Design Of Water Distribution Systems Research Articles

Seismic Reliability–Based Multiobjective Design of Water Distribution System: Sensitivity Analysis

AbstractThis study proposes a seismic reliability–based water distribution system (WDS) optimal design model that minimizes total cost and maximizes seismic reliability. Here, seismic reliability is defined as the ratio of the available quantity of water to the required demand under stochastic earthquake events. A new evaluation model is used to assess seismic reliability, while a multiobjective harmony search (MOHS) based on a ranking approach is used for optimization. The Anytown network was modified for the demonstration of the proposed method. First, this study performs the sensitivity analysis of MOHS parameter values [i.e., harmony search consideration rate (HMCR) and pitch adjustment rate (PAR)] to identify the best parameter set in a pipe-sizing problem of an Anytown network. Then, Pareto optimal solutions with three different tank configurations are obtained and compared with respect to the final Pareto fronts and the system designs. For the sensitivity analysis, it reveals that higher PAR and lo...

Serious Gaming for Water Systems Planning and Management

Water systems planning and management share the same roots with gaming, as they rely on concepts in systems analysis, operations research and decision sciences. This paper focuses on Serious Games (those used for purposes other than mere entertainment), with applications in the area of water systems planning and management. A survey of published work on gaming is carried out with particular attention given to applications of Serious Gaming to water systems planning and management. The survey is also used to identify the principal criteria for the classification of Serious Gaming for water related applications, including application areas, goals, number and type of players, user interface, type of simulation model used, realism of the game, performance feedback, progress monitoring and game portability. The review shows that game applications in the water sector can be a valuable tool for making various stakeholders aware of the socio-techno-economic issues related to managing complex water systems. However, the critical review also indicates a gap that exists in the Serious Game application area with the lack of water distribution system games. A conceptually simple, but computationally elaborate new game for water distribution system analysis, design and evaluation (SeGWADE) is presented in this paper. It has a main goal of finding a least-cost design for a well-known benchmark problem, for which the game environment takes the computational and visualisation burden away from the simulation tool and the player. The game has been evaluated in a classroom environment in which a high degree of player engagement with the game was observed, due to its basic game ingredients and activities, i.e., challenge, play and fun. In addition, a clear improvement in learning has been observed in how players attempted to identify solutions that satisfy the pressure criterion with players readily identifying the proximity of the better solutions to the starting, infeasible configuration. Through applications of Serious Gaming such as this, decision makers can learn about the complexity of the water distribution system design problem, experiment safely using a computer model of a real system, understand conflicting objectives (i.e., minimization of cost and satisfaction of minimum pressure) and develop strategies for coping with complexity without being burdened by the limitations of the ICT technology at their disposal.

Reliability Surrogate Measures for Water Distribution System Design: Comparative Analysis

AbstractBecause of the large computational burden associated with the direct assessment of reliability, the indirect indices of reliability have recently received more attention in the framework of water distribution system design. Two new energy-related indices for reliability evaluation (i.e., available power index and pipe hydraulic resilience index) are developed in this paper. The performance of these new indices is evaluated and compared with that of four existing indices (three other energy-related indices—i.e., resilience index, network resilience index, and modified resilience index—and the entropy-based method, i.e., diameter-sensitive flow entropy) according to the following two-step methodology. In the first step, the application of the multiobjective optimization makes it possible to determine optimal network configurations that trade-off the installation cost (to be minimized) against the generic indirect reliability index (to be maximized). In the second step, the performance of the optimal...

Water Quality Based Multi-objective Optimal Design of Water Distribution Systems

Water distribution systems (WDSs) are one of the vital infrastructures in urban areas. The common objective considered in WDSs design is providing required water with the minimum construction cost. Less attention is paid to “water quality” as an objective in optimal design of WDSs. The aim of this paper is to include a water quality based objective in WDS design alongside other common objectives. For this purpose, the water quality reliability index developed based on “chlorine residual” and “water age”, is used. EPANET2.0 is applied for WDS simulation and ACO (Ant-Colony-Optimization) has been used as the optimization algorithm. Head-Driven-Simulation-Method (HDSM) is also considered. The proposed model is applied to Jahrom (a city in the south of Iran) WDS. The outputs show that the proposed model would result in less construction costs in comparison to the original design and 4–10 % of construction cost can be reduced depending on the considered objectives and selected optimal solution by managers and decision makers while the resulted solutions include high water quality reliability (ranging from 93 to 99 %). Also using HDSM method for hydraulic analysis of WDS instead of DDSM can lead to solutions with less construction cost (U$10,000 in average) and acceptable water quality reliability.

