INTERNATIONAL JOURNAL OF PURE AND APPLIED … COEAT.30.pdf · WaterGEMS software gives optimal...

Research Article Impact Factor: 4.226 ISSN: 2319-507X Sajedkhan S. Pathan, IJPRET, 2015; Volume 3 (8): 308-319 IJPRET

Organized by C.O.E.T, Akola & IWWA, Amravati Center. Available Online at www.ijpret.com

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INTERNATIONAL JOURNAL OF PURE AND APPLIED RESEARCH IN ENGINEERING AND

TECHNOLOGY A PATH FOR HORIZING YOUR INNOVATIVE WORK

SPECIAL ISSUE FOR NATIONAL LEVEL CONFERENCE

"SUSTAINABLE TECHNOLOGIES IN CIVIL ENGINEERING"

OPTIMAL DESIGN OF WATER DISTRIBUTION NETWORK BY USING WATERGEMS

SAJEDKHAN S. PATHAN1, DR. U. J. KAHALEKAR2 1. PG Student, Department of Civil Engineering, Government College of Engineering, Aurangabad (M.S.) India.

2. Professor and Head, Department of Civil Engineering, Government College of Engineering, Aurangabad (M.S.) India.

Accepted Date: 13/03/2015; Published Date: 01/04/2015

Abstract – Water distribution network systems are designed to deliver water from a source in the adequate quantity, quality and at

satisfactory pressure to all individual consumers. Water distribution network are designed with an objective of minimizing the overall cost while meeting the water demand requirements at adequate pressures. The system is a pipeline network consisting of one source node and several demand nodes is considered to find its optimal geometrical layout which delivers known demands from source to consumers over a long period of time. In this paper design of water supply network duly considering optimization in addition to the cost minimization and minimum head requirement is presented. Gradient method is one in which the pipe discharges and nodal heads are taken as the basic unknowns in formulating the Q-H equations. The Q-H equations for the pipe head loss relationship are non linear. These equations are linearised by an expansion using Taylor’s series and solved by Gradient method. Water GEMS software algorithm is based on Gradient method gives optimal solution for the design of new as well as expansion of existing water distribution network. The primary variables are flow in the network while other decision variables includes design parameters i.e. pipe diameter, reservoir elevations etc. Head and velocity dependent analysis is used to determine the actual supply form each node to consumers. In this paper CIDCO N-8 a part of Aurangabad city is designed by Water GEMS software. Keywords- WaterGEMS Software, Water distribution network, Gradient method, Optimization

Corresponding Author: MR. SAJEDKHAN S. PATHAN

Co Author: DR. U. J. KAHALEKAR

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INTRODUCTION

A water distribution network is an essential hydraulic infrastructure which is a part of the water

supply system composed of a different set of pipes, hydraulic devices and storage reservoirs.

Water distribution network connects consumers to sources of water using hydraulic

components. Water distribution system infrastructure is a major component part of a water

utility. A good distribution network system is essential to improve the efficiency of water

supply. Water distribution network systems are designed to deliver water from a source in the

adequate quantity, quality and at satisfactory pressure to all individual consumers. A

distribution network may have different configurations depending upon the layout of the

existing area. Generally, water distribution network have a branched and looped type of

configuration of pipelines. A network is said to be an optimal network in which layout is not

fixed priori but it is allowed to vary in order to obtain the optimal solution. The task to be

performed in this context involves resolution of two problems which are layout and design.

The system is a pipeline network consisting of one source node and several demand nodes is

considered to find its optimal geometrical layout which delivers known demands from source to

consumers over a long period of time. Head and velocity dependent analysis is used to

determine the actual supply form each node to consumers. The primary variable is flow in the

network. The constraints are that demands are to be met and pressures at selected nodes in

the network are to be within specified limits. The decision variables thus consists of design

parameters i.e. pipe diameters, reservoir capacity, and elevation. It is also important to look

over cost considerations during the design and analysis of a system while carrying out synthesis

of a water supply system. Designing of water distribution network to satisfy functional

requirements is not enough as the solution must also be based on least-cost considerations.

Several researchers have worked on this design optimization. A large amount of literature exists

on optimization of water distribution network design. Over the past some decades, many

models have been developed for the analysis and optimal design of water distribution network

(e.g. Vasan, A. and Simonovic, S. P. (2010), Shie-Yui Liong and Md. Atiquzzaman (2004), Cunha,

M. and Sousa, J. (1999)). Various investigators have proposed the use of mathematical

programming techniques such as Linear programming gradient, Linear programming, Non linear

programming, Dynamic programming (e.g. Varma, et. al. (1997), Modak, P. M. and Rabbani, W.

