Management Of Water Distribution Systems Research Articles

Management of water distribution systems in PDA conditions using isolation valves: case studies of real networks

Abstract The current paper reports on a case study investigating water distribution system management in emergency conditions when it is necessary to seal off a zone with isolation valves to allow repair. In these conditions, the pressure-driven analysis (PDA) is considered to be the most efficient approach for the analysis of a water distribution network (WDN), as it takes into account whether the head in a node is adequate to ensure service. The topics of this paper are innovative because, until now, previous approaches were based on the analysis of the network behaviour in normal conditions. In emergency conditions, it is possible to measure the reliable functioning of the system by defining an objective function (OF) that helps to choose the optimal number of additional valves in order to obtain adequate system control. The OF takes into account the new network topology by excluding the zone where the broken pipe is located. The results show that the solution did not improve significantly when the number of valves reached a threshold. The procedure applied to other real case studies seems to confirm the efficiency of the methodology even if further examination of other cases in different conditions is necessary.

Topographic Energy Management in Water Distribution Systems

A significant amount of energy is required to operate pressurised water distribution systems, and therefore, improving their efficiency is crucial. Traditionally, more emphasis has been placed on operational losses (pumping inefficiencies, excess leakage or friction in pipes) than on structural (or topographic) losses, which arise because of the irregular (unchangeable) terrain on which the system is located and the network’s layout. Hence, modifying the network to adopt an ecologically friendly layout is the only way to reduce structural losses. With the aim of improving the management of water distribution systems and optimising their energy use, this work audits and classifies water networks’ structural losses (derived from topographic energy), which constitutes the main novelty of this paper. Energy can be recovered with PATs (pumps as turbines) or removed through PRVs (pressure reducing valves). The proposed hydraulic analysis clarifies how that energy is used and identifies the most suitable strategy for improving efficiency as locating the most suitable place to install PRVs or PATs. Two examples are discussed to illustrate the relevance of this analysis.

Development of Failure Cause–Impact–Duration (CID) Plots for Water Supply and Distribution System Management

Understanding the impact and duration (consequences) of different component failures (cause) in a water supply and distribution system (WSDS) is a critical task for water utilities to develop effective preparation and response plans. During the last three decades, few efforts have been devoted to developing a visualization tool to display the relationship between the failure cause and its consequences. This study proposes two visualization methods to effectively show the relationship between the two failure entities: A failure cause–impact–duration (CID) plot, and a bubble plot. The former is drawn for an effective snapshot on the range (extent) of failure duration and the impact of different failures, whereas the latter provides failure frequency information. A simple and practical failure classification system is also introduced for producing the two proposed plots effectively. To verify the visualization schemes, we collected records of 331 WSDS component failures that occurred in South Korea between 1980 and 2018. Results showed that (1) the proposed CID plot can serve as a useful tool for identifying most minor and major WSDS failures, and (2) the proposed bubble plot is useful for determining significant component failures with respect to their failure consequences and occurrence likelihoods.

Detecting urban water consumption patterns: a time-series clustering approach

Abstract The need for efficient management of water distribution systems is a growing concern for economic, environmental and social reasons. Water supply systems are commonly designed to ensure adequate behaviour under the worst conditions, such as maximum consumption, which leads to overestimation in supply tanks and energy waste. While overestimation should be considered, to account for unpredictable demands and emergency scenarios, we advocate that a detailed understanding of consumption patterns enables an improvement in water management and is additionally beneficial to correlated resources such as electricity. A novel framework to detect water consumption patterns is developed and applied to an urban scenario. Observed discrepancies among computed patterns enable readjustments of supplied water flowrate, thus promoting effective water allocation and pumping costs, while mitigating water contamination risks.

Thinking Outside the Treatment Plant: UV for Water Distribution System Disinfection.

