scholarly journals Dynamical stability of water distribution networks

Author(s):  
Naoki Masuda ◽  
Fanlin Meng

Water distribution networks are hydraulic infrastructures that aim to meet water demands at their various nodes. Water flows through pipes in the network create nonlinear dynamics on networks. A desirable feature of water distribution networks is high resistance to failures and other shocks to the system. Such threats would at least transiently change the flow rate in various pipes, potentially undermining the functionality of the whole water distribution system. Here we carry out a linear stability analysis for a nonlinear dynamical system representing the flow rate through pipes that are interconnected through an arbitrary pipe network with reservoirs and consumer nodes. We show that the steady state is always locally stable and develop a method to calculate the eigenvalue that corresponds to the mode that decays the most slowly towards the equilibrium, which we use as an index for resilience of the system. We show that the proposed index is positively correlated with the recovery rate of the pipe network, which was derived from a realistic and industrially popular simulator. The present analytical framework is expected to be useful for deploying tools from nonlinear dynamics and network analysis in the design, resilience management and scenario testing of water distribution networks.

Water ◽  
2016 ◽  
Vol 8 (12) ◽  
pp. 575 ◽  
Author(s):  
Christian León-Celi ◽  
Pedro Iglesias-Rey ◽  
F. Martínez-Solano ◽  
Daniel Mora-Melia

2019 ◽  
Vol 63 (4) ◽  
pp. 295-300 ◽  
Author(s):  
Tamás Huzsvár ◽  
Richárd Wéber ◽  
Csaba János Hős

One of the basic infrastructures of every settlement is the water distribution system, which provides clean and potable water for both private houses, industrial consumers and institution establishments. The operational robustness and vulnerabilities of these networks is an essential issue, both for the quality of life and for the preservation of the environment. Even with frequent and careful maintenance, unintentional pipe bursts might occur, and during the reparation time, the damaged section must be isolated hydraulically from the main body of the water distribution network. Due to the size and complexity of these networks, it might not be trivial how to isolate the burst section, especially if one wishes to minimize the impact on the overall system. This paper presents an algorithmic method that is capable of creating isolation plans for real-life networks in a computationally efficient way, based on the graph properties of the network. Besides this segmentation plan, the topological behavior of the structural graph properties was analyzed with the help of the complex network theory to create a method for the quantitative topology based categorization of the water distribution networks.


2006 ◽  
Vol 53 (4-5) ◽  
pp. 503-511 ◽  
Author(s):  
D. Misiunas ◽  
J. Vítkovský ◽  
G. Olsson ◽  
M. Lambert ◽  
A. Simpson

An algorithm for the burst detection and location in water distribution networks based on the continuous monitoring of the flow rate at the entry point of the network and the pressure at a number of points within the network is presented. The approach is designed for medium to large bursts with opening times in the order of a few minutes and is suitable for networks of relatively small size, such as district metered areas (DMAs). The burst-induced increase in the inlet flow rate is detected using the modified cumulative sum (CUSUM) change detection test. Based on parameters obtained from the CUSUM test, the burst is simulated at a number of burst candidate locations. The calculated changes in pressure at the pressure monitoring points are then compared to the measured values and the location resulting in the best fit is selected as the burst location. The EPANET steady-state hydraulic solver is utilised to simulate the flows and pressures in the network. A sensitivity-based sampling design procedure is introduced to find the optimal positions for pressure monitoring points. The proposed algorithm is tested on a case study example network and shows potential for burst detection and location in real water distribution systems.


2021 ◽  
Author(s):  
Ran Yan ◽  
Yu Li ◽  
Jinhui Jeanne Huang

<p>During January 2016 and December 2020, eastern and southern China including Shanghai experienced a rapid drop in temperatures along with snow. This cold wave which also had a severe impact on water distribution networks. Leakage of pipe network causes serious economic loss and waste of water resources. Nonetheless, cold wave is not the only factor affecting leakage from a pipe network. There are also other factors including the burial depth of pipes, the materials of pipes, the diameters of pipes, break history and so on. In this work, we use machine learning method and Bayesian distribution regression to explore the relationship between pipe leaks and impact factors. Based on results, risk maps of water distribution networks are generated. This research indicated that which risk factors is important for leakage detection and water loss management of urban water supply network, which can be promising for wide practical applications due to rapid expansion of data.</p>


Water distribution through pipe networks is considered a significant in human civilization. The percentage of population served by these networks is increasing continuously and the reliability studies of these networks are given more importance. In the recent years, resilience a form of reliability of the system, of water distribution networks, gained significant focus. Some of the popular resilience indicators developed by researchers are critically analyzed in this work. The limitations of the resilience indicators presented in this paper indicate the necessity to improve the indicators and develop new robust indicators


