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Copyright of Journal of Water Resources / Recursos Hídricos is the property of Associacao Portuguesa dos Recursos Hidricos and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper describes the development of an integrated approach for water pipe network calibration and lea quantification. The proposed approach provides a practical procedure that merges field measurements and mathematical modeling for leak quantification and network calibration. The use of Evolutionary Algorithms (EA) using both Genetic Algorithms (GA) and Shuffled Complex Evolution – University of Arizona (SCE-UA) to calculate the pinpointed leak outflows well as to identify any faulty meters. Also, by treating pinpointed physical leaks as junction points, the model, via EPAnet connection, calibrates the network and calculates their demands (which is equivalent to physical losses) and estimating pipes roughness factor (CHW) for better network calibration. Besides, throughout the process, the developed model uses GA and SCE-UA but departs from traditional use in using floating-point representations and introducing a new self-adaptive constraint handling function, which yields optimal results in fewer generations (model runs). Two pilot networks are selected, a well-known hypothetical network (Hanoi network) to present the general mathematical model, while a real network (Faisal city network) is used to test the integrated approach. The model integrates EPAnet for the required hydraulic modeling during the simulation and GIS for input data integration and output representation during the whole procedure. The results prove the approach's accuracy and efficiency. [ABSTRACT FROM AUTHOR]

Water loss is defined as the volume of water supplied to a system minus the volume of permitted usage. Water losses contain real and apparent losses. Real loss occupies pipelines in the distribution network, junctions, fittings, and water tanks. Apparent loss is contained within the metering devices, such as input, output and subscriber meters and, of course, illegal uses. Apparent losses are also identified as managerial losses. The aim of this study is to devise a strategy to prevent water losses in the Diyarbakir drinking water network by developing an efficient hydraulics method. To achieve this aim, in the four provinces in Diyarbakir (Sur, Baglar, Yenisehir and Kayapinar) parameters such as pipeline quantities, population, subscriber numbers and subscriber types are combined, to develop a new method for the selected regions using SCADA (Supervisory Control and Data Acquisition), SIS (Subscriber Information System) and Geographical Information System (GIS). In this study, Martyrs -1 (M-l) and Martyrs 2 (M-2) have been selected as pilot regions. To prevent water losses in Diyarbakir drinking water network some effective recommendations are suggested. [ABSTRACT FROM AUTHOR]

Copyright of Revista Ambiente e Água is the property of Revista Ambiente e Agua and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A very common problem in distribution systems is water leakage, which can be reduced by pressure management. The objective of this study was to evaluate the reduction of water leakage by optimizing the pressure using pressure reducing valves (PRV). The corresponding hydraulic model of a real distribution network was developed using the EPANET software. After the hydraulic model was calibrated and validated, the analysis of the pressure in the nodes, the velocity in the pipes, through the technical performance indicators (TPI) was performed, in addition, the leakages were quantified. The initial results indicated the need to optimize the pressure, nodes with excessive pressures were found in the lower part of the network. WaterNetGen was used as an extension of EPANET software to model leakages based on pressure after determining the leakage coefficient and considering the installation of two PRVs. The results allowed optimizing the appropriate pressure in 30.83% of the nodes and minimizing leakages in 31.65%. In turn, the simulation assuming the installation of two PRVs determined that the TPI would increase from 79.81% to 97.45%. The focus of this study is recommended to the companies that supply drinking water as a support tool for planning to reduce leakages. [ABSTRACT FROM AUTHOR]

Managing Non-Revenue Water (NRW) in water distribution systems has become more crucial for sustainable management of water resources. This study is aimed to provide insights into research activities and tendencies of the NRW management. For this purpose, a bibliometric analysis was carried out based on the Science Citation Index Expanded from the Web of Science (WoS). A set of key terms related to NRW management was used to retrieve publications from the database of WoS. A quantitative analysis of publications including leading countries, research tendencies and hotspots of NRW management were presented in this study. The first publication indexed in WoS database was published in 1976 and the number of publications showed an increasing trend starting from 2009. Italy was the most productive country for number of total articles and the most collaborated country for retrieved publications. A summary of the most frequently used key terms obtained from words in paper title analysis, author keyword analysis and abstract analysis provided current research tendencies and hotspots. Detecting and locating physical losses and pressure management for reduction of physical losses were found to be research tendencies of NRW management studies. [ABSTRACT FROM AUTHOR]

