistant Professor, Dept. of Civil Engineering, University College of Engineering,
Ramanathapuram - 623 513,TN.
**Head, Dept. of Civil Engineering, University College of Engineering,
Ramanathapuram-623 513,TN.
***Sub Training Centre, TWAD Board, Trichy-620 023,TN.
ABSTRACT
The total cost of water supply scheme includes cost of source, pumping main, service
reservoir and distribution network system. Conventionally, optimization of pumping and distribution
system is done separately sans considering variation of the staging height of service reservoir. .An
attempt has been made, as an integrated approach, to optimise the total cost of the scheme taking into
account of the various staging height of service reservoir. Planning and design of water supply
scheme to Kamayakoundanpatty, a town panchayat, in Theni district, has been done with the above
concept as a case study. Cost of service reservoir increases with height due to lifting charge and
cantering. Cost of distribution network remains almost unchanged after certain height of service
reservoir. Economical choice of pumping main component increases with the staging height of
service reservoir in lieu of increasing duty of pump set and electrical energy consumption with the
same. The staging height is found to affect the optimum cost of pumping system and the distribution
system. It is found that 12 metres staging height gives the least cost option for the project studied.
KEY WORDS: Cost of water supply scheme, integrated approach, staging height of SR, ECP, Loop
Ver.4
INTRODUCTION
Provision of safe and protected water supply ensures public health as a preventive measure.
Great importance is paid to install protected water supply systems to public, by mostly governments,
in developing countries. Huge investments are allocated every year for the drinking water sector.
Holistic method of planning and design may yield cost effective schemes. A typical layout of water
181
- 2. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 5, September – October (2013), © IAEME
supply system, from the source to the distribution system is shown in figure 1 for a groundwater
om
system,
based –pumping scheme. More than 80 % of rural water scheme in India are groundwater dependent.
Generally, a water supply scheme accommodates a source, transmission main, may be pumping or
gravity, treatment plant if warranted service reservoir (storage) and distribution network with house
warranted,
service connections and public fountains.
Pump House
Service
Pumping
Main
Reservoir
Distribution
System
Borewell
Figure 1. Schematic diagram of a typical Water Supply Scheme with a bore well as source
The cost of any water supply system (WSS) generally includes the cost of source, pumping
he
system, conveying system. Water Treatment Plant (WTP)
(if necessary), service reservoir and
distribution system. The source accounts for nearly 10% to 15% of scheme while the conveying main
istribution
coupled with pumping system shares the cost of fairly 30% to 35%. The rest 60% to 65% of cost of
ping
the water supply scheme is shared by the service reservoir and distribution system. In practice,
ystem.
economical size selection of pumping main ( including pumping plant ), which compromises
,
c
between the pumping unit cost and cost of pipe, is done. The optimization of distribution system is
do
performed for cost effectiveness.
The impact of variation of staging height of service reservoir is seldom taken into
consideration in the process of optimization of pumping main ( conveying main ) and distribution
ss
system. Instead, a fixed height is considered. Increasing the staging height may increase the cost of
pumping main by warranting high head of pump and a higher size of pipe and decrease the cost of
and
distribution system permitting to go for lower pipe size. The vice versa is also possible. Hence, an
integrated approach was made by taking into consideration of various staging height of service
reservoir on the cost of a water supply system
pply
In order to optimize the pumping main, various application software, like LPP88, ECP are
commonly used. LPP88 is based on the principle of linear programming and ECP is a tailor made
software developed following the guidelines contained in the CPHEEO (1999) manual being used in
Tamil Nadu Water Supply and Drainage Board, India. Economical pipe size had also been chosen
using maximum and minimum technique (Mariappan, 1994). . Pannirselvam (2004) has reported
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- 3. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 5, September – October (2013), © IAEME
that transporting certain quantity of water by pumping through several sizes of pipes within the
velocity ranges of 0.6 to 1.5 m/s are suitable. The smaller diameter of pipes increases the velocity
and high frictional losses. When the diameter of pipe is larger, the cost of pump and annual cost of
pipes can be reduced. The diameter of the pipeline, which provides such optimum condition, is
known as the economic diameter of the pumping main. Further, an optimum velocity range in the
water conveying system for selecting the size of pipe has been reported as 0.8 to 1.2 m/s ( Raja
Jayachandra Bose, Neelakantan and Mariappan, 2013).
Numerous research works have been done on the optimization of distribution system with
fixed staging height (. Quindry et al., 1984 ; Bhave,1983; Chiplunkar et al,1986; Waiski,1987; Perez
et al.,1993; Brian,1994; Gupta and Bhave,1994; Walski,1995; and Savic and Walters ,1997) and
none of them studied the impact of staging height on the total cost. ; .
