scholarly journals Multiscale Resilience in Water Distribution and Drainage Systems

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1521
Author(s):  
Kegong Diao
Keyword(s):  
Case Studies ◽  
Real World ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Water Systems ◽  
Urban Drainage ◽  
Main Function ◽  
Drainage Systems ◽  
Single Scale

Multiscale resilience, i.e., coordinating different scales within a system to jointly cope and mitigate risks on any single scale, is identified as the feature of a complex resilient system. However, in water distribution systems (WDSs) and urban drainage systems (UDSs), the inherent resilience is usually not multiscale resilience. By referring to the larger scale to larger pipes serving both local users and some other users at smaller scales, it can be found that smaller scales are not responsible for providing resilience to cope with failures in larger scales. These are because the main function of traditional water systems is to deliver water from upstream to downstream. This study demonstrates that improving multiscale resilience in WDSs and UDSs needs to allow water to travel reversely in the system via providing extra capacities and/or connections at smaller scales. This hypothesis is verified via case studies on a real world WDS and UDS.

Graph-based approach for generating virtual water distribution systems in the software VIBe

2010 ◽  
Vol 10 (6) ◽  
pp. 923-932 ◽  
Author(s):  
R. Sitzenfrei ◽  
M. Möderl ◽  
W. Rauch
Keyword(s):  
Case Studies ◽  
Real World ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Virtual Water ◽  
Systematic Investigation ◽  
Quality Performance ◽  
Virtual Infrastructure ◽  
Spatially Distributed

Application of virtual case studies (VCS) is a well established technique in environmental engineering to test measures, approaches, models or software. However, preparation of VCS for an infrastructure network is a tedious task. In literature, approaches can be found which generate very simplified VCS, which are only partly comparable with real world case studies. VCS which are more comparable with real world case studies can be generated with the software VIBe (Virtual Infrastructure Benchmarking). With VIBe, a methodology for algorithmic generation of VCS with varying spatially distributed boundary conditions was presented. Therein the investigated infrastructure is constructed accordingly to the state-of-the-art design rules meeting the requirements of the generated virtual urban environment. In this paper the module for the generation of water distribution systems (WDS) is presented. The generated WDS are set in context with data from real world WDS and systematically investigated. A set of 75,000 virtual WDS with varying properties is characterized and stochastically analysed in order to identify system coherences e.g. impact of mesh degree on hydraulic, water quality performance and costs. An example involving the systematic investigation of a simple pipe sizing algorithm with the set of 75,000 WDS is shown.

scholarly journals MUWS (Microbiology in Urban Water Systems) – an interdisciplinary approach to study microbial communities in urban water systems

2010 ◽  
Vol 3 (2) ◽  
pp. 91-99 ◽  
Author(s):  
P. Deines ◽  
R. Sekar ◽  
H. S. Jensen ◽  
S. Tait ◽  
J. B. Boxall ◽  
...  
Keyword(s):  
Microbial Ecology ◽  
Distribution Systems ◽  
Water Distribution ◽  
Potable Water ◽  
Water Distribution Systems ◽  
Water Systems ◽  
Urban Water ◽  
Infrastructure Systems ◽  
Urban Water Systems ◽  
Sewer Networks

Abstract. Microbiology in Urban Water Systems (MUWS) is an integrated project, which aims to characterize the microorganisms found in both potable water distribution systems and sewer networks. These large infrastructure systems have a major impact on our quality of life, and despite the importance of these systems as major components of the water cycle, little is known about their microbial ecology. Potable water distribution systems and sewer networks are both large, highly interconnected, dynamic, subject to time and varying inputs and demands, and difficult to control. Their performance also faces increasing loading due to increasing urbanization and longer-term environmental changes. Therefore, understanding the link between microbial ecology and any potential impacts on short or long-term engineering performance within urban water infrastructure systems is important. By combining the strengths and research expertise of civil-, biochemical engineers and molecular microbial ecologists, we ultimately aim to link microbial community abundance, diversity and function to physical and engineering variables so that novel insights into the performance and management of both water distribution systems and sewer networks can be explored. By presenting the details and principals behind the molecular microbiological techniques that we use, this paper demonstrates the potential of an integrated approach to better understand how urban water system function, and so meet future challenges.