This work critically evaluates the current paradigm of water distribution system management and juxtaposes that with the potential benefits of employing UV irradiation, which we hope will catalyze a judicial re-evaluation of the current practices in water distribution system management and spur critical research and a new way of thinking about secondary disinfection across the extent of distribution systems. Given the recent advances in UV technology and the efficacy of UV disinfection against all pathogen classes, we now see UV applications for disinfection in many aspects of consumers lives: in water coolers, dishwashers, coffee makers, and disinfection of personal items like gym bags, water bottles, and toothbrushes. Public and regulatory concern over water quality and pathogens, especially the recent interest in building plumbing, calls out for new approaches to disinfection and distribution system management. We envision a new model for secondary disinfection in water distribution systems utilizing emerging germicidal UV LED-based disinfection. UV irradiation in water treatment can achieve high levels of disinfection of all pathogens and minimize or eliminate the formation of regulated disinfection byproducts. So why is UV not considered as a secondary disinfectant for distribution systems? In this Account, we lay out the logic as to the benefits and practicality of adding distributed UV treatment to assist in protection of distribution systems and protect water quality for human exposure. The possible locations of UV irradiation in distribution systems are envisioned, potentially including UV booster stations along the distribution network, UV in storage tanks or their inlet/outlets, LEDs distributed along pipe walls, small point of use/entry treatment systems for buildings/homes/taps, or submersible swimming or rolling UV LED drones to reach problem pipes and provide a "shock" treatment or provide sterilization after main breaks or repairs. The benefits of UV applications in water also include high effectiveness against chlorine-resistant protozoa, no added disinfection byproducts, and compatibility of adding of UV to existing secondary disinfection strategies for enhanced protection. Potential challenges and research needs are described, such as use of UV-compatible pipe materials, implementation of sensors to monitor distributed LEDs, management of waste heat from the rear surface of the LED, and understanding the potential for regrowth of opportunistic microorganisms. Another notable challenge is the relatively stagnant regulatory environment in some countries to develop frameworks for evaluation and acceptance of UV technology in distribution systems that require a chemical secondary disinfectant. Rapid advances in UV LED research has propelled the growth of this field, but needs still remain, including understanding behavior of biofilms in pipes under UV irradiation, including any beneficial effects that may be lost, the potential for fouling of LED emission surfaces and monitoring points, and provision of a distributed power network to run the LEDs. Regulators may want specific monitoring approaches and advances in real-time monitoring of microbial viability, and engineers may need to develop new approaches to overall management.

Optimal Selection and Monitoring of Nodes Aimed at Supporting Leakages Identification in WDS

Many efforts have been made in recent decades to formulate strategies for improving the efficiency of water distribution systems (WDS), led by the socio-demographic evolution of modern society and the climate change scenario. The improvement of WDS management is a complex task that can be addressed by providing services to maximize revenues while ensuring that the quality standards required by national and international regulations are upheld. These two objectives can be fulfilled by utilizing optimized techniques for the operational and maintenance strategies of WDS. This paper proposes a methodology for assisting engineers in identifying water leakages in WDS, thus providing an effective procedure for ensuring high level hydraulic network functionality. The proposed approach is based on an inverse analysis of measured flow rates and pressure data, and consists of three steps: The analysis of measurements to select the most suitable period for leakage identification, the localization of the best measurement points based on a correlation analysis, and leakage identification with a hybrid optimization that combines the exploration capability of the differential evolution algorithm with the rapid convergence of particle swarm optimization. The proposed procedure is validated on a reference hydraulic network, known as the Apulian network.

Distribution Systems: Has Asset Management Made a Difference?

AbstractSuccessful management of water distribution systems will rise in importance as more people gain access to piped water globally. While much research about the management of these systems has...