Design of Water Distribution System: Appropriateness of Structured System in Large Irrigation Projects in Nepal

Many large irrigation projects in Nepal operate under command area development works that emphasize on-farm water distribution and management. These projects have specific design characteristics that were planned to comply with available water resources, climatic conditions, soil type, and water distribution technology. The water distribution technologies differ based on the design needs of each individual project and the design preferences of various foreign consulting firms. This article focuses on the issues of planning and designing water distribution systems of large irrigation systems at the irrigation service delivery level. The layout planning of an irrigation system is an important aspect of design for water distribution, typically guided by hierarchical system. This article also highlights the existing canal hierarchy of these systems and their appropriateness for efficient water distribution. Furthermore, the appropriateness of the structured system is also examined in the Sunsari Morang Irrigation Project. The article concluded with some suggestions for planning and designing command area development works of forthcoming large irrigation projects such as the Sikta Irrigation Project, the Babai Irrigation Project, and the Mahakali Irrigation Project Stage-III.HYDRO Nepal JournalJournal of Water, Energy and EnvironmentIssue: 19Page: 25-30

Calibration of Water Demand Multipliers in Water Distribution Systems Using Genetic Algorithms

AbstractHydraulic models have been widely used for design, analysis, and operation of water distribution systems. As with all hydraulic models, water demands are one of the main parameters that cause the most uncertainty to the model outputs. However, the calibration of the water demands is usually not feasible attributable to the limited quantity of available measurements in most real water networks. This paper presents an approach to calibration of the demand multiplier factors under an ill-posed condition where the number of measurements is less than the number of parameter variables. The problem is solved using a genetic algorithm (GA). The results show that not only is the GA able to match the calibrated values at measured locations, but by using multiple runs of the GA model, the flow rates and nodal heads at nonmeasured locations can be estimated. Three case studies are presented as an illustration of the problem. The first case study is a small network that demonstrates the calibration model. The ...

Penalty-Free Multi-Objective Evolutionary Approach to Optimization of Anytown Water Distribution Network

This paper describes the development and application of a new multi-objective evolutionary optimization approach for the design and upgrading of water distribution systems with multiple pumps and service reservoirs. The optimization model employs a pressure-driven analysis simulator that accounts for the minimum node pressure constraints and conservation of mass and energy. Pump scheduling, tank siting and tank design are integrated seamlessly in the optimization without introducing additional heuristic procedures. The computational solution of the optimization problem is entirely penalty-free, thanks to pressure-driven analysis and the inclusion of explicit criteria for tank depletion and replenishment. The model was applied to the Anytown network that is a benchmark optimization problem. Many new solutions were achieved that are cheaper and offer superior performance compared to previous solutions in the literature. Detailed and extensive simulations of the solutions achieved were carried out. Spatial and temporal variations in water quality were investigated by simulating the chlorine residual and disinfection by-products in addition to water age. The hydraulic requirements were satisfied; efficiency of pumps was consistently high; effective operation of the new and existing tanks was achieved; water quality was improved; and overall computational efficiency was high. The formulation is entirely generic.

Least-Cost Robust Design Optimization of Water Distribution Systems under Multiple Loading

AbstractLeast-cost design of water distribution system is a well-known problem in the literature. The formulation of the least-cost design problem started by deterministic modeling and later by more sophisticated stochastic models that incorporate uncertainties related to the problem’s parameters. Recently, a new nonprobabilistic modeling, titled the robust counterpart (RC) approach, has been developed for the least-cost design problem to incorporate the uncertainty without the need for full stochastic information. These nonprobabilistic methods, developed in the field of robust optimization, were shown to be advantageous over classical stochastic methods in the following aspects: tractability and computation time, nonnecessity of full probabilistic information, and the ability to integrate correlation of uncertain parameters aspects without adding complexity. Former studies have considered the RC approach for a special case of the least-cost problem with a single load demand uncertainty, and single gravi...

