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Source water protection (SWP) is the most important step in the implementation of a multi-barrier approach that ensures cost-effective delivery of safe drinking water. However, implementing SWP strategies can be a challenging task owing to technical and administrative issues. Decision support tools for effective implementation of SWP strategies can be very helpful that may lead to saving time and resources. This paper critically reviews different SWP strategies available for surface waters and also discusses various formulations for water quality assessment at the source. Source water quality regulations in Canada and other jurisdictions around the world are also discussed. Stormwater management ponds, vegetated filter strips, pollution control by effective agricultural practice (e.g., cover crop and crop rotation) and fencing are found to be frequently mentioned in those regulations. These strategies are discussed in details in terms of their key features to achieve the highest possible removal efficiencies for selected water quality parameters. Finally, a conceptual model is proposed to evaluate water quality changes at the source based on selected source water protection strategies. The model uses SWP strategies as a means to reduce possible pollutants in the source water. It also utilizes simple mass balance equations (dilution) to estimate the concentrations in the receiving water bodies and does not consider physicochemical and other reactions. A surrogate measure, water quality index (WQI), based on selected water quality parameters, is used for the assessment of source water quality. Key words: source water protection strategy, water quality index, low-impact development (LID), best management practices (BMP), stormwater management, conceptual model, fuzzy-based methods. La protection des sources d'eau (<< SWP >>) constitue l'etape la plus importante dans la mise en oeuvre d'une approche a barrieres multiples pour assurer la livraison d'eau potable fiable a un cout efficace. Cependant, la mise en place de strategies de protection des sources d'eau peut constituer un defi impliquant des enjeux techniques et administratifs. Des outils d'aide a la decision pour la mise en place efficace de strategies de protection des SWP peuvent s'averer fort utiles pour sauver du temps et des ressources. Les auteurs revoient, de facon critique, differentes strategies de protection des sources d'eau SWP disponibles pour les eaux de surface et discutent diverses formulations pour revaluation de la qualite de l'eau a la source. Les reglementations sur la qualite; des sources d'eau au Canada et dans d'autres juridictions a travers le monde sont aussi analysees. Les bassins pour la gestion des eaux des tempestes, les bandes filtrantes vegetales, le controle de la pollution par des pratiques agricoles efficaces (e.g., culture de couverture et rotation de cultures) et l'utilisation de cloture constituent des strategies frequemment citees dans ces reglementations. Ces strategies sont discutees en detail en ce qui concerne leurs caracteristiques fondamentales pour aboutir aux niveaux d'efficacite les plus eleves possibles relatifs a l'elimination des paramtetres de qualite d'eau (<< polluants >>) selectionnes. Enfin, les auteurs proposent un modele conceptuel pour evaluer les changements de la qualite de l'eau a la source, base sur les strategies de protection des sources d'eau selectionnees. Le modele utilise les strategies de protection des SWP comme un moyen pour reduire les charges possibles de polluants vers la source d'eau. Il utilise aussi des equations simples de bilan de masse (<< dilution >>) pour estimer les concentrations de polluants au niveau des plans d'eau recepteurs; il ne considere pas les reactions physico-chimiques ou autres. Une mesure de substitution, un indice de qualite d'eau (<< WQI >>), base sur les paramtetres de qualite; d'eau choisis, est utiliseee pour revaluation de la qualite des sources d'eau. Mots-cles: strategie de protection des sources d'eau, index de qualite; de l'eau, developpement a faible impact (LID), meilleures pratiques gestion (BMPs), amenagement de l'eau des tempetes, modele conceptuel, methodes basees sur la logique floue. [Traduit par la Redaction], 1. Introduction The goal of source water protection (SWP) strategies is to save the source water from a potential pollution source. Though source water refers to both ground and surface [...]

For the last few decades, concerns have repeatedly been raised about deteriorating water mains in Canada. Small to medium sized water utilities are generally impacted more due to lack of technical and financial resources. This paper presents a user-friendly life cycle cost (LCC) analysis-based decision support tool to help these utility managers to prioritize water mains rehabilitation or replacement (R/R) strategies. The deterioration curves for water mains of different materials and sizes have been developed based on their likelihood of failure. The proposed model is implemented for the water supply network of City of Kelowna (Canada). It compares the costs of various R/R scenarios for each pipe over its life cycle and suggests the most cost-effective decision to the managers to efficiently allocate their limited resources. [ABSTRACT FROM AUTHOR]

Online drinking water quality monitoring technologies have made significant progress for source water surveillance and water treatment plant operation. The use of these technologies in the distribution system has not been favorable due to the high costs associated with installation, maintenance, and calibration of a large distributed array of monitoring sensors. This has led to a search for newer technologies that can be economically deployed on a large scale. This paper includes a brief description of important parameters for drinking water and current available technologies used in the field. The paper also provides a thorough review of the advances in sensor technology for measurement of common water quality parameters (pH, turbidity, free chlorine, dissolved oxygen, and conductivity) in drinking water distribution systems. [ABSTRACT FROM PUBLISHER]

All over the world water mains are under increasing threat due to aging, aggressive environmental factors, operational factors and inadequate maintenance. Extensive maintenance, repair and rehabilitation practices, or replacement of water mains are required to ensure an acceptable performance of water supply systems. Investment deficit for water system maintenance and rehabilitation has been estimated in billions. Small to medium sized water utilities are generally impacted more because of limited financial resources and lack of technical expertise. However, water mains integrity is of primary interest due to potential adverse consequences related to public health, safety, and heavy financial liabilities in case of a failure. This paper presents a user-friendly decision support tool to help managers of these water utilities to prioritize maintenance, repair, and replacement (M/R/R) strategies for water mains. This paper proposes a risk index approach which aggregates the water mains vulnerability and associated failure consequences. The developed tool can help decision-makers to rank the water mains and help to prioritize M/R/R strategies. The results have been integrated with a geographic information system that will allow a decision-maker to visualize the vulnerable zones within the network. The City of Kelowna water network is used to demonstrate the proposed approach. [ABSTRACT FROM AUTHOR]