Management of uncertain pairwise comparisons in AHP through probabilistic concepts

Fast and judicious decision-making is paramount for the success of many activities and processes. However, various degrees of difficulty may affect the achievement of effective and optimal solutions. Decisions should ideally meet the best trade-off among as many of the involved factors as possible, especially in the case of complex problems. Substantial cognitive and technical skills are indispensable, while not always sufficient, to carry out optimal evaluations. One of the most common causes of wrong decisions derives from uncertainty and vagueness in making forecasts or attributing judgments. The literature shows numerous efforts towards the optimization and modeling of uncertain contexts by means of probabilistic approaches. This paper proposes the use of probability theory to estimate uncertain expert judgments within the framework of the analytic hierarchy process and, more specifically, within a linearization scheme developed by the authors. After describing the necessary probabilistic concepts of interest, the main results are developed. These results can be summarized as using various kinds of random variables with uncertainty embodied in undecided pairwise comparisons. A case study focused on the maintenance management of an industrial water distribution system exemplifies the approach.

Changes on Eubacteria 338I, Gamma-, Betaproteobacteria in Biofilms from Drinking Water Systems According to Operational Conditions

Biofilms in drinking water network are ubiquitous, hosting bacteria that must be assessed and controlled, particularly pathogens. Bacterial population can be affected by operational conditions in the network. Variables including distance, time of stabilization, velocity and high (biofilm 1) and low (biofilm 2) chlorine were assessed as modifiers of bacterial population, in a pilot-scale system during a long-term period and laminar conditions. Gram-positive bacteria and other Proteobacteria, pathogens and versatile bacteria were quantified in biofilm samples by fluorescent in situ hybridization (FISH), using respectively Eubacteria 338I, Gamma- and Betaproteobacteria probes. Denaturing Gradient Gel Electrophoresis (DGGE) analyses were also performed to determine similarity between samples. Based on results, a high heterogeneity was observed even at short length (3 m: <40% similarity). The time of stabilization changed the effect of velocity over bacterial population. After 169 days, water velocity was negatively correlated with Betaproteobacteria (r = −0.71; p = 0.11 in biofilm 1) and Eubacteria 338I (r = −0.91; p = 0.01 in biofilm 2), while at the end, Eubacteria 338I from biofilm 2 correlated positively with water velocity (r = 0.78; p = 0.06). Chlorine favored the proliferation of Gamma-, Betaproteobacteria, especially in biofilm 1, being Gammaproteobacteria counts one order higher than in biofilm 2. Chlorine proved to be the most influential operational condition on the bacterial population, because it benefited the group characterized by pathogenicity. Due to the scarce information about mature biofilms at low flux conditions, this study contributes to the understanding on Eubacteria 338I, Gamma- and Betaproteobacteria populations, thus to water distribution system management in rural operation.

Leakage Estimation in Water Distribution Network: Effect of the Shape and Size Cracks

The definition of the relationship between the leak outflow, the total head at the leak and other relevant parameters such as pipe stiffness, leak dimension and shape has been object of extensive studies. The attention to a correct estimation of leakages, leak law, is crucial for the management of water distribution systems. Water utilities, in fact, can reduce leakage levels through the leak detection or more usually by pressure management. In the last cases, the known of the relationship between leak discharge and pressure is fundamental. In recent decades, the use of the Torricelli equation has been questioned, because some experimental results showed that it can yield unsatisfactory results, and other formulations have been suggested to model water leakages in water distribution networks. To investigate the effectiveness of the formulations suggested by different authors, an experimental campaign was carried out at the Environmental Hydraulic Laboratory of the University of Enna (Italy) for leaks of different shape and size in polyethylene pipes. The results of the laboratory experiments contribute to clarify the applicability of the leak law for circular and rectangular leaks and suggest that Torricelli formulation is valid in absence of leak area deformation. Furthermore, the analysis contributes to the knowledge of the coefficients of the leak laws used to estimate the leakage outflow.

Risk management of water distribution system in Armenia

Risks in the water distribution system in the Armenian village of Noratus, have been assessed and treated following a risk management study based on the ISO 31 000:2009 standards, but extended for a strategic and long term level of analysis. The main goal is to ensure the safety of the whole water supply system. The brief description of the region as well as the current condition of the water supply system is given in order to clarify system features. The risk management here presented approach is now implemented in the Noratus network. Simulation have been performed using the AWARE-P software platform with the purpose of identifying critical components in the network and the asset probability of structural failure, as inputs for risk quantification. Then the risk magnitude is evaluated with the introduction of risk matrix. The phases of risk estimation and treatment are also carried out to propose the solutions for risk level reduction.

