scholarly journals Spectral Analysis of Uncertainty in Water Age

10.29007/969c ◽  
2018 ◽  
Author(s):  
Mathias Braun ◽  
Olivier Piller ◽  
Jochen Deuerlein ◽  
Iraj Mortazavi ◽  
Angelo Iollo
Keyword(s):  
Water Distribution ◽  
Numerical Models ◽  
Uncertainty Propagation ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Monte Carlo Sampling ◽  
Collocation Methods ◽  
Water Age ◽  
True Value ◽  
Definition Of

Water distribution networks are critical infrastructures that should ensure the reliable supply of high quality potable water to its users. Numerical models of these networks are generally governed by many parameters for which the true value is unknown. This may be due to a lack of knowledge like for consumer demand or due to a lack of accessibility as for the pipe roughness. For network managers, the effect of these uncertainties on the network state is important information that supports them in the decision-making process. This effect is generally evaluated by propagating the uncertainties using the mathematical model. In the past, perturbation and stochastic collocation methods have been used for uncertainty propagation. However, these methods are limited either in the accuracy of the results or the complexity of the calculation. This paper uses an alternative spectral approach with the polynomial chaos expansion that has the potential to give comparable results to the Monte Carlo sampling through the definition of a stochastic model. This approach is applied to the model of a water distribution network in order to evaluate the influence of uncertain demands on the water age.

scholarly journals Uncertainty quantification of water age in water supply systems by use of spectral propagation

2019 ◽  
Vol 22 (1) ◽  
pp. 111-120 ◽  
Author(s):  
Mathias Braun ◽  
Olivier Piller ◽  
Jochen Deuerlein ◽  
Iraj Mortazavi ◽  
Angelo Iollo
Keyword(s):  
Water Distribution ◽  
Numerical Models ◽  
Uncertainty Propagation ◽  
Distribution Networks ◽  
Monte Carlo Sampling ◽  
Computational Effort ◽  
Collocation Methods ◽  
Water Supply Systems ◽  
Water Age ◽  
Precise Knowledge

Abstract Water distribution networks are critical infrastructures that should ensure the reliable supply of high quality potable water to its users. Numerical models of these networks are generally governed by many parameters for which the exact value is not known. This may be due to a lack of precise knowledge like for consumer demand or due to a lack of accessibility as for the pipe roughness. For network managers, the effect of these uncertainties on the network state is important information that supports them in the decision-making process. This effect is generally evaluated by propagating the uncertainties using the mathematical model. In the past, perturbation, fuzzy and stochastic collocation methods have been used for uncertainty propagation. However, these methods are limited either in the accuracy of the results or the computational effort of the necessary calculations. This paper uses an alternative spectral approach that uses the polynomial chaos expansion and has the potential to give results of comparable accuracy to the Monte Carlo sampling through the definition of a stochastic model. This approach is applied to the hydraulic model of two real networks in order to evaluate the influence of uncertain demands on the water age.

scholarly journals Pressure Regulation vs. Water Aging in Water Distribution Networks

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1323 ◽  
Author(s):  
Menelaos Patelis ◽  
Vasilis Kanakoudis ◽  
Anastasia Kravvari
Keyword(s):  
Water Distribution ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
High Water ◽  
Pressure Regulation ◽  
Water Age ◽  
Hydraulic Simulation ◽  
Annual Water ◽  
Winter Time ◽  
The Impact