I. (1983), Bhave, P. R. (1983),). Most recently, due to development in the field of computer,

researchers are designing water distribution network using computer programmed various

software’s or Toolkit based on different analysis methods such as Gradient method, Hardy-



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Cross method, Newton-Raphson method (e.g. Dabhade, P. D. (2012), Vasan, A. and Simonovic,

P. (2010)).

WaterGEMS software is developed for design and analysis of water supply network. The

software is also used for expansion of existing water distribution network. The software provide

required standard and economical environment for design, analysis and troubleshooting of new

and existing supply network with minimum time duration. WaterGEMS software algorithm is

based on Gradient method. WaterGEMS software gives optimal solution irrespective of type of

network i.e. network may be branched network, looped network or combination of branched

and looped network. In other words, WaterGEMS software gives solution of any simple or

complex network. The key feature of WaterGEMS software is that, it can be used to accurately

simulate network before it has been built or modified. Since WaterGEMS is computer based

software, while simulation of network it can easily identify potential problems and nullify them

within interactive environment so that expensive error can be avoided.

In this present paper an algorithm based on Gradient method is used to determine the least-

cost i.e. optimal design of water distribution network. The proposed method is illustrated

through a design example in an accompanying paper dealing with application. Design of water

distribution network duly considering optimization in addition to the cost minimization and

minimum head requirement is presented. In this paper CIDCO N-8 a part of Aurangabad city

water distribution network is designed by WaterGEMS software.

Objectives

Water distribution network are designed with an objective of minimizing the overall cost of

network while meeting the water demand requirements at adequate pressures for specified

maximum design discharge and also to provide possible minimum length of network whose

operation and maintenance should be low and economical.

System Development

WaterGEMS software algorithm is based on Gradient method gives optimal solution for the

design of new as well as expansion of existing water distribution network. The software firstly

creates the network and by use of Model Builder transfers existing data on network. Next step

is applying elevation data with Trex then takes the demand using Load Builder and as an output

it generates various scenarios and alternatives and lastly goes for simulation of network for

giving optimal design of water distribution network.

Description of the Network Solution Algorithm used by WaterGEMS



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The unknown pipe flows, Qx, x = 1,…, X, and unknown nodal heads, Hj, j = 2,…,J are taken as the

basic unknown parameters in formulating the Q-H equations.

General formulation. Applying the pipe-head loss relationship for all pipes,

Hi – Hj = Rox Qn

x , x = 1,….., X

The Q-H equations are formulated for single and multiple source networks with known pipe

resistances. The Q-H equations for the pipe head loss relationship are nonlinear. These

nonlinear equations are linearised by an expansion using Taylor’s series and neglecting the

residue after two terms. Thus, the nonlinear pipe-head loss equations for the tth iteration are

written as

(tHoi + tΔHi) - (tHoj + tΔHj) = Rox tQn

ox + n Rox |tQox|n-1 tΔQx, x = 1, ……,X Eqn 1

In which Rox = known resistance constant of pipe x; tHoi and tHoj = assumed or known nodal

heads for the tth iteration at nodes i and j, respectively; tQox = assumed or known discharge in

pipe x for the tth iteration; and tΔHi, tΔHj and tΔQx = the unknown corrections for the tth

iteration. No correction is necessary for the nodal head if it is fixed. Rewriting Eqn 1 by

transferring fixed nodal head terms, if any, on the right hand side and the term containing ΔQx

on the left hand side

t+1Hi – t+1Hj – n Rox |tQox|n-1

tΔQx = Rox tQn

ox, x = 1, ….,X Eqn 2

in which t+1Hi and t+1Hj = corrected nodal heads after the tth iteration at nodes i and j,

respectively. Subtracting n Rox tQn

oxfrom both sides

t+1Hi – t+1Hj – n Rox |tQox|n-1(tQox + tΔQx) = (1-n)Rox tQnox, x = 1, ….,X Eqn 3

Replacing tQox + tΔQx by t+1Qx

t+1Hi – t+1Hj – (n Rox |tQox|n-1) t+1Qx = (1-n)Rox tQ

nox, x = 1, ….,X Eqn 4

Eqn 4 provides X number of linearised equations involving corrected values of pipe discharges

and nodal heads as unknowns.

Node-flow continuity equations are linear and can be written for corrected discharge value as

+1Qx + qo j = 0, j = M + 1,…., M + N Eqn 5



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Which are N linear equations, Simultaneous solution of Eqn 4 and 5 provides the corrected

values of X pipe discharges and N unknown nodal heads.

Pipe discharge tQox can be taken as unity for the first iteration, or can be alternatively taken as

some other arbitrarily chosen value.

For calculating head loss uses Hazen Williams’s formula,

V = 0.85CH R0.63 S0.64

Where,

CH = The dimensionless Hazen Williams Coefficient R = Hydraulic radius of the pipe in m

S = ratio of energy loss per length of pipe(m of fluid/m) V = Flow velocity through pipe in m/sec

RESULTS AND ANALYSIS

Present Water Supply Scenario: The method is illustrated with an example to study the various

design constraints. Aurangabad City is situated in central part of Maharashtra State. However,

for optimal design purpose a part of water supply network of CIDCO N-8 area from Aurangabad

city is considered. Longitude and Latitude of study area are 190 531 N and 750 231 E respectively.