Use of Domain Knowledge to Increase the Convergence Rate of Evolutionary Algorithms for Optimizing the Cost and Resilience of Water Distribution Systems

AbstractEvolutionary algorithms (EAs) have been used extensively for the optimization of water distribution systems (WDSs) over the last two decades. However, computational efficiency can be a problem, especially when EAs are applied to complex problems that have multiple competing objectives. In order to address this issue, there has been a move toward developing EAs that identify near-optimal solutions within acceptable computational budgets, rather than necessarily identifying globally optimal solutions. This paper contributes to this work by developing and testing a method for identifying high-quality initial populations for multiobjective EAs (MOEAs) for WDS design problems aimed at minimizing cost and maximizing network resilience. This is achieved by considering the relationship between pipe size and distance to the source(s) of water, as well as the relationship between flow velocities and network resilience. The benefit of using the proposed approach compared with randomly generating initial popu...

Impact of Starting Position and Searching Mechanism on the Evolutionary Algorithm Convergence Rate

AbstractEvolutionary algorithms (EAs) have been used extensively to find globally optimal solutions for water distribution system (WDS) optimization problems. However, as these algorithms are being applied to increasingly complex systems, computational efficiency is becoming an issue, and hence approaches that enable near-optimal solutions to be identified within reasonable computational budgets have received increasing attention. One of these approaches is the initialization of EAs in a manner that accounts for domain knowledge of WDS design problems. Although the effectiveness of these initialization approaches has been studied previously, the impact of algorithm searching behavior on the speed with which near-optimal solutions can be found has not yet been examined. To this end, this study aims to investigate the relative impact of different algorithm initialization methods and searching mechanisms on the speed with which near-optimal solutions can be identified for large WDS optimization problems. Fit...

Enhanced Artificial Neural Networks Estimating Water Quality Constraints for the Optimal Water Distribution Systems Design

AbstractOptimal water distribution system (WDS) design including the layout and pipe sizes is invariably complex, even when hydraulic constraints alone are considered. The addition of water quality (WQ) constraints adds to the computational demands. Using conventional WQ models to evaluate the feasibility of the many networks that must be analyzed can extend the optimization process beyond acceptable limits. Artificial neural networks (ANNs) can approximate disinfectant concentrations in a fraction of the time required by deterministic WQ models, and thus have been used for WDS pipe optimization as fast surrogates of these models. This study seeks to improve the performance of ANNs applied to the optimal design of WDSs by comparing their outcomes on the basis of ANN architecture and data used for ANN training, two factors that affect their speed and accuracy. ANNs were trained to forecast the disinfectant concentration at the relevant nodes of two case studies: A simple WDS (common in the literature of WD...

Pressure Standards in Water Distribution Systems: Reflection on Current Practice with Consideration of Some Unresolved Issues

AbstractPressure standards assist in the design of water distribution systems and the assessment of their performance. Although exact thresholds are sometimes rather vague, unusually high and low pressures are widely understood to increase costs and put systems at risk from events like pipe bursts at the high-pressure end to the risk of contaminant intrusion or poor firefighting conditions at the low-pressure end. Interestingly, because the definition of what conditions constitute acceptable pressures differs around the world, a delivery pressure might be considered acceptable in some regions and unacceptable in others. But if a wider range of system conditions is considered, including transient events, an interesting question arises as to what exactly the standards might mean and how violations should be evaluated. Specifically, what kinds of pressure transgressions are most crucial to system performance and economics and what kinds are merely inconvenient? Certainly the issue of evaluating consequences ...