DESCRIPTION OF STUDY AREA
Kamaya Koundan Patty is a special panchayat located in Theni district of Tamil Nadu
situated at 3.5km west of Kambam town. It covers an area of 13 square kilometre. As per the 2001
census, population is 9220. Population growth increases to a minimum extend of 10% growth for 15
years and 20% growth for 30 years. The entire town of Kamayakoundanpatty has been divided into
3 zones for design convenience. The design and analysis of water supply distribution network has
been performed for each zone separately. It requires a potable and protected water supply scheme.
The source for the Kamayakoundanpatty water supply scheme is river Mullai Periyar. Since the
Kamayakoundanpatty town panchayat is located at the foothills of Western Ghats, a remote area, the
chance for polluting the source is very less.
METHODOLOGY
In order to assess the contours of KamayaKoundanpatty, topographical survey was done and
other details : population, length from source to SR and street length were also collected. Population
forecast was done adopting the methods: Arithmetic increase method, Incremental increase method,
Geometric increase method, Graphical method and Method of density. Demand estimation, street
wise requirement, is determined according to the norms of Central Public Health and Environmental
Engineering Organisation (CPHEEO), 1999, and Tamil Nadu Water Supply and Drainage Board
(TWAD Board), Government of Tamil Nadu..Standard schedule of rates of Public Works
Department (PWD) and TWAD Board were used for cost estimates. Economical size of pumping
main was determined by using ECP (Economic cost of pumping main) software for the staging
height of Service Reservoir (SR) from 10 m to 20 m. The cost of SRs for the various staging height
was also reckoned. The optimization of distribution system considering the effect of staging of
service reservoir was performed using the application software, LOOP 4
Loop version 4.0 is entirely a new version of the earlier program LOOP version 3.0, developed and
distributed under the joint efforts of UNDP/WORLD BANK. LOOP program can be used for the
design and simulation of new, partially or fully existing, gravity as well as pumped water distribution
system. It is capable of designing networks upto 1000 pipes and 750 nodes.
The economical total installation cost is given by
Optimum total cost (TC) = C ECP + C SR + C dist ----------------- (1)
Where TC- Optimum total cost. C ECP – Economical cost of pumping main,
service reservoir, and C dist - optimum cost of distribution system.
183
C SR – cost of
- 4. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 5, September – October (2013), © IAEME
RESULTS AND DISCUSSION
The results of topographical survey, population forecast and cost details of pumping main,
service reservoir and distribution system are presented below.
Topography .
Ground level (GL) in the distribution area of study area varies from a maximum of 395.86 m
to a minimum of 382.95 m above MSL. The contour map is shown in
figure 2. It infers that town
is undulating with a .13 m difference in GL.
Figure 2. Contour of distribution system in Kamayakoundanpatty
Design Population
The population projection made from decadal population of 1961. 1971,
1981,1991,and 2001 to the year 2031 by various methods is depicted in figure 3. Considering the
scope of expansion and growth rate, the design population obtained by the method of population
growth rate was taken ,i.e ., 12500.
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- 5. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 5, September – October (2013), © IAEME
Figure 3. Populat
Population forecast by various methods
Economical size of pumping main with staginh height of SR
The staging height of SR decides the static head in a system. The duty of pumpset, in turn,
increases with the staging height. The results of economical cost analysis for the staging height 10
metre to 20 metre of SR are plotted for easy vis
visualisation ( Figure 4). It is observed from the figure 4
that the economical cost of pumping main increases with the staging height due to increasing duty of
increases
pumpset and corresponding the electrical energy cost. The following relationship governs the
relationship between staging height and economical cost of pumping main.
CECP = -915.6x2 + 12362x + 6E+06 -------------------------------------------(2)
correlation coefficient ,R² = 0.969
Where x – staging height of SR in metre.
Economical cost of pumping main,Rs.
7800000
7600000
7400000
7200000
7000000
6800000
6600000
9
11
13
15
17
19
Staging height of SR
Figure 4. Economical cost of pumping main with staging height of SR
185
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(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 5, September – October (2013), © IAEME
Cost of SR with staging height
The cost variation of Service Reservoir with the staging height from 10 metre to 20 metre is
shown in figure 5. The cost of SR varies exponentially with staging height due to centering and lift
charges.