In this paper, the effects of pressure regulation in a water distribution network (WDN) are being examined. Quality is hammered the most when pressure is reduced in a WDN and this occurs due to the increase in the age of water flowing inside the network pipes (water age is actually the total time the water remains inside the pipes before reaching the customer’s tap). Kos town WDN is used as the case study network. Kos town is the capital of the homonymous Greek island, among the most famous and popular of the Greek islands. The specific WDN is quite typical but very interesting, as it is extended along the seafront. The network’s hydraulic simulation model was developed through the WaterCad V8i software. As Kos experiences too high-water demand peaks and lows during summer and winter time, respectively, its WDN has already been thoroughly studied, in order to regulate the pressure and reduce its annual water loss rates. Nevertheless, these scenarios have never been examined regarding the impact on water quality. In the current study, the division of the WDN in District Metered Areas (DMAs) and the use of a Pressure Reducing Valve (PRV) in the entering node of each DMA are being evaluated in terms of water age. Additionally, a swift optimization process takes place to produce different DMAs’ borders, based on the criteria of minimum nodal water age, instead of optimal pressure. Different scenarios were tested on the calibrated and validated hydraulic model of Kos town WDN.

scholarly journals Optimizing the Formation of DMAs in a Water Distribution Network Applying Geometric Partitioning (GP) and Gaussian Mixture Models (GMMs)

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 601 ◽  
Author(s):  
Stavroula Chatzivasili ◽  
Katerina Papadimitriou ◽  
Vasilis Kanakoudis ◽  
Menelaos Patelis
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Gaussian Mixture ◽  
Optimal Placement ◽  
Water Age ◽  
Optimal Separation ◽  
Geometric Partitioning

In the last three decades, the need of achieving a reliable water distribution system has become more eminent for both the consumer’s satisfaction and the efficient management of water sources. The purpose of this paper is to provide an optimal separation of a water distribution network (WDN) into District Metered Areas (DMAs) in order to ensure that the delivered water is of proper age and pressure. At first, the water distribution network is divided into smaller areas via the method of Geometric Partitioning, which is based on Recursive Coordinate Bisection (RCB). Subsequently, Gaussian Mixture Modelling (GMM) solution is applied, obtaining an optimal placement of isolation valves and separation of the WDN into DMAs. The performance of the proposed system is evaluated on two different networks and is compared against the Genetic Algorithm (GA) tool, constituting a very promising approach, especially for sizeable water distribution networks due to the diminished running time and the noteworthy reduction of pressure and water age.

scholarly journals Identification of Critical Pipes Using a Criticality Index in Water Distribution Networks

2019 ◽  
Vol 9 (19) ◽  
pp. 4052 ◽  
Author(s):  
Malvin S. Marlim ◽  
Gimoon Jeong ◽  
Doosun Kang
Keyword(s):  
Water Distribution ◽  
Critical Infrastructure ◽  
Economic Value ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Simulation Approach ◽  
Water Age ◽  
Water Service ◽  
Critical Elements ◽  
Value Loss

A water distribution network (WDN) is a critical infrastructure that must be maintained, ensuring a proper water supply to widespread customers. A WDN consists of various components, such as pipes, valves, pumps, and tanks, and these elements interact with each other to provide adequate system performance. If the elements fail due to internal or external interruptions, this may adversely impact water service to different degrees depending on the failed elements. To determine an appropriate maintenance priority, the critical elements need to be identified and mapped in the network. To identify and prioritize the critical elements (here, we focus on the pipes only) in the WDN, an element-based simulation approach is proposed, in which all the composing pipes of the WDN are reviewed one at a time. The element-based criticality is measured using several criticality indexes that are newly proposed in this study. The proposed criticality indexes are used to quantify the impacts of element failure to water service degradation. Here, four criticality indexes are developed: supply shortage (SS), economic value loss (EVL), pressure decline (PD), and water age degradation (WAD). Each of these indexes measures different aspects of the consequences, specifically social, economic, hydraulic, and water quality, respectively. The separate values of the indexes from all pipes in a network are then combined into a singular criticality value for assessment. For demonstration, the proposed approach is applied to four real WDNs to identify and prioritize the critical pipes. The proposed element-based simulation approach can be used to identify the critical components and setup maintenance scheduling of WDNs for preparedness of failure events.

scholarly journals On the Calibration of the Mathematical Laws for the Water Loss Estimation in Water Distribution Network