Comparison of the Searching Behavior of NSGA-II, SAMODE, and Borg MOEAs Applied to Water Distribution System Design Problems

AbstractA number of multiobjective evolutionary algorithms (MOEAs) have been developed and applied to water resource optimization problems over the past decade. The comparative performance of these MOEAs has been investigated often according to their overall end-of-run results (quality of optimal fronts) within prespecified computational budgets. Despite the importance of such comparative analyses, these studies have provided little knowledge of how different MOEAs navigate through the decision space toward the Pareto front. To address this issue, this paper uses a range of metrics to quantitively characterize MOEAs’ run-time searching behavior, with a focus on the statistics of search quality and convergence progress. The metrics are applied to three state-of-the-art MOEAs, including the nondominated sorting genetic algorithm-II (NSGA-II), self-adaptive multiobjective differential evolution (SAMODE), and Borg, for six water distribution system (WDS) design problems with the objectives of minimizing netwo...

Erratum for “Evaluating Flexibility in Water Distribution System Design under Future Demand Uncertainty” by Innocent Basupi and Zoran Kapelan

Zoran Kapelan Professor, Centre for Water Systems, College of Engineering, Mathematics and Physical Sciences, Univ. of Exeter, North Park Rd., Harrison Bldg., Exeter EX4 4QF, U.K. E-mail: Z.Kapelan@exeter.ac.uk The captions and images of Figs. 4–14 were inadvertently interchanged in the final published paper. The figures with the correct images and captions are included herewith. This correction affects some in-text references to the figures. The first paragraph of the “Case Studies” section should reference Figs. 4–10 and 13. The “Results and Discussion” section of the New York Tunnels case study references Figs. 4, 5, 8, and 13. The Note to Table 1 should refer to Figs. 4–7. On page 0401403410, the reference to Figs. 6–10 should be replaced with Figs. 6, 7, 9, and 10. ASCE regrets the errors.

Biological Stability of Drinking Water: Controlling Factors, Methods, and Challenges.

Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and can lead to hygienic (e.g., development of opportunistic pathogens), aesthetic (e.g., deterioration of taste, odor, color) or operational (e.g., fouling or biocorrosion of pipes) problems. Drinking water contains diverse microorganisms competing for limited available nutrients for growth. Bacterial growth and interactions are regulated by factors, such as (i) type and concentration of available organic and inorganic nutrients, (ii) type and concentration of residual disinfectant, (iii) presence of predators, such as protozoa and invertebrates, (iv) environmental conditions, such as water temperature, and (v) spatial location of microorganisms (bulk water, sediment, or biofilm). Water treatment and distribution conditions in water mains and premise plumbing affect each of these factors and shape bacterial community characteristics (abundance, composition, viability) in distribution systems. Improved understanding of bacterial interactions in distribution systems and of environmental conditions impact is needed for better control of bacterial communities during drinking water production and distribution. This article reviews (i) existing knowledge on biological stability controlling factors and (ii) how these factors are affected by drinking water production and distribution conditions. In addition, (iii) the concept of biological stability is discussed in light of experience with well-established and new analytical methods, enabling high throughput analysis and in-depth characterization of bacterial communities in drinking water. We discussed, how knowledge gained from novel techniques will improve design and monitoring of water treatment and distribution systems in order to maintain good drinking water microbial quality up to consumer’s tap. A new definition and methodological approach for biological stability is proposed.

Developed Swarm Optimizer: A New Method for Sizing Optimization of Water Distribution Systems

AbstractThe introduction of metaheuristic algorithms in water resources engineering has greatly raised the need for continued development of appropriate optimization methodologies for analysis, planning, design, and operation of water resources systems. This paper proposes a novel developed swarm-based optimization algorithm named DSO, which integrates the accelerated particle swarm optimization (PSO) with the big bang-big crunch algorithm (BB-BC) to optimize the design of water distribution systems (WDSs). Traditional PSO is easy to fall into stagnation when no particle explores a position that is better than its previous best position for several iterations. To deal with the problem of maintaining diversity within the swarm and to enhance the exploration in the search, the concepts of the Big Crunch and Big Bang strategies from the BB-BC algorithm are incorporated into the global and local searching steps of the accelerated PSO, respectively. In addition, a harmony search–based strategy is used to contr...