The source for the study area is in the form of ESR which is located at CIDCO N-8, Aurangabad

with an average ground level of 592.4 m with a fixed capacity. In the city pipes are laid of

various materials such as R.C.C., C.I., and A/C for the distribution system and for feeding

ESR/GSR. Most part of city is covered by distribution network.

Data collection:

Location and capacity of ESR

Existing water supply network information

Controlling levels of ESR

Reduced levels of all components in distribution network



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Table 1: Daily Water Demand

Sr.No.

Particulars

Present Stage (Year 2015)

Immediate Stage (Year 2030)

Ultimate Stage (Year 2045)

Population

Rate of lpcd

Qty in MLD

Population

Rate of lpcd

Qty in MLD

Population

Rate of lpcd

Qty in MLD

1 Domestic Demand 7296 135 0.9850 12604 135 1.7015 22645 135 3.0571

2 Institutional Demand 0.1477 0.2552 0.4585 3 Public Use Demand 0.0985 0.1701 0.3057 4 Total Net Demand 1.2312 2.1268 3.8213

5 Total Gross Demand with 15% Losses

1.4485 2.5021 4.4956

6 Max.Design Demand (2.7 x Total Gross)

3.9109 6.7557 12.1382

Institutional Demand is assumed as 15%, Public Use Demand as 10%. Therefore, total per

capita demand calculated as equal to 200 lpcd.

Table 2: Overall cost comparison of three scenario

DI Pipe (Class K-7) HDPE Pipe CI Pipe (Class LA)

Dia

mm

Leng-th

(m)

Unit

cost

(Rs.)

Cost

(Rs.)

Dia

mm

Leng-th

(m)

Unit

cost

(Rs.)

Cost

(Rs.)

Dia

mm

Leng-th

(m)

Unit cost

(Rs.)

Cost

(Rs.)

100 6977.42 794 5540073/- 101.2 6909 266 1837794/- 100 6277 1098 6892146/-

150 682.477 1171 799180/- 115.0 333 363 120879/- 150 990 1783 1765170/-

200 169.599 1488 252363/- 128.8 56 457 25592/- 200 373 2568 957864/-

250 195.462 1979 386819/- 147.1 177 592 104784/- 250 383 3461 1325563/-

300 231.215 2465 569945/- 165.6 199 746 148454/- 300 92 4465 410780/-

350 87.955 3046 267911/- 183.9 344 873 300312/- 350 216 5358 1157328/-

400 22.696 3580 81252/- 257.5 281 1383 388623/- 400 195 6061 1181895/-

- - 289.6 93 1734 161262/- - -

- - 361.8 156 2197 342732/- - -

Total

cost

78,97543/- Total

cost

34,30432/- Total

cost

1,36,90746/-



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Figure 1: Schematic diagram of a real network Figure 2: Schematic diagram of a real network

showing all Nodes showing all Pipe section

Figure 3: Optimal layout of network with Node data for DI pipe



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Figure 4: Optimal layout of network with Pipe section data for DI pipe

Figure 5: Optimal layout of network with Node data for HDPE pipe



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Figure 6: Optimal layout of network with Pipe section data for HDPE pipe

Figure 7: Optimal layout of network with Node data for CI pipe



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Figure 8: Optimal layout of network with Pipe section data for CI pipe

CONCLUSION

With the help of WaterGEMS software an optimal water distribution network are designed and

also helps in achieving objective of minimizing the overall cost while meeting the water demand

requirements at adequate pressures for specified maximum design discharge over a long period

of time. In this paper

In this paper WaterGEMS software is used for obtaining optimal design of water distribution

network of a part of Aurangabad city. The software has given three alternative optimal design

solution considering design constraints i.e. diameters, roughness coefficient, and cost based on

head and velocity dependent analysis. Considering durability, life span of pipe and operation

and maintenance point of view an optimal layout network of DI pipe is looking as more precise

network compared to other two networks. Though cost of HDPE pipe network is less but its

jointing, fitting and other expenses are more compared to DI pipe network.

The software provide required standard and economical environment for design, analysis and

troubleshooting of new and existing supply network with minimum time duration. With of



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WaterGEMS software we can identify and solve all types of problems in new as well as existing

network. The software is also used for expansion of existing water distribution network.

ACKNOWLEDGEMENT

The authors wish to express sincere thanks to their family members, colleagues and to all who

directly or indirectly helped in the work.

REFERENCES

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10. Chandapillai, J., “Design of Water Distribution Network for Equitable Supply”, Journal of

Water Resources Planning and of Management, Vol. 26, Springer, 2012, pp. 391-406.



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11. Lansey, K. E., Duan, N., Mays, L. W., and Tung, Y. K., “Water Distribution System Design

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