Loss of water due to leakage is a common phenomenon observed in all water distribution systems. However, the water loss can be reduced to an acceptable limit by improved understanding of leakage mechanisms and pathways, and the influencing factors that lead to leakage. This study proposes a methodology to estimate leakage potential (LP) in a water distribution system (WDS). The study has identified various factors which are directly and/or indirectly associated with LP in a WDS. The research has defined a selected set of influencing factors as fuzzy variables and has developed a fuzzy rule-based (FRB) model using Mamdani inferencing algorithm. The impact of influencing factors varies under different operating pressure, therefore a generalized methodology has been proposed. The proposed methodology has been implemented for a real WDS in Bangkok (Thailand). To evaluate the impacts of uncertainties of influencing factors on LP, Monte Carlo simulation-based sensitivity analysis has been carried out. It has been concluded that the operating system pressure and age of the network are the two most important factors that contribute to LP of a WDS. The proposed model will help water utility managers to prioritize their network rehabilitation strategies and to establishing an efficient active leakage control program. [ABSTRACT FROM AUTHOR]

Loss of water due to leakage is a common phenomenon observed practically in all water distribution systems (WDS). However, the leakage volume can be reduced significantly if the occurrence of leakage is detected within minimal time after its occurrence. This paper proposes a novel methodology to detect and diagnose leakage in WDS. In the proposed methodology, a fuzzy-based algorithm has been employed that incorporates various uncertainties into different WDS parameters such as roughness, nodal demands, and water reservoir levels. Monitored pressure in different nodes and flow in different pipes have been used to estimate the degree of membership of leakage and its severity in terms of index of leakage propensity (ILP). Based on the degrees of leakage memberships and the ILPs, the location of the nearest leaky node or leaky pipe has been identified. To demonstrate the effectiveness of the proposed methodology, a small distribution network was investigated which showed very encouraging results. The proposed methodology has a significant potential to help water utility managers to detect and locate leakage in WDS within a minimal time after its occurrence and can help to prioritise leakage management strategies. [ABSTRACT FROM AUTHOR]

This paper explores the application of the quality function deployment (QFD) approach to identify and prioritize factors to reconcile 'actual' risk with 'perceived' risk for drinking water in a distribution network. Consumers' complaints (regarding water odour, taste, colour and other problems) and consumers' perception about water safety are used to define customers' requirements (aka 'whats'). Twelve water quality parameters and distribution network properties (e.g. turbidity, pipe breaks) are used as indicators for drinking water quality -- the product characteristics (aka 'hows'). Correlations between 'whats' and 'hows' are established using data obtained from a case study. Opinions of experts in drinking water and consumers are used to define correlations between the 'what' 'microbial safety' and the 'hows'. The analytic hierarchy process allows prioritizing customer requirements. Three QFD-based methods are applied to prioritize factors affecting water quality in a distribution network. The proposed approach is demonstrated through a case study of a water distribution network in Quebec City (Canada). Results show that the factors that primarily affect customers' requirements include free residual chlorine, turbidity and trihalomethanes. Sensitivity analyses using three scenarios confirm the robustness of the proposed approach. Utility managers must take action, especially concerning these product characteristics, to satisfy customers' requirements. [ABSTRACT FROM AUTHOR]

This work investigates the problem of combining deficient evidence for the purpose of quality assessment. The main focus of the work is modeling vagueness, ambiguity, and local nonspecificity in information within a unified approach. We introduce an extended fuzzy Dempster-Shafer scheme based on the simultaneous use of fuzzy interval-grade and interval-valued belief degree (IGIB). The latter facilitates modeling of uncertainties in terms of local ignorance associated with expert knowledge, whereas the former allows for handling the lack of information on belief degree assignments. Also, generalized fuzzy sets can be readily transformed into the proposed fuzzy IGIB structure. The reasoning for quality assessment is performed by solving nonlinear optimization problems on fuzzy Dempster-Shafer paradigm for the fuzzy IGIB structure. The application of the proposed inference method is investigated by designing a reasoning scheme for water quality monitoring and validated through the experimental data available for different sampling points in a water distribution network. © 2011 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Selecting and prioritizing monitoring locations (zones) in a water distribution network (DN) involves complex decision-making that warrants the use of risk-based decision-making. This paper couples the concept of risk with fuzzy sets and provides a simple approach to prioritizing monitoring locations in a DN. An index-based approach is proposed to estimate vulnerability, sensitivity and risk indices at a given DN location. The approach is based on fuzzy-based techniques that include fuzzy synthetic evaluation and fuzzy rule-base. Two types of analyses (deterministic and probabilistic) are used to demonstrate the proposed approach for a DN in Quebec City (Canada). Fifteen 'input factors' related to structural integrity, hydraulics, water quality and consumer sensitivity are used in the analyses. Based on the risk index results, the DN is divided into two parts. Sensitivity analysis results reveal that four factors, including two sensitivity factors (i.e. % population < 5 and > 75 yr) and two vulnerability factors (free residual chlorine and pipe breaks), explain 85% of the risk index variability. The usefulness of the proposed approach is demonstrated and strategies to improve the model are discussed. [ABSTRACT FROM AUTHOR]