Uncertainty in the Analysis of Water Conveyance Systems

Conventionally, the design of water conveyance and distribution systems is based on the assumption that all the involved parameters are known a priori and remain unaltered throughout the life cycle of the system. This type of approach offers simplicity in the calculations by neglecting a variety of uncertainties which accompany the parameters and processes involved. However, significant uncertainties do appear during the analysis and design of these systems, such as the equivalent pipe roughness and the actual internal diameters of the pipes. Furthermore, the demands at the nodes of the system are dependent on several ambiguous assumptions which are not always met at the operation stage. To deal with these uncertainties, several mathematical data demanding approaches have been proposed in the past. In this study these uncertainties are incorporated in the analysis of the system, using the extension principle of the fuzzy sets and a new operation of the fuzzy subtraction. Based on the calculation of head losses for each branch of the system, the nodal heads are derived as fuzzy numbers. The proposed methodology, being a low data demand methodology, is illustrated by a numerical example of a water conveyance system.

A hybrid cuckoo–harmony search algorithm for optimal design of water distribution systems

Meta-heuristic algorithms have been broadly used to deal with a range of water resources optimization problems over the past decades. One issue that exists in the use of these algorithms is the requirement of large computational resources, especially when handling real-world problems. To overcome this challenge, this paper develops a hybrid optimization method, the so-called CSHS, in which a cuckoo search (CS) algorithm is combined with a harmony search (HS) scheme. Within this hybrid framework, the CS is employed to find the promising regions of the search space within the initial explorative stages of the search, followed by a thorough exploitation phase using the combined CS and HS algorithms. The utility of the proposed CSHS is demonstrated using four water distribution system design problems with increased scales and complexity. The obtained results reveal that the CSHS method outperforms the standard CS, as well as the majority of other meta-heuristics that have previously been applied to the case studies investigated, in terms of efficiently seeking optimal solutions. Furthermore, the CSHS has two control parameters that need to be fine-tuned compared to many other algorithms, which is appealing for its practical application as an extensive parameter-calibration process is typically computationally very demanding.

Robustness-based optimal pump design and scheduling for water distribution systems

We introduce a new system robustness index for optimizing the pump design and operation of water distribution systems. Here, robustness is defined as a system's ability to continue functioning under varying demand conditions. The maximum difference between the daily maximum and minimum pressures of a node was taken as a robustness indicator and incorporated as a constraint in a pump design and operation model that minimizes the total pump cost (construction and operation cost). Two well-known benchmark networks, the Apulian and Net2 networks, were modified and used to demonstrate the proposed model. The Pareto relationship between the total cost and system robustness was explored through independent optimizations of the model for different robustness constraint values. The resulting solutions were compared to the traditional least-cost solution. Regardless of the study networks, considering the robustness resulted in a greater number of small pumps compared with the least-cost solution. A sensitivity analysis on tank capacity was performed with the Apulian network. The proposed model is the pump design and operation tool that accounts for both the total pump cost and system robustness, which are the most important factors considered by water distribution operators.

Real-World Considerations in Water Distribution System Design

Engineering schools generally do a very good job teaching the fundamentals of water distribution system design. However, there are a good number of practical considerations in system design that seem to be ignored in the research literature. This paper attempts to present some important considerations in system design that are important but generally are overlooked in many research papers. Some of the considerations that are described in this paper include the types of water system planning; sources of funding and their effects; dealing with uncertainty, especially in demand forecasts; construction sequencing; and other issues that must be considered in design. The paper focuses on practices common to the United States but most of the content should be relevant in other locations. System design is driven by the need to reliably provide adequate water to customers at adequate pressure and quality while maintaining water rates (customer prices) at a reasonable level. In the early days of centralized water systems, this involved tedious manual calculations and conservative designs. As computer technology advanced, hydraulic analysis models relieved engineers from tedious calculations and enabled them to consider much more detail and perform more analyses to arrive at generally better designs. Researchers have prepared hundreds of papers on application of optimization of water system design, mostly focusing on pipe sizing. While these papers can provide some insights to practicing engineers, real-world details often need to be neglected to force the real problem to acquiesce to the optimization formulation, which usually involves minimizing some objective function(s) subject to some constraints. Hopefully, this paper can point out some considerations that need to be accounted for in any analysis of water system design. Each consideration is described with its implications in the following sections.