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

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.

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1521
Author(s):  
Kegong Diao

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.


2010 ◽  
Vol 10 (4) ◽  
pp. 600-609 ◽  
Author(s):  
R. Sitzenfrei ◽  
S. Fach ◽  
M. Kleidorfer ◽  
C. Urich ◽  
W. Rauch

In environmental engineering, identification of problems and their solutions as well as the identification of the relevant processes involved is often done by means of case study analyses. By researching the operation of urban drainage and water distribution systems, this methodology is suited to evaluate new technologies, strategies or measures with regard to their impact on the overall processes. However, data availability is often limited and data collection and the development of new models are both costly and time consuming. Hence, new technologies, strategies or measures can only be tested on a limited number of case studies. In several environmental disciplines a few virtual case studies have been manually developed to provide data for research tasks and these are repeatedly used in different research projects. Efforts have also been invested in tackling limited data availability with the algorithmic generation of virtual case studies having constant or varying boundary conditions. The data provided by such tools is nevertheless only available for a certain instance in time. With DynaVIBe (Dynamic Virtual Infrastructure Benchmarking), numerous virtual case studies are algorithmically generated with a temporal development of the urban structure (population and land use model) and infrastructure. This provides a methodology that allows for the analysis of future scenarios on a spatio-temporal city scale. By linking a population model with DynaVIBe's infrastructure models, socio-economics impacts on infrastructure and system coherences can be investigated. The problematic of limited case study data is solved by the algorithmic generation of an unlimited number of virtual case studies, which are dynamic over time. Additionally, this methodology can also be applied on real world data for probabilistic future scenario analysis.


2007 ◽  
Vol 56 (9) ◽  
pp. 29-36 ◽  
Author(s):  
M. Möderl ◽  
T. Fetz ◽  
W. Rauch

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.


2010 ◽  
Vol 12 (4) ◽  
pp. 424-445 ◽  
Author(s):  
Stefano Alvisi ◽  
Marco Franchini

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.


Water SA ◽  
2020 ◽  
Vol 46 (3 July) ◽  
Author(s):  
Tiku T Tanyimboh ◽  
Alemtsehay G Seyoum

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.


WRPMD'99 ◽  
1999 ◽  
Author(s):  
P. Costa ◽  
A. Esposito ◽  
C. Gualtieri ◽  
D. Pianese ◽  
G. Pulci Doria ◽  
...  

Author(s):  
Mietek A. Brdys ◽  
Kazimierz Duzinkiewicz ◽  
Michal Grochowski ◽  
Tomasz Rutkowski

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