Hydro-turbines are widely used in small water energy production plants in order to turn water kinetic energy to electricity. PATs (Pumps working As Turbines) are micro-turbines (small sized compared to the usual ones) working on “reverse mode” compared to the usual pumps. Installation of a PAT aims to produce energy along with managing/keeping the downstream pressure to a desired level. PRVs (Pressure Reducing Valves) are used to decrease pressure aiming to reduce water losses linked to this extra pressure potential available. The current study focuses on the possibility to replace a PRV with a PAT in a real water distribution network checking its ability to reduce pressure to acceptable levels as well as produce significant amount of energy. The water distribution system of Kozani city (in Northern Greece) is used as the case study network. Various operating scenarios regarding the exact location of the PAT were checked in the network's calibrated hydraulic model with interesting results. [ABSTRACT FROM AUTHOR]

High leakage levels in the water supply network of the city of Patras is one of the most important issues, which must be dealt by the Municipal Enterprise of Water Supply and Sewerage of Patras (DEYAP). DEYAP provides services to the 3rd largest city of Greece, Patras and the environs, covering a service area of 333 km 2 and a population of approximately 240.000. It is responsible for the Operation and Maintenance of the Water Supply system comprising a network of 1000km of water pipes and 134.000 customer water meters. The Non-Revenue Water is approximately 55% of the System Input Volume from which a significant proportion is estimated as being physical losses. Until now the approach to leakage control is a passive one, whereby leaks are repaired only when they become visible. However, DEYAP is developing a permanent Leakage Control System according to the International Water Association (IWA) methodology. For the implementation of this system a project is currently under construction, including the Establishment of DMAs, Pressure Management, Creation of a GIS-based decision support system, Aggregation of various operational Databases through development of an intelligent reporting software with data warehouse techniques, Procurement of Leak detection equipment and training DEYAP's personnel in the operation of Pressure Management systems. [ABSTRACT FROM AUTHOR]

Water loss control and reduction is a major issue in Water Distribution Network (WDN) management worldwide. In many WDNs, the infrastructure monitoring in terms of flow/pressure measurements through the network, is not implemented yet and only few data (e.g. measurement of WDN inflow) are available to estimate the current leakage rate. Cheap and easily applicable procedures are needed to estimate current water losses in WDNs aimed at understanding the actual magnitude of the phenomenon and planning interventions. This work presents a simple methodology, inspired by the analysis of WDN inflow data records collected in several real water distribution networks, which permits to assess leakages based on the seasonal fluctuation of water consumptions. The methodology is tested on two synthetic case studies based on the Apulian WDN, which hydraulic status is simulated by an advanced WDN model that includes a realistic pressure-dependent background leakage model. The analyses of case studies verifies the effectiveness of the methodology under fully controlled WDN configurations (e.g. neglecting measurement inaccuracies that might happen in real WDN and/or possible alterations of asset conditions over the analyzed period). The resulting estimates of leakages proved to be accurate under the analyzed condition, thus making the methodology promising for next applications on real WDNs. [ABSTRACT FROM AUTHOR]