10.29007/rk2f ◽  
2018 ◽  
Author(s):  
Mauro De Marchis ◽  
Barbara Milici
Keyword(s):  
Water Distribution ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Polyethylene Pipes ◽  
Experimental Campaign ◽  
Total Head ◽  
Definition Of ◽  
The University ◽  
The Relationship ◽  
Model Water

The definition of the relationship between the leak outflow, the total head at the leak and other relevant parameters such as the pipe stiffness, the leak dimension and shape has been object of extensive studies 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 (WDNs). To investigate the effectiveness of the formulations suggested by different authors, an experimental campaign was carried out at the Environ- mental Hydraulic Laboratory of the University of Enna (Italy) for leaks of different shape and size in polyethylene pipes.

scholarly journals Optimizing Water Age and Pressure in Drinking Water Distribution Networks

2020 ◽  
Vol 2 (1) ◽  
pp. 51
Author(s):  
Nikolaos Kourbasis ◽  
Menelaos Patelis ◽  
Stavroula Tsitsifli ◽  
Vasilis Kanakoudis
Keyword(s):  
Water Distribution ◽  
Water Pressure ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Water Distribution Networks ◽  
Operating Pressure ◽  
Water Age ◽  
Water Losses ◽  
Simulation And Optimization

Water distribution networks suffer from high levels of water losses due to leaks and breaks, mainly due to high operating pressure. One of the most well-known methods to reduce water losses is pressure management. However, when the operating pressure in a water distribution network reduces, the time the water stays within the network (called water age) increases. Increased water age means deteriorated water quality. In this paper, water pressure in relation to water age is addressed in a water distribution network in Greece. Using simulation and optimization tools, the optimum solution is found to reduce water age and operating pressure at the same time. In addition, District Metered Areas are formed and water age is optimized.

Security and redundancy in trunk main distribution networks

2003 ◽  
Vol 3 (1-2) ◽  
pp. 103-109
Author(s):  
A. Wallen ◽  
T. Woodward ◽  
R. Powell
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Distribution Networks ◽  
Security Level ◽  
Water Age ◽  
Network Modelling ◽  
System A ◽  
Hydraulic Network ◽  
Definition Of ◽  
The Cost

A methodology is being developed that may be incorporated in a hydraulic network modelling tool to analyse redundancy in the trunk main network of a water distribution system. A rigorous definition of the terms redundancy and security are given in this paper. Redundancy in the trunk main infrastructure is assessed in terms of supply security, which is the probability of water of adequate pressure, quality and appearance reaching the demand nodes. Supply security is increased by providing multiple supply routes to demand nodes so that there is minimal supply interruption in the case of failure of a network component. This paper presents a method that evaluates supply security under network conditions caused by trunk main failures. The supply security level ensured by multiple pipe routes is compared with the costs of maintaining additional routes. Three indices are used as measures of the cost of additional infrastructure: network condition, water age and link failure probability. The fitness of a trunk main system is evaluated in terms of supply security and infrastructure costs. The system may then be modified using a genetic algorithm to create a population of reduced networks, from which infrastructure which may be redundant has been removed. The fitness of each reduced network is assessed, compared with the fittest network, and progressive generations are developed using the algorithm, until an improved network is selected.

A study on appropriate investment of pipeline rehabilitation for water distribution network

2005 ◽  
Vol 5 (2) ◽  
pp. 31-38
Author(s):  
A. Asakura ◽  
A. Koizumi ◽  
O. Odanagi ◽  
H. Watanabe ◽  
T. Inakazu
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Water Supply ◽  
Water Distribution ◽  
Ad Hoc ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Optimal Basis ◽  
Model Case

