INTERNATIONAL JOURNAL OF PURE AND APPLIED RESEARCH IN ENGINEERING AND TECHNOLOGY

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1 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. PATHAN 1, DR. U. J. KAHALEKAR 2 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 Access Online On: How to Cite This Article: PAPER-QR CODE 308

2 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- 309

3 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 leastcost 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 310

4 The unknown pipe flows, Q x, x = 1,, X, and unknown nodal heads, H j, 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, H i H j = R ox Q n 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 t th iteration are written as ( t H oi + t ΔH i ) - ( t H oj + tδh j ) = R ox t Q n ox + n R ox t Q ox n-1 tδq x, x = 1,,X Eqn 1 In which R ox = known resistance constant of pipe x; t H oi and t H oj = assumed or known nodal heads for the t th iteration at nodes i and j, respectively; t Q ox = assumed or known discharge in pipe x for the t th iteration; and t ΔH i, t ΔH j and t ΔQ x = the unknown corrections for the t th 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 ΔQ x on the left hand side t+1h i t+1 H j n R ox t Q ox n-1 tδq x = R ox t Q n ox, x = 1,.,X Eqn 2 in which t+1 H i and t+1 H j = corrected nodal heads after the t th iteration at nodes i and j, respectively. Subtracting n R ox t Q n oxfrom both sides t+1h i t+1 H j n R ox t Q ox n-1 ( t Q ox + t ΔQ x ) = (1-n)Rox tq n ox, x = 1,.,X Eqn 3 Replacing t Q ox + t ΔQ x by t+1 Q x t+1h i t+1 H j (n R ox t Q ox n-1 ) t+1 Q x = (1-n)R ox t Q n ox, 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 +1Q x + q o j = 0, j = M + 1,., M + N Eqn 5 311

5 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 t Q ox 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 = 0.85C H R 0.63 S 0.64 Where, C H = 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 N and 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 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 312

6 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 MLD in Population Rate of lpcd Qty MLD in Population 1 Domestic Demand Institutional Demand Public Use Demand Total Net Demand Total Gross Demand with 15% Losses 6 Max.Design Demand (2.7 x Total Gross) Rate of lpcd Qty MLD 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 in 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.) / / / / / / / / / / / / / / / / / / / / / / /- - - Total cost 78,97543/- Total cost 34,30432/- Total cost 1,36,90746/- 313

7 Figure 1: Schematic diagram of a real network showing all Nodes Figure 2: Schematic diagram of a real network showing all Pipe section Figure 3: Optimal layout of network with Node data for DI pipe 314

8 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 315

9 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 316

10 CONCLUSION Figure 8: Optimal layout of network with Pipe section data for CI pipe 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 317

11 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 1. Chambers, K., Creasey, J., and Forbes, L., Design and Operation Distribution Networks, World Health Organisation, IWA Publishing, London, UK, 2004, pp Swamee, P. K., and Sharma, A. K., Design of Water Supply Pipe Networks, A John Wiley & Sons, Publication, Inc., Hoboken, New Jersey, 2008, pp. 1-9, Bhave, P., and Gupta R., Analysis of Water Distribution Networks, Narosa Publishing House, Navi Mumbai, 2011, pp Garg., S. K., Water Supply Engineering, Vol. 1, Khanna Publishers, New Delhi, 2008, pp Modak, P., and Rabbani, W., Optimal Design of Water Supply Networks Journal of Environmental Engineering, Vol. 110, ASCE, 1984, pp Bhave, P., Optimization of Gravity-Fed Water Distribution Systems: Theory, Journal of Environmental Engineering, Vol. 109 (1), American Society of Civil Engineers (ASCE), 1983, pp Chiplunkar, A., and Khanna, P., Optimal Design of Branched Water Supply Networks, Journal of environmental Engineering, Vol. 109 (3), ASCE, 1983, pp Alperovits, E. and Shamir, U., Design of Optimal Water Distribution Systems, Journal of Water Resources Research, Vol. 13 (6), American Geophysical Union, 1977, pp Dabhade, P. D., and Regulwar, D. G., Optimal Design of Water Supply Network By Using Piping System Fluidflow, Journal of Enviromental Engineering and Management, Vol.3 (2), 2012, pp Chandapillai, J., Design of Water Distribution Network for Equitable Supply, Journal of Water Resources Planning and of Management, Vol. 26, Springer, 2012, pp

12 11. Lansey, K. E., Duan, N., Mays, L. W., and Tung, Y. K., Water Distribution System Design Under Uncertainties, Journal of Water Resources Planning and Management, Vol. 115 (5), ASCE, 1989, pp Young, B., Design of Branched-Water-Supply-Network on Uneven Terrain, Journal of Environmental Engineering, Vol. 120(4), ASCE, 1994, pp Varma, V. K., Narasimhan, S. and Bhallamudi, S. M., Optimal Design of Water Distribution Systems Using an NLP Method, Journal of Environmental Engineering, Vol. 123 (4), ASCE, 1997, pp Vasan, A. and Simonovic, P., Optimization of Water Distribution Network Design UsingDifferential Evolution, Journal of Water Resources Planning and Management, Vol. 136 (2), ASCE, 2010, pp Bhave, P. R., and Lam, C. F., Optimal Layout For Branching Distribution Networks, Journal of Transporation Enginnering, Vol. 109 (4), ASCE, 1983, pp Cunha, M. D., and Sousa, J., Water Distribution Network Design Optimization: Simualted Annealing Approach, Journal of Water Resources Planning and Management, Vol. 125 (4), ASCE, 1999, pp Bentley Systems Software Ltd, WaterGEMS software V8i & User s Guide, Bentley Systems Ltd,