scholarly journals Probabilistic Minimum Night Flow Estimation in Water Distribution Networks and Comparison with the Water Balance Approach: Large-Scale Application to the City Center of Patras in Western Greece

Water ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 98
Author(s):  
Athanasios V. Serafeim ◽  
George Kokosalakis ◽  
Roberto Deidda ◽  
Irene Karathanasi ◽  
Andreas Langousis

Quantification of water losses (WL) in water distribution networks (WDNs) is a crucial task towards the development of proper strategies to reduce them. Currently, WL estimation methods rely on semi-empirical assumptions and different implementation strategies that increase the uncertainty of the obtained estimates. In this work, we compare the effectiveness and robustness of two widely applied WL estimation approaches found in the international literature: (a) the water balance, or top-down, approach introduced by the International Water Association (IWA), and (b) the bottom-up or minimum night flow (MNF) approach, based on a recently proposed probabilistic MNF estimation method. In doing so, we use users’ consumption and flow-pressure data from the 4 largest pressure management areas (PMAs) of the WDN of the city of Patras (the third largest city in Greece), which consist of more than 200 km of pipeline, cover the entire city center of Patras, and serve approximately 58,000 consumers. The obtained results show that: (a) when MNF estimation is done in a rigorous statistical setting from high resolution flow-pressure timeseries, and (b) there is sufficient understanding of the consumption types and patterns during day and night hours, the two approaches effectively converge, allowing for more reliable estimation of the individual WL components. In addition, when high resolution flow-pressure timeseries are available at the inlets of PMAs, the suggested version of the bottom-up approach with probabilistic estimation of MNF should be preferred as less sensitive, while allowing for confidence interval estimation of the individual components of water losses and development of proper strategies to reduce them.

2017 ◽  
Vol 18 (1) ◽  
pp. 347-356 ◽  
Author(s):  
Miran Mastaller ◽  
Philipp Klingel

Abstract Establishing the water balance developed by the International Water Association (IWA) is a worldwide applied approach to determine and analyse water losses in water distribution systems (WDS). The water balance covers those parts of a WDS within the responsibility of the water utility. Water losses occurring ‘before’ a customer meter are at the expense of the utility, while water lost or wasted ‘after’ the meter is paid for by the customer. This applies to systems where customer metering is in place and/or consumption is charged according to the consumed volumes. However, many WDS in the world lack customer meters, are operated intermittently and apply flat-rate tariffs. In intermittent supplies, a considerable amount of water is lost or wasted within the private properties. The flat-rate tariff might not cover this amount or part of the amount. Thus, actual consumption and wastage should be separately quantified with respect to the utility's water reduction measures. Accepting the described conditions, the authors have developed an adaption of the IWA water balance and the methods to establish the balance. In this paper the application of the developed approach in an initially unmetered WDS with intermittent water supply in the city of Tiruvannamalai, India, is presented.


Author(s):  
А.В. Степакин ◽  
А.Н. Перегуда ◽  
С.Г. Зайцева ◽  
Д.А. Горбачев ◽  
М.Н. Сопыряев

Природный дефицит водных ресурсов в сочетании с высокой степенью износа систем водоснабжения обусловливает напряженную ситуацию с обеспечением питьевой водой в Крыму. За последние несколько лет для решения проблемы на региональном и федеральном уровне были разработаны и реализуются программы модернизации водного хозяйства полуострова. Одной из ключевых задач этих программ является снижение потерь воды, которые в настоящее время достигают 40–60%. Описан комплекс мероприятий, направленных на снижение потерь воды в г. Севастополе. Комплекс мер, разработанный в соответствии с международным опытом и российскими рекомендациями, учитывает существующее состояние системы водоснабжения Крыма. Мероприятия включают в себя создание современного комплекса управления сетями, зонирование водопроводной сети, регулирование давления, мониторинг и устранение утечек. По результатам анализа производственных показателей определено, что первоочередным мероприятием для Севастополя является внедрение современной системы акустического мониторинга на распределительных сетях, которая позволит эффективно обнаруживать скрытые утечки и сэкономить городу тысячи кубометров дефицитной питьевой воды. Описаны результаты пилотного проекта по обследованию 5 км водопроводных сетей системой акустического мониторинга. The natural scarcity of water resources coupled with a high degree of deterioration of water supply systems result in a tense situation with the drinking water supply in Crimea. Over the past few years, a number of programs of upgrading the peninsula's water industry have been developed and are being implemented in order to solve the problem at the regional and federal levels. One of the key objectives of these programs is to reduce water losses that currently reach 40–60%. A set of measures aimed at reducing water losses in Sebastopol is described. The set of measures developed in accordance with the international experience and Russian recommendations takes into account the current condition of the Crimean water supply system. The activities include designing an advanced network management complex, zoning of the water supply network, pressure regulation, monitoring and elimination of leaks. Based on the results of the analysis of the performance indicators, it was determined that the priority measure for Sebastopol was the introduction of an advanced acoustic monitoring system in the water distribution networks that would provide for detecting effectively latent leaks and saving the city thousands of cubic meters of scarce drinking water. The results of a pilot project on the inspection of 5 km of the water supply networks using the acoustic monitoring system are described.