In the last decades, a growing attention on energy saving associated with water resources usage and leakages reduction has been recorded at both national and international level. Scientific research has focused on implementation of several methodologies aimed at the understanding of energy transformation processes occurring in the integrated water system. The main concern is then identifying energy impacts associated to each macro-area of integrated water system, such as collection, treatment and distribution, and analysing the potential interactions between them. Unfortunately, only overall energy consumptions are usually available at national level. The main objective of the paper is to present a decision support tool, developed in the framework of the ALADIN project, able to analysing the water and energy balance in the integrated water service. In order to achieve a sustainable use of water resources, the tool allows an assessment of the energy impact of different macro - areas of integrated water system. Moreover, each macro - area can be treated as an element able to share energy with other elements, aiming to obtain an energy saving on the whole integrated water system. In this way, the decision support tool could suggest efficient solutions, according to the operator objectives,with regard to energy and water losses management. Therefore, the tool could provide guidelines for choosing the best management solutions, depending on the particular analysed system, and allow, at the same time, the energy and water resources saving. The proposed tool was applied to a complex water supply system, the Favara di Burgiosystem (Sicily, Italy) in order to show its reliability. [ABSTRACT FROM AUTHOR]

The application of a novel energy auditing scheme in a real water supply system and its sub-systems to determine major sources of energy inefficiency is presented. This scheme has been consolidated in the Portuguese National Initiative for the management of water-energy losses ( www.iperdas.org ). Within this initiative, 17 water utilities have carried out energy audits following a two-step procedure: (i) simplified energy auditing and calculation of efficiency metrics for the global system and for sub-systems and (ii) detailed energy auditing for critical sub-systems. The case-study of Águas do Sado water utility is presented to illustrate the application of this approach. This system has 25% of non-revenue waterand consumes 5.5 GWh per year, which is approximately twice the minimum energy required. The analysis of therespective 17 sub-systems has shown that the major inefficiencies are due to topography constraints, to water losses and to the lack of intermediate service pressure levels. [ABSTRACT FROM AUTHOR]

The determination of the optimal location and settings of PRV is an operational problem that water utilities must deal with in order to reduce the real losses that are inherent to their water distribution system. In this research, a multi-objective optimization approach was developed to provide an optimal solution for the addressed problem, using the well-known metaheuristic algorithm NSGA-II and including the usage of hydraulic criteria to reduce the solution space, in order to enhance the performance of the procedure. The proposed methodology was tested using two different networks, which differ in their leakage configuration and the hydraulic parameters used for this modeling. [ABSTRACT FROM AUTHOR]

The experimental study of the effects of pressure on leakages in water distribution networks has been addressed by many authors in recent years. However, most works have been focused on pipes directly placed in atmosphere, and the real conditions of installation are neglected. In this paper, the early results of a new experimental campaign recently started at the Department of Civil, Architectural and Environmental Engineering of University of Naples Federico II are presented. The interaction of a HDPE pipe buried in a volcanic soil is investigated from both hydraulic and geotechnical point of view. [ABSTRACT FROM AUTHOR]

Abstract: The paper presents a multi-objective approach for the automatic partitioning of a water distribution network into District Metering Areas (DMAs). In the proposed methodology, both technical and economic issues are considered, including reduction of water leakages due to pressure management and energy production achievable through the use of turbines. The optimization approach is based on a clear explanation of the objective functions, whose structures are defined with the aim of providing full control to the decision-maker. Concepts from graph theory and cluster analysis methods are combined in a three-step algorithm, which can be easily implemented for software use. [Copyright &y& Elsevier]

Abstract: In a distribution water network, only a small part represents an economical input for the operator organisms and in some cities it has been estimated big losses in the network, according to the International Water Association (IWA). In water distribution network system most of them results of leaks which are presented in storage tanks, and home outlets (Real losses). The unauthorized and unquantified home outlets (Appaent losses) could represent most of physical losses into the water distribution network. In this paper is proposed a simple and economical methodology to quantify the apparent losses and generate a geographical information system (GIS). [Copyright &y& Elsevier]