2013 ◽  
Vol 6 (1) ◽  
pp. 25-31 ◽  
Author(s):  
L. Mezule ◽  
S. Larsson ◽  
T. Juhna

Abstract. Sporadic detection of live (viable) Escherichia coli in drinking water and biofilm with molecular methods but not with standard plate counts has raised concerns about the reliability of this indicator in the surveillance of drinking water safety. The aim of this study was to determine spatial distribution of different viability forms of E. coli in a drinking water distribution system which complies with European Drinking Water Directive (98/83/EC). For two years coupons (two week old) and pre-concentrated (100 times with ultrafilters) water samples were collected after treatment plants and from four sites in the distribution network at several distances. The samples were analyzed for total, viable (able to divide as DVC-FISH positive) and cultivable E. coli. The results showed that low numbers of E. coli enters the distribution sytem from the treatment plants and tend to accumulate in the biofilm of water distribution system. Almost all of the samples contained metabolically active E. coli in the range of 1 to 50 cells per litre or cm2 which represented approximately 53% of all E. coli detected. The amount of viable E. coli significantly increased into the network irrespective of the season. The study has shown that DVC-FISH method in combination with water pre-concentration and biofilm sampling allows to better understand the behaviour of E. coli in water distribution networks, thus, it provides new evidences for water safety control.


2020 ◽  
Vol 10 (9) ◽  
pp. 3029 ◽  
Author(s):  
Attilio Fiorini Morosini ◽  
Sina Shaffiee Haghshenas ◽  
Sami Shaffiee Haghshenas ◽  
Zong Woo Geem

Investigation of Water Distribution Networks (WDNs) is considered a challenging task due to the unpredicted and uncertain conditions in water engineering. When in a WDN, a pipe failure occurs, and shut-off valves to isolate the broken pipe to allow repairing works are activated. In these new conditions, the hydraulic parameters in the network are modified because the topology of the entire system changes. If the head becomes inadequate, the Pressure Driven Analysis (PDA) is the correct approach to evaluate the performance of water networks. Hence, in the present study, the water distribution system was evaluated in pressure-driven conditions for 100 different scenarios and then using a type of neural network called Group Method of Data Handling (GMDH) as a stochastic technique. For this purpose, several most notable parameters including the base demand, pressure, and alpha (the percentage of effective supplied flow) were calculated using simulations based on a PDA approach and applied to the water distribution network of Praia a Mare in Southern Italy. In the second stage, the output parameters were used in a developed binary classification model. Finally, the obtained results showed that the GMDH algorithm can be applied as a powerful tool for modeling water distribution networks.


2020 ◽  
Vol 2 (1) ◽  
pp. 48
Author(s):  
João Muranho ◽  
Ana Ferreira ◽  
Joaquim Sousa ◽  
Abel Gomes ◽  
Alfeu Sá Marques

EPANET uses a demand-driven approach to compute pressures and flows in the water distribution system. The demand-driven approach (DDA) assumes that the required demand is always fully satisfied no matter the existing pressure. In scenarios of pressure-deficient conditions the DDA results are not accurate, and a pressure-driven approach (PDA) is needed. Frequently, the PDA is accomplished by using equations that compute the available demand/leakage as a function of the current pressure. However, embedding such equations into the solver introduces convergence problems. This paper details the actions taken in WaterNetGen—an EPANET extension—to bring numerical stability to the pressure-driven solver, namely, by smoothing the pressure–demand/leakage relationship and the pump curve.


2019 ◽  
Vol 20 (1) ◽  
pp. 13-27 ◽  
Author(s):  
Prerna Pandey ◽  
Shilpa Dongre ◽  
Rajesh Gupta

Abstract The performance of a water distribution system of providing a required flow rate at all the nodes with required pressure heads throughout its design life is affected by uncertainties associated with different parameters such as future water demands, pipe roughness coefficient values, required pressure heads at nodes, etc. The objective of this paper is to present a comprehensive review on the nature of uncertainties (random or fuzzy), various models and methods used for their quantification, and different ways of handling them in the design of water distribution networks. While probabilistic based approaches are used for handling uncertainty of random type, the possibilistic based approach considers uncertainty of fuzzy nature. Some key issues and serious limitations of the existing approaches for modeling uncertain parameters related to water distribution networks are identified. The uncertainty in water demands is due to both their random nature and lack of information about their values. Therefore, a combination of both types of approaches, called the fuzzy random approach, is found to be more effective. The fuzzy random approach can provide optimal design solutions that are not only cost-effective but also has higher reliability to cope with severe future uncertainties.


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