CSR = 4.723e0.068x
------------------------------------------------------(3)
Cost of Service Reservoir, Rs. Lakh
25.00
20.00
15.00
10.00
5.00
0.00
9
11
13
15
17
19
Staging height, m
Figure 5. Cost of SR with the Staging height
Correlation coefficient, R² = 0.981
Cost of Distribution system with staging height of SR
The results of optimal design of distribution system for the staging height of 10 to 20 m of
SR are depicted in figure 6. The correlation coefficient for relationship between the optimum cost of
distribution system and staging height of SR is
nearly 1. It shows very good relationship.
C dist = -0.004x5 + 0.337x4 - 10.51x3 + 162.2x2 - 1239.x + 3748.-------(4)
Correlation coefficient, R² = 0.977
Where x is the staging height of SR
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(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 5, September – October (2013), © IAEME
16
Cost of Distribution System, Rs. Lakh
14
12
10
8
6
4
2
0
9
10
11
12
13
14
15
Staging height, m
Figure 5. Optimum Cost of Distribution system with staging height of SR
It is noticed from the figure five that a staging height beyond certain value does not influence
the optimum size of distribution system. It may be due to the reason that a minimum pipe size, 100
mm, has been stipulated in the CPHEEO manual for the distribution system. Hence, static head
available shall be used to go for lower pipe size. But the staging height 10 and 11, with the pressure
head, warrant higher pipe size to ensure minimum residual pressure, 7 metre for singly storey
building area and 12 metre for double storey house are, in the distribution system. The frictional loss
which can be permitted is the main concern in the cases of lower staging height.
Total Cost
The optimum cost of pumping main, distribution system and cost of SR for the various
staging height of SR are presented in table 1 and figure 6. Figure 7 gives the summary of the cost of
the components with the grand total.
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(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 5, September – October (2013), © IAEME
SI.
No
1
2
3
4
5
6
7
8
9
10
11
Table 1. Cost of various components with staging height of SR
Staging
Service
Optimum cost of Optimum cost
Total cost
Height in
Reservoir
distribution
of pumping
in Rs
metre
cost in Rs
system in Rs
main in Rs
10
1000000
1375940
6792678
9168618
11
1025000
395089
6852678
8272767
12
1050000
283000
6912678
8545678
13
1100000
283000
6979767
8345678
14
1200000
283000
7045980
8528980
15
1300000
283000
7324862
8907862
16
1400000
283000
7391705
9224705
17
1550000
283000
7458549
9291549
18
1625000
283000
7557695
9465695
19
1765000
283000
7607268
9655268
20
1910000
283000
7656841
9849841
The table 1 infers that an integrated approach is necessary to arrive at the lowest cost of a water
supply scheme with pumping system. Staging height is the main cost controlling factor. The method
of analysing the optimum cost of pumping main and distribution system separately without taking
into consideration of staging height may not yield true least cost option. The total Cost for 12 m
staging height of SR is found to be the least for the Kamayagoundanpatty water supply scheme. The
relationship between the staging height of SR and the total cost is shown in the equation 5.
TC = 0.016x4 - 1.087x3 + 26.28x2 - 276.8x + 1151------------------(5).
Total Installation Cost, Rs. Lakh
Correlation coefficient,R² = 0.991
100.00
98.00
96.00
94.00
92.00
90.00
88.00
86.00
84.00
82.00
80.00
9
11
13
15
17
Staging height, m
Figure 6. Staging height of SR with total cost
188
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(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 5, September – October (2013), © IAEME
12000000
10000000
Cost,Rs
8000000
6000000
4000000
2000000
0
9
11
13
15
17
19
21
Staging height of Service Reservoir
SR
D'System
Pumping main
Total cost
Figure 7. Cost of various components with Staging height of SR
CONCLUSION
The present study suggests an integrated approach to get the least cost system. The staging
height of SR is an important factor which has influence the cost of pumping unit,, size of pumping
main and distribution network. An integrated approach helps to optimise the overall scheme
installation cost. A compromising staging height, which results in economical pumping cost and
least cost distribution network, may be decided. In the case of Kamayagoundanpatty water supply
scheme, the least cost occurs at the staging height of 12 metre. Depending upon the topography and
scheme capacity, the optimum staging height may vary. The present study suggests the planners,
design and field to follow the above concept for economical system.
REFERENCES
1.
2.
3.
4.
CPHEEO, 1999, Manual on Water Supply and Treatment, Central Public Health and
Environmental Engineering Organization, Ministry of Urban Development, Government of
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Mariappan, P, et al, 2011, Validation of Design principles of Multi village water supply
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Raja Jeya Chandra Bose, Neelakantan,T.R, Mariappan, P, et al, 2013, Modified design
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