Fungi from Potable Water: Interaction with Chlorine and Engineering Effects

1988 ◽  
Vol 20 (11-12) ◽  
pp. 153-159 ◽  
Author(s):  
William D. Rosenzweig ◽  
Wesley O. Pipes
Keyword(s):  
Water Samples ◽  
Distribution Systems ◽  
Water Distribution ◽  
Potable Water ◽  
Fungal Spores ◽  
Water Distribution Systems ◽  
Water Systems ◽  
Storage Tanks ◽  
Water Interaction ◽  
Low Concentrations

In recent years various types of imperfect fungi have been isolated from water systems. Fungal spores and mycelia can be inactivated by low concentrations of chlorine in the laboratory but survive in some habitats in water distribution systems. This report describes a field study which provides evidence that some types of fungi are able to grow in water distribution systems. Replicate samples from private residences were used to demonstrate that fungal densities are sometimes much greater than the levels which could be explained by adventitious spores. The microbiological content of water samples from fire hydrants was often significantly different from that of water samples from nearby private residences. The treated water input to distribution systems was found to be significantly lower in fungus content than water from private residences. Elevated storage tanks open to the atmosphere appear to be significant sources of fungal input to some systems.

Stochastic approach for performance evaluation regarding water distribution systems

2007 ◽  
Vol 56 (9) ◽  
pp. 29-36 ◽  
Author(s):  
M. Möderl ◽  
T. Fetz ◽  
W. Rauch
Keyword(s):  
Performance Evaluation ◽  
Case Studies ◽  
Distribution Systems ◽  
Water Distribution ◽  
Performance Indicator ◽  
Water Distribution Systems ◽  
Stochastic Approach ◽  
Cumulative Distribution ◽  
Design System ◽  
The Impact

A traditional procedure for performance evaluation of systems is to test approaches on one or more case studies. However, it is well known that the investigation of real case studies is a tedious task. Moreover, due to the limited amount of case studies available it is not certain that all aspects of a problem can be covered in such procedure. With increasing computer power an alternative methodology has emerged, that is the investigation of a multitude of virtual case studies by means of a stochastic consideration of the overall performance. Within the frame of this approach we develop here a modular design system (MDS) for water distribution systems (WDSs). With the algorithmic application of such a MDS it is possible to create a variety of different WDSs. As an example of stochastic performance evaluation the impact of pipe breakages on WDSs is estimated applying a pressure driven performance indicator. This performance indicator is evaluated stochastically. Likewise the performance evaluation of a variety of WDSs is also performed stochastically. Cumulative distribution function, histogram and other statistical properties of 2,280×1,000 performance results of the different WDSs are calculated to highlight the applicability of the introduced stochastic approach.

Memphis Light, Gas and Water Division Experience With Aging of Electric, Gas, and Water Systems

1993 ◽  
Vol 46 (5) ◽  
pp. 183-186
Author(s):  
Charles Pickel
Keyword(s):  
United States ◽  
Customer Satisfaction ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
The United States ◽  
Water Systems ◽  
Recent Survey ◽  
Effective Manner ◽  
Long Life

Electric, gas and water distribution systems can have an extremely long life when properly designed, installed and maintained. MLGW is proof positive that aging distribution systems can be managed in an effective manner. Customer satisfaction is a high priority with Division management. According to a recent survey, Memphians enjoy the lowest average monthly utility bills among the 25 largest cities in the United States.

scholarly journals MUWS (Microbiology in Urban Water Systems) – an interdisciplinary approach to study microbial communities in urban water systems