Trends in metering potable water

Abstract Sustainable management of drinking water distribution systems requires information on the operating status of system components to identify the best operational management measures. The ability to acquire information on tank levels, pipeline flow and real-time pressure offers an efficient and cost-effective management perspective, and enables wider monitoring, which can improve (physical) security as well. The technology of measuring instruments for hydrodynamic variables, used to monitor potable water systems, differs in their independence from electronic data acquisition components and ability to connect to remote data communication systems. Advanced water measurement infrastructure is characterized by the ability to capture data with measurable errors from anywhere in the system, without restrictions on communication type. This paper deals with the measurement of hydrodynamic parameters and a proposal for water meter classification. It includes analysis of the main water meter and data tele-acquisition infrastructure. Several selection criteria are evaluated with respect to their ability to support mathematical hydraulic models and expert systems for water distribution system management.

Efficient Numerical Approach for Simultaneous Calibration of Pipe Roughness Coefficients and Nodal Demands for Water Distribution Systems

AbstractHydraulic models have been widely used to facilitate the design, management, and operation of water distribution systems (WDS). However, model parameters including pipe roughness coefficien...

Vulnerability Assessment to Trihalomethane Exposure in Water Distribution Systems

Chlorination is an effective and cheap disinfectant for preventing waterborne diseases-causing microorganisms, but its compounds tend to react with the natural organic matter (NOM), forming potentially harmful and unwanted disinfection by-products (DBPs) such as trihalomethanes (THMs), haloacetic acids (HAAs), and others. The present paper proposes a methodology for estimating the vulnerability with respect to users’ exposure to DPBs in water distribution systems (WDSs). The presented application considers total THMs (TTHMs) concentration, but the methodology can be used also for other types of DPBs. Five vulnerability indexes are adopted that furnish different kinds of information about the exposure. The methodology is applied to five case studies, and the results suggest that the introduced indexes identify different critical areas in respect to elevated concentrations of TTHMs. In this way, the use of the proposed methodology allows identifying the higher risk nodes with respect to the different kinds of exposure, whether it is a short period of exposure to high TTHMs values, or chronic exposure to low concentrations. The application of the methodology furnishes useful information for an optimal WDS management, for planning system modifications and district sectorization taking into account water quality.

Topological attributes of network resilience: A study in water distribution systems

Resilience has been increasingly pursued in the management of water distribution systems (WDSs) such that a system can adapt to and rapidly recover from potential failures in face of a deep uncertain and unpredictable future. Topology has been assumed to have a great impact on resilience of WDSs, and is the basis of many studies on assessing and building resilience. However, this fundamental assumption has not been justified and requires investigation. To address this, a novel framework for mapping between resilience performance and network topological attributes is proposed. It is applied to WDSs here but can be adaptable to other network systems. In the framework, resilience is comprehensively assessed using stress-strain tests which measure system performance on six metrics corresponding to system resistance, absorption and restoration capacities. Six key topological attributes of WDSs (connectivity, efficiency, centrality, diversity, robustness and modularity) are studied by mathematical abstraction of WDSs as graphs and measured by eight statistical metrics in graph theory. The interplay between resilience and topological attributes is revealed by the correlations between their corresponding metrics, based on 85 WDSs with different sizes and topological features. Further, network variants from a single WDS are generated to uncover the value of topological attribute metrics in guiding the extension/rehabilitation design of WDSs towards resilience. Results show that only certain aspects of resilience performance, i.e. spatial and temporal scales of failure impacts, are strongly influenced by some (not all) topological attributes, i.e. network connectivity, efficiency, modularity and centrality. Metrics for describing the topological attributes of WDSs need to be carefully selected; for example, clustering coefficient is found to be weakly correlated with resilience performance compared to other metrics of network connectivity (due to the grid-like structures of WDSs). Topological attribute metrics alone are not sufficient to guide the design of resilient WDSs and key details such as the location of water sources also need to be considered.