2010 ◽  
Vol 1278 ◽  
Author(s):  
V. Tzatchkov ◽  
M. P. Hansen ◽  
H. Ramírez

AbstractIn Mexico City, one of the largest cities in the world, large losses occur in the drinking water distribution system, mainly due to the age of the pipes and the type of materials used in water delivery to the end user. In the past, most of the water distribution networks in the city were built with asbestos-cement pipes. Currently, policies dictate that they be replaced by polyethylene pipes. While the size of the city leads to limited financial resources, it is important to prioritize pipe replacement; therefore, a practical approach based on Deterioration Point Allocation (DPA) is proposed to define the priority level. In the next set of factors, each is represented by appropriate indicators:1. Failures in pipes and service connectionsa. Number of failures (leaks) in pipes repaired in one year for every 100 km of pipeline.b. Number of failures (leaks) repaired in one year per 1000 service connections.c. Spatial concentration of failures (leaks) in a pipe2. Annual pipe and service connections rehabilitation or replacement level per year.3. Operating parameters of the network: intermittent water supply, water pressure, and water losses4. Deterioration status of pipes and service connections5. Land subsidenceA score and a weight are assigned to each factor. The score depends on the values of the indicator, and the weight on the relative importance of the factor. The final score is used to prioritize the replacement and it is calculated by adding up the scores of each factor.Considering that available information is incomplete and unstructured, two levels of use are proposed: basic (with available data, using MS Excel) and advanced (using a GIS).


2017 ◽  
Vol 7 (3) ◽  
pp. 396-406 ◽  
Author(s):  
Miran Mastaller ◽  
Philipp Klingel

The International Water Association water balance is an approach applied worldwide for determining and analysing water losses in water distribution systems (WDS) up to the point of customer metering. Thus, water losses occurring ‘before’ a customer meter are at the expenses of the water utility while water lost or wasted ‘after’ the meter is paid for by the customer. This applies to systems where customer metering is in place and/or consumption is charged according to the consumed volumes. However, many WDS in the world lack customer meters, are operated intermittently and a considerable amount of water is lost or wasted within the private property, e.g. by overflows of private tanks. The flat-rate tariff applied might not cover this amount or part of the amount. Thus, actual consumption and wastage should be separately quantified or estimated with respect to the utility's water reduction measures and the calculation of revenue water. This paper presents a water balance approach adapted to WDS which are operated intermittently, lack customer metering and charge flat-rate tariffs as well as a methodology for establishing the balance. The application is demonstrated for a district metered area of the city of Tiruvannamalai, India.


2021 ◽  
Author(s):  
Athanasios V. Serafeim ◽  
Irene Karathanasi ◽  
George Kokosalakis ◽  
Roberto Deidda ◽  
Andreas Langousis

<p><strong>Abstract</strong></p><p>In the present work we develop and test a non-parametric statistical methodology to obtain point estimates of Minimum Night Flow (MNF) in Water Distribution Networks (WDNs). The methodology constitutes a simplified version of the approach of Serafeim et al. (2021) for confidence interval estimation of background losses in WDNs, that simultaneously analyzes all night flow measurements, producing robust estimates independent of the nominal resolution of the available data.</p><p>In addition to being simpler to apply and computationally more efficient, the developed method can be applied to any WDN independent of its size, age and overall condition, its  specific geometric characteristics (intensity of altimetry, average diameter etc.), inlet/operating pressures, and the nominal resolution of the flow data.</p><p>The effectiveness of the method is tested via a large-scale application to the WDN of the City of Patras in western Greece, which consists of 79 Pressure Management Areas (PMAs) with more than 700 km of pipeline grid. To do so, we use flow data at 1 min temporal resolution, provided by the Municipal Enterprise of Water Supply and Sewerage of the City of Patras, for the 4-month winter period from 01 November 2018 – 28 February 2019, which are progressively averaged to coarser temporal resolutions, in an effort to test the sensitivity of the developed method to the nominal resolution of the data.  </p><p>The obtained point estimates of MNF are assessed on the basis of the confidence intervals obtained by the approach of Serafeim et al. (2021), highlighting the accuracy and robustness of a simple non-parametric approach in providing MNF point estimates at a minimum of effort.</p><p><strong>Acknowledgements</strong></p><p>The research work was supported by the Hellenic Foundation for Research and Innovation (H.F.R.I.) under the “First Call for H.F.R.I. Research Projects to support Faculty members and Researchers and the procurement of high-cost research equipment grant” (Project Number: 1162).</p><p><strong>References</strong></p><p>Serafeim, A.V., G. Kokosalakis, R. Deidda, I. Karathanasi and A. Langousis, (2021) Probabilistic Estimation of Minimum Night Flow in Water Distribution Networks: Large-scale Application to the City of Patras in Western Greece (submitted).</p>


10.29007/gvnz ◽  
2018 ◽  
Author(s):  
Armando Di Nardo ◽  
Michele Di Natale ◽  
Anna Di Mauro ◽  
Eva Martínez Díaz ◽  
Jose Antonio Blázquez Garcia ◽  
...  