2010 ◽  
Vol 3 (1) ◽  
pp. 43-64
Author(s):  
P. Deines ◽  
R. Sekar ◽  
H. S. Jensen ◽  
S. Tait ◽  
J. B. Boxall ◽  
...  
Keyword(s):  
Microbial Ecology ◽  
Distribution Systems ◽  
Water Distribution ◽  
Potable Water ◽  
Water Distribution Systems ◽  
Water Systems ◽  
Urban Water ◽  
Microbiological Methods ◽  
Urban Water Systems ◽  
Sewer Networks

Abstract. Microbiology in Urban Water Systems (MUWS) is an integrated project, which aims to characterize the microorganisms found in both potable water distribution systems and sewer networks. These large infrastructure systems have a major impact on our quality of life, and despite the importance of these systems as major components of the water cycle, little is known about their microbial ecology. Potable water distribution systems are large, highly interconnected and dynamic, and difficult to control. Sewer systems are also large and subject to time varying inputs and demands. Their performance also faces increasing loading due to increasing urbanization and longer-term environmental changes. Therefore, understanding the link between microbial ecology and any potential impacts on short or long-term engineering performance is important. By combining the strengths and research expertise of civil-, biochemical engineers and molecular microbial ecologists, we aim to link the abundance and diversity of microorganisms to physical and engineering variables so that novel insights into the ecology of microorganisms within both water distribution systems and sewer networks can be explored. By presenting the details of this multidisciplinary approach, and the principals behind the molecular microbiological methods and techniques that we use, this paper will demonstrate the potential of an integrated approach to better understand urban water system function and so meet future challenges.

A stochastic approach for automatic generation of urban drainage systems

2009 ◽  
Vol 59 (6) ◽  
pp. 1137-1143 ◽  
Author(s):  
M. Möderl ◽  
D. Butler ◽  
W. Rauch
Keyword(s):  
Case Studies ◽  
Real World ◽  
Drainage System ◽  
Stochastic Approach ◽  
Automatic Generation ◽  
Urban Drainage ◽  
Sewer System ◽  
Urban Drainage System ◽  
Drainage Systems ◽  
Urban Drainage Systems

Typically, performance evaluation of new developed methodologies is based on one or more case studies. The investigation of multiple real world case studies is tedious and time consuming. Moreover extrapolating conclusions from individual investigations to a general basis is arguable and sometimes even wrong. In this article a stochastic approach is presented to evaluate new developed methodologies on a broader basis. For the approach the Matlab-tool “Case Study Generator” is developed which generates a variety of different virtual urban drainage systems automatically using boundary conditions e.g. length of urban drainage system, slope of catchment surface, etc. as input. The layout of the sewer system is based on an adapted Galton-Watson branching process. The sub catchments are allocated considering a digital terrain model. Sewer system components are designed according to standard values. In total, 10,000 different virtual case studies of urban drainage system are generated and simulated. Consequently, simulation results are evaluated using a performance indicator for surface flooding. Comparison between results of the virtual and two real world case studies indicates the promise of the method. The novelty of the approach is that it is possible to get more general conclusions in contrast to traditional evaluations with few case studies.

scholarly journals Pipe roughness calibration in water distribution systems using grey numbers

2010 ◽  
Vol 12 (4) ◽  
pp. 424-445 ◽  
Author(s):  
Stefano Alvisi ◽  
Marco Franchini
Keyword(s):  
Case Studies ◽  
Measurement Errors ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Taylor Series Expansion ◽  
Calibration Procedure ◽  
General Nature ◽  
Function Evaluation ◽  
Pipe Roughness