The reduction of water losses is a crucial aspect to be addressed in Water Distribution Networks (WDNs) since they account for almost 50% of the water supply globally. To have a better figure of the involved water volumes, the District Metered Area (DMA) approach has been used in a WDN of a town located in the center of Italy (Osimo). In particular, a complete methodology for calculating and then detecting the water losses is described and applied using the end-users' water volumes consumptions obtained by inspecting water bills and the supplied water through on-field measurements. These values have been subsequently used to develop and calibrate a hydraulic model of the district under investigation through EPANET, thus allowing the WDN management to estimate both flow rates and pressures to assess the zones where smart meters have to be installed. Water losses have been controlled by monitoring the flow rates through smart meters with an innovative 868 MHz remote reading infrastructure, thus leading to 5,558.8 m3 of avoided water losses (12.5% less than the initial case) that corresponds to an energy reduction and an economic saving of 7,332 kWh and 1,857 € in the last three-month period of the year 2020, respectively. • The district metered area approach was used to reduce water leakages in WDNs. • On-field measurements of a WDN in Italy were performed to validate the method. • A numerical model was also built in EPANET® in order to resemble the analysed WDN. • Smart meters and a fixed infrastructure were used in the selected water district. • Energy (7.3 MWh) and (2 k€) economic savings in the last three month-period of 2020. [ABSTRACT FROM AUTHOR]

Abstract: The problem of leakage is complex and requires actions drawn from different aspects of water network management. Inadequate maintenance has serious consequences, both financial and environmental. This paper proposes a group decision-making model based on PROMETHEE V method to aim a leakage management strategy, which takes into account the points of view of four stakeholders, selecting feasible options, and considering the available budget as constraint. Thus, this strategy is the combination of options that will efficiently meet technical, socio-economic and environmental criteria to achieve sustainable development. [Copyright &y& Elsevier]

This paper presents a mathematical model for the numerical prediction of the performance of crossflow cooling towers. The mathematical model is based on the heat and mass transfer equations. The leading parameters are the Lewis number Le, the number of transfer units U, the percentage of water evaporation, the water losses and the tower efficiency. This model is used to predict the thermal behavior of six cooling towers located in the South of Tunisia. These towers are employed to decrease the temperature of geothermal water from 65°C to 34°C using a crossflow air. The total flow rate of water is 900 kg s−1 and that of dry air is 1840 kg s−1. Several experimental data have been collected on site, in order to adopt the mathematical model.The model has been used to predict the performance of cooling towers in terms of the meteorological conditions prevailing in the South of Tunisia. An optimal water loss quantity has been determined. On an annual basis, the actual water losses by evaporation represent 4% of the total water flow rate which correspond to 106 m3 year−1. This represents the annual consumption of 20 000 inhabitants. [Copyright &y& Elsevier]

• A combination of a water tank and continuous supply worsens the meter performance. • Higher intermittency levels improve the meter performance and reduce revenue losses. • Towards 24/7, meter replacement policy should recognize lower flows passing the meter. Intermittent supply is common worldwide. It triggers households with piped connection to adjust the supply scheme by the use of a water tank with a float valve (FV) at the entrance, which has a major influence on the water meter accuracy. This study investigated the impact of the water tank with a FV on the performance of water meters under intermittent and continuous supply conditions, using laboratory experiments, field measurements, and hydraulic modeling. Results revealed that the inflow rates into the water tank are consistently lower than the outflow rates of the tank. This will always be the case owing to the balancing mechanism of the tank. The flows that pass through the water meter represent the inflows into the tank. Therefore, higher metering errors and more apparent losses are expected for a combination of a water tank, FV, and continuous supply. Besides, different FV types have different hydraulic characteristics. Larger FVs with higher discharge rates tend to maintain the water level close to the full level in the tank and conferred longer periods of low flows, worse meter performance, and more apparent losses. For intermittent supply, results confirmed that higher intermittency levels lead to improved performance of water meters and reduce the apparent losses. This points to the complication in transformation from intermittent to continuous supply worldwide. In this case, water utilities should expect higher meter errors and more revenue losses unless the meter replacement policy recognises lower flows passing through the meter. [ABSTRACT FROM AUTHOR]