Performance Evaluation of Water Distribution Systems and Asset Management

Abstract Water distribution systems (WDS) are among the most critical civil infrastructure systems. A reliable and safe water supply is essential for the prosperity and continued well-being of soci...

Estimation of Leakage Ratio Using Principal Component Analysis and Artificial Neural Network in Water Distribution Systems

Leaks in a water distribution network (WDS) constitute losses of water supply caused by pipeline failure, operational loss, and physical factors. This has raised the need for studies on the factors affecting the leakage ratio and estimation of leakage volume in a water supply system. In this study, principal component analysis (PCA) and artificial neural network (ANN) were used to estimate the volume of water leakage in a WDS. For the study, six main effective parameters were selected and standardized data obtained through the Z-score method. The PCA-ANN model was devised and the leakage ratio was estimated. An accuracy assessment was performed to compare the measured leakage ratio to that of the simulated model. The results showed that the PCA-ANN method was more accurate for estimating the leakage ratio than a single ANN simulation. In addition, the estimation results differed according to the number of neurons in the ANN model’s hidden layers. In this study, an ANN with multiple hidden layers was found to be the best method for estimating the leakage ratio with 12–12 neurons. This suggested approaches to improve the accuracy of leakage ratio estimation, as well as a scientific approach toward the sustainable management of water distribution systems.

Management Index for the Decision Making of Priority of the Improvement in Water Distribution System

In this study, management indexes have been developed for the decision of priority of improvement in water distribution system. And the safety was estimated by management indexes for the real water distribution system. First of all, unsteady analysis has been performed and results were used for the reliability analysis. Reliability model is difficult to be used for the management of water distribution system since it contains so many steps. Therefore, management indexes such as pipe index of thickness, junction index of water usage, junction index of hydrant, pipe index of service year, junction index of hydraulic pressure, pipe index of accident history have been developed to estimate the safety of water distribution system. Management indexes were used for the estimations of safety and it was able to find the weakest area of water distribution system. Keywords: Junction Index, Management Index, Pipe Index, Water Distribution System

Simplified Approach to Water Distribution System Management via Identification of a Primary Network

This is the author accepted manuscript. The final version is available from American Society of Civil Engineers via the DOI in this record.

Editorial: Efficient water systems management

This special issue of Journal of Hydroinformatics presents a collection of papers initially presented at the 2nd EWaS International Conference ‘Efficient & Sustainable Water Systems toward Worth Living Development’. The conference was held on June 1–4, 2016, in Platanias/Chania, Crete, Greece (http://www.ewas2.tuc.gr/). The conference was co-organized by the University of Thessaly/Civil Engineering Department and the Technical University of Crete/School of Environmental Engineering (Co-chairmen: V. Kanakoudis – University of Thessaly, G. Karatzas – Technical University of Crete, vice chairman: E. Keramaris – University of Thessaly). The EWaS series of conferences started in 2013, when the 1st EWaS Conference was held in Thessaloniki. The 2nd EWaS International Conference highlighted the need to improve the efficiency and sustainability of water systems in a changing and fragile environment, especially under the frustrating economic conditions encountered today. Water scarcity and climate change are both considered today as the main causes of water-related problems. Moreover, it is estimated that 20–40% of Europe's available drinking water is being wasted through real (physical) losses occurring along the supply systems. This results in inefficient use of water and energy resources as well as negative economic, technical, social and environmental impacts. Efficient and sustainable management of water distribution systems asks for advanced tools and strategies for their analysis, monitoring, planning and operation. In this context, the integration with ICT innovations in the water sector offers new opportunities for water distribution systems management in urban areas, while exploiting the smart water networks paradigm. The current special issue of Journal of Hydroinformatics was guest-edited by Associate Professor Vasilis Kanakoudis (University of Thessaly, Volos, Greece) and Professor Marco Franchini (University of Ferrara, Italy). The papers included in this special issue are based on the initial presentations at the conference. However, they have been extended (by at least 50%) and revised, having gone through …