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An accurate estimation of leakages in water distribution networks is of primary importance for the definition of strategies aimed at ensuring an efficient management of water resources and avoiding water waste. However, in the case of methods based on water balance—such as the Minimum Night Flow method—inaccurate assessment of the minimum night consumption (MNC), e.g. the assumption of fixed MNC values from the literature, can heavily mislead the quantification of leakage level. This study aims at providing insights into the variability of MNC and the related drivers. In greater detail, hourly water consumption data of approximately 200 users are collected over a period of two years and subjected to a multi-phase methodology to obtain a detailed characterization of MNC, with and without considering the users affected by post-meter leakages. The study demonstrates that factors such as seasonality or the presence of post-meter leakages may strongly impact the MNC—the values of which can significantly deviate from the literature references—and thus lead to significant misestimation of network leakages in water systems. Highlights: A methodology for the statistical analysis of minimum night consumption (MNC) based on the daily water-consumption profiles at the user level is proposed. The methodology is applied to hourly-resolution water-consumption data collected over two years in a sample of over 200 users. Occupancy rate, seasonality, and presence of post-meter leakages affect MNC statistics. [ABSTRACT FROM AUTHOR]

Intermittent water distribution systems supply over a billion people worldwide, a number expected to increase due to water scarcity, population growth, and urbanization. This study proposes a multiphase methodology for the definition of strategies (i.e., investments and controls) for the rehabilitation of complex intermittent systems over multiple-year periods. The multiphase methodology was developed in the context of the Battle of Intermittent Water Supply (BIWS) and is based on the use of EPANET 2.2 software for hydraulic modeling in combination with MATLAB version 2019a programming software. First, the hydraulic analysis of the deteriorated network is conducted to localize its main vulnerabilities. Second, multiple intervention strategies for network initial layout and subsequent rehabilitation (i.e., control modifications and investments) are identified considering different subsets of decision variables in turn. The effectiveness of each defined rehabilitation strategy is then quantified by means of a group of indicators reflecting the multiobjective nature of the problem. Finally, the best solution among all the defined rehabilitation strategies is identified and iteratively revised in order to further enhance its effectiveness on the deteriorated system. The application of the proposed rehabilitation method to the realistic and complex water distribution network considered as a case study in the BIWS—consisting of nearly 3,000 nodes—allowed obtaining an effective intervention solution for the reduction in the critical issues related to the system, ensuring 97% of users would be continuously supplied at the end of the rehabilitation period. [ABSTRACT FROM AUTHOR]

This paper presents the results of the monitoring and analysis of the dynamic behaviour of the Gorino Ferrarese (Ferrara, Italy) water distribution system. The network is subjected to ordinary operational conditions, (i.e. no manoeuvres on pumps or valves are considered), the aim being to show that user demand may generate frequent and not negligible pressure variations. Pressure and discharge were monitored for two days in different sections of the network. The dynamic behaviour of the system is then characterized by analysing the pressure changes at the measurement sections in the time and frequency domains. Such analyses highlight that pressure signals are characterized by long-term changes (low-frequency) on which shorter period (high-frequency) ones overlap. Long-term oscillations show a similar trend at all measurement sections and are characterized by certain dominant frequencies, linked to the topological and mechanical characteristics of the network. Instead, high-frequency pressure fluctuations related to user activity vary in amplitude both spatially and temporally. [ABSTRACT FROM AUTHOR]