This paper presents a procedure based on the use of grey numbers for the calibration (with uncertainty) of pipe roughness in water distribution systems. The pipe roughness uncertainty is represented through the grey number amplitude (or interval). The procedure is of a wholly general nature and can be applied for the calibration (with uncertainty) of other parameters or quantities, such as nodal demands. In this paper, for the purpose of roughness calibration, a certain number of nodal head measurements made under different demand conditions is assumed to be available at different locations (nodes); all other topological and geometric characteristics of the system are considered to be known exactly. The general approach to pipe roughness calibration (taking account of uncertainty) focuses on identifying the grey roughness values which produce grey head values at the measuring nodes such as to encompass the observed values grouped on the basis of the different demand scenarios and, at the same time, have as small an ‘amplitude’ as possible. The proposed procedure was applied to two synthetic case studies and to one real network. The tests on the synthetic case studies show that the proposed procedure is able to correctly solve the inverse problem, i.e. it can identify the known grey roughness numbers even when they overlap; the same applies when the known grey roughness numbers collapse into known white roughness numbers. The test on the real case offers the possibility of highlighting the potentials of the procedure when applied within a context where measurement errors and other uncertainties are present. The procedure entails computing times that may become lengthy. However, it is possible to reduce these computing times considerably by replacing the hydraulic simulator—to which a number of calls must be made during the calibration procedure (for objective function evaluation)—with an approximation based on a first-order Taylor series expansion. This approach introduces acceptable approximations within the context of the problem considered.

scholarly journals Design optimization of water distribution networks: real-world case study with penalty-free multi-objective genetic algorithm using pressure-driven simulation

Water SA ◽  
2020 ◽  
Vol 46 (3 July) ◽  
Author(s):  
Tiku T Tanyimboh ◽  
Alemtsehay G Seyoum
Keyword(s):  
Genetic Algorithm ◽  
Design Optimization ◽  
Real World ◽  
Distribution Systems ◽  
Water Distribution ◽  
Distribution Network ◽  
Water Distribution Systems ◽  
Active Constraint ◽  
Multi Objective ◽  
Multi Objective Genetic Algorithm

Water distribution systems are an integral part of the economic infrastructure of modern-day societies. However, previous research on the design optimization of water distribution systems generally involved few decision variables and consequently small solution spaces; piecemeal-solution methods based on pre-processing and search space reduction; and/or combinations of techniques working in concert. The present investigation was motivated by the desire to address the above-mentioned issues including those associated with the lack of high-performance computing (HPC) expertise and limited access in developing countries. More specifically, the article’s aims are, firstly, to solve a practical water distribution network design optimization problem and, secondly, to develop and demonstrate a generic multi-objective genetic algorithm capable of achieving optimal and near-optimal solutions on complex real-world design optimization problems reliably and quickly. A multi-objective genetic algorithm was developed that applies sustained and extensive exploration of the active constraint boundaries. The computational efficiency was demonstrated by the small fraction of 10-245 function evaluations relative to the size of the solution space. Highly competitive solutions were achieved consistently, including a new best solution. The water utility’s detailed distribution network model in EPANET 2 was used for the hydraulic simulations. Therefore, with some additional improvements, the optimization algorithm developed could assist practitioners in day-to-day planning and design.

Occurrence of legionellae in hot water distribution systems of Finnish apartment buildings

1994 ◽  
Vol 40 (12) ◽  
pp. 993-999 ◽  
Author(s):  
Outi M. Zacheus ◽  
Pertti J. Martikainen
Keyword(s):  
Surface Water ◽  
Ground Water ◽  
Water Temperature ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Water Systems ◽  
Hot Water ◽  
Apartment Buildings ◽  
Water Plants

The occurrence of legionellae in the hot water distribution systems of 67 buildings located in different parts of Finland was studied. Most of the buildings were apartment buildings. They had different hot water temperatures, and some received their cold potable water from surface water plants and some from ground water plants. Hot water samples were taken from taps, showers, and water mains just before and after the heat exchanger. Legionella pneumophila was isolated from 30% of the distribution systems. In the legionella-positive samples the legionella concentration varied from < 50 to 3.2 × 105 colony-forming units (cfu)/L (mean 2.7 × 103 cfu/L). The highest concentration of legionellae was found in the shower water. Legionellae appeared more often and with higher concentrations in hot water systems using cold water processed in surface water plants than in hot water systems associated with ground water plants. A high organic matter content in surface waters might favor the occurrence of legionellae and also the growth of other heterotrophic microbes. Mean water temperature just after heating was slightly higher in the legionella-negative systems than in the legionella-positive systems (53.5 vs. 51.5 °C).Key words: Legionella, organic carbon, hot water distribution system, water temperature.

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