In Japan most of the water distribution networks were constructed during the 1960s to 1970s. Since these pipelines were used for a long period, pipeline rehabilitation is necessary to maintain water supply. Although investment for pipeline rehabilitation has to be planned in terms of cost-effectiveness, no standard method has been established because pipelines were replaced on emergency and ad hoc basis in the past. In this paper, a method to determine the maintenance of the water supply on an optimal basis with a fixed budget for a water distribution network is proposed. Firstly, a method to quantify the benefits of pipeline rehabilitation is examined. Secondly, two models using Integer Programming and Monte Carlo simulation to maximize the benefits of pipeline rehabilitation with limited budget were considered, and they are applied to a model case and a case study. Based on these studies, it is concluded that the Monte Carlo simulation model to calculate the appropriate investment for the pipeline rehabilitation planning is both convenient and practical.

scholarly journals Assessing the Impact of DMAs and the Use of Boosters on Chlorination in a Water Distribution Network in Greece

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2141
Author(s):  
Stavroula Tsitsifli ◽  
Vasilis Kanakoudis
Keyword(s):  
Water Distribution ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Assessment Process ◽  
Water Volume ◽  
Pressure Management ◽  
Water Age ◽  
Chlorination Process ◽  
Management Measures ◽  
The Impact

Disinfection is one of the most important water treatment processes as it inactivates pathogens providing safe drinking water to the consumers. A fresh-water distribution network is a complex system where constant monitoring of several parameters and related managerial decisions take place in order for the network to operate in the most efficient way. However, there are cases where some of the decisions made to improve the network’s performance level, such as reduction of water losses, may have negative impacts on other significant operational processes such as the disinfection. In particular, the division of a water distribution network into district metered areas (DMAs) and the application of various pressure management measures may impact the effectiveness of the water chlorination process. Two operational measures are assessed in this paper: (a) the use of inline chlorination boosters to achieve more efficient chlorination; and (b) how the DMAs formation impacts the chlorination process. To achieve this, the water distribution network of a Greek town is chosen as a case study where several scenarios are being thoroughly analyzed. The assessment process utilizes the network’s hydraulic simulation model, which is set up in Watergems V8i software, forming the baseline to develop the network’s water quality model. The results proved that inline chlorination boosters ensure a more efficient disinfection, especially at the most remote parts/nodes of the network, compared to conventional chlorination processes (e.g., at the water tanks), achieving 100% safe water volume and consuming almost 50% less chlorine mass. DMAs’ formation results in increased water age values up to 8.27%, especially at the remote parts/nodes of the network and require more time to achieve the necessary minimum effective chlorine concentration of 0.2 mg/L. However, DMAs formation and pressure management measures do not threaten the chlorination’s efficiency. It is important to include water age and residual chlorine as criteria when optimizing water pressure and the division of DMAs.

Study on the impacts of peaking factors on a water distribution system in Germany

2010 ◽  
Vol 10 (2) ◽  
pp. 165-172 ◽  
Author(s):  
K. Diao ◽  
M. Barjenbruch ◽  
U. Bracklow
Keyword(s):  
Energy Consumption ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Water Distribution Network ◽  
Design Stage ◽  
Water Age ◽  
Specific System ◽  
Average Water

This paper aims to explore the impacts of peaking factors on a water distribution system designed for a small city in Germany through model-based analysis. As a case study, the water distribution network was modelled by EPANET and then two specific studies were carried out. The first study tested corresponding system-wide influences on water age and energy consumption if the peaking factors used at design stage are inconsistent with ones in real situation. The second study inspected the possible relationship between the choice of peaking factors and budgets by comparing several different pipe configurations of the distribution system, obtained according to variety of peaking factors. Given the analysis results, the first study reveals that average water age will increase if peaking factors estimated at design stage are larger than real values in that specific system, and vice versa. In contrast, energy consumption will increase if peaking factors defined for system design are smaller than ones in real case, and vice versa. According to the second study, it might be possible to amplify peaking factors for design dramatically by a slight increase in the investment on this system. However, further study on budget estimation with more factors and detailed information considered should be carried out.

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