The recent development and applications of social network theory in many fields of engineering (electricity, gas, transport, water, etc.) allows both the understanding of networks and to improve their management. Social network theory coupled to the availability of real time data and big data analysis techniques can change drastically the traditional approaches to manage civil networks. Recently, some authors are working to apply this novel approach, based on social network theory, on the water distribution networks using: a) graph partitioning algorithms to define optimal district meter areas both for water losses identification and for water network protection, b) innovative topological, energy and hydraulic indices to analyze performance; and c) GIS (Geographical Information System) to provide a more effective display of results and to improve network behavior in specific operational conditions. In this paper, a novel release 3.5 of SWANP software, that implements all these features, was tested on a real large water network in Alcalá de Henares, Spain.


2021 ◽  
Vol 55 (5) ◽  
pp. 1046-1069
Author(s):  
Nir Fulman ◽  
Itzhak Benenson

We propose an approximation method for estimating the probability [Formula: see text] of searching for on-street parking longer than time [Formula: see text] from the start of a parking search near a given destination [Formula: see text] based on high-resolution maps of parking demand and supply in a city. We verify the method by comparing its outcomes to the estimates obtained with an agent-based simulation model of on-street parking search. As a practical example, we construct maps of cruising time for the Israeli city of Bat Yam and demonstrate that, despite the low overall demand-to-supply ratio of 0.65, excessive demand in the city center results in a significant share of parking searches that last longer than 5 or even 10 minutes. We discuss the application of the proposed approach for urban planning.


Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3446
Author(s):  
Martin Oberascher ◽  
Michael Möderl ◽  
Robert Sitzenfrei

Water losses in water distribution networks (WDNs) are unavoidable. Water losses are evaluated based on performance indicators (PIs) and used for future recommendations for network operators to take measures against water losses. However, these evaluations primarily focus on large and medium sized WDN and do not deal with the challenges of small WDNs (e.g., technical, and financial limitations, missing data). Therefore, an appropriate water loss management is a major challenge for operators in the federal state of Tyrol (Austria) due to the high number of small WDNs, e.g., low income in combination with long network lengths. In this regard, this work specifies and discusses state funding in Austria to support network operators to reduce water losses. To assess the impacts on management strategies, 40 WDNs, supplying 200 to 16,000 inhabitants, are investigated in detail. As the comparison of different PIs shows, a volume related PI (e.g., water loss volume divided by total water demand) is recommend as the decision criterion for local authorities due to minimal efforts and its easy calculation. Moreover, public funding helps to significantly reduce water losses in individual systems, but countermeasures should be different for small and larger WDNs. For example, leakage detection campaigns and rehabilitation planning based on pipe age should be established in future for larger WDNs in Tyrol. In contrast, an online flow metering system to monitor system inflows is suggested for small WDNs. Based on measurement data, leakages and burst can be detected and repaired swiftly.


2014 ◽  
Vol 16 (6) ◽  
pp. 1280-1301 ◽  
Author(s):  
Robert Wright ◽  
Ivan Stoianov ◽  
Panos Parpas ◽  
Kevin Henderson ◽  
John King

This paper presents a novel concept of adaptive water distribution networks with dynamically reconfigurable topology for optimal pressure control, leakage management and improved system resilience. The implementation of District Meter Areas (DMAs) has greatly assisted water utilities in reducing leakage. DMAs segregate water networks into small areas, the flow in and out of each area is monitored and thresholds are derived from the minimum night flow to trigger the leak localization. A major drawback of the DMA approach is the reduced redundancy in network connectivity which has a severe impact on network resilience, incident management and water quality deterioration. The presented approach for adaptively reconfigurable networks integrates the benefits of DMAs for managing leakage with the advantages of large-scale looped networks for increased redundancy in connectivity, reliability and resilience. Self-powered multi-function network controllers are designed and integrated with novel telemetry tools for high-speed time-synchronized monitoring of the dynamic hydraulic conditions. A computationally efficient and robust optimization method based on sequential convex programming is developed and applied for the dynamic topology reconfiguration and pressure control of water distribution networks. An investigation is carried out using an operational network to evaluate the implementation and benefits of the proposed method.


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