Assessing mechanical vulnerability in water distribution networks under multiple failures

Berardi, Luigi; Ugarelli, Rita Maria; Røstum, Jon; Giustolisi, Orazio

doi:10.1002/2013wr014770

Cited by 47 publications

(28 citation statements)

References 32 publications

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“…A common constraint of the above approaches is that the combination of possible failure scenarios grows exponentially as the network becomes bigger (Berardi et al 2014) together with possible inconsistencies and uncertainties associated with hydraulic simulations (Gupta and Bhave 1994). Trifunović (2012) explores hydraulic properties of the network based on the statistical analysis of common parameters under normal operation and proposed them as indices to assess the resilience of a water network.…”

Section: Introductionmentioning

confidence: 99%

“…Beyond the implicit non-linearity, the number of parameters involved in the hydraulic equations and their large number of possible combinations introduce high complexity to the WDN calibration problem (an NP-Hard problem, which cannot be solved in polynomial time Takahashi et al (2010).) For large WDNs, these have an expensive computational cost since, even for moderate size networks, the number of possible failure scenarios grows exponentially and are approached using either some linearising assumptions or the use of heuristics for failure simulations (Berardi et al 2014).…”

Section: Introductionmentioning

confidence: 99%

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A Graph-Theoretic Framework for Assessing the Resilience of Sectorised Water Distribution Networks

Herrera

Abraham

Stoianov

2016

Water Resour Manage

150

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Water utilities face a challenge in maintaining a good quality of service under a wide range of operational management and failure conditions. Tools for assessing the resilience of water distribution networks are therefore essential for both operational and maintenance optimization. In this paper, a novel graph-theoretic approach for the assessment of resilience for large scale water distribution networks is presented. This is of great importance for the management of large scale water distribution systems, most models containing up to hundreds of thousands of pipes and nodes. The proposed framework is mainly based on quantifying the redundancy and capacity of all possible routes from demand nodes to their supply sources. This approach works well with large network sizes since it does not rely on precise hydraulic simulations, which require complex calibration processes and computation, while remaining meaningful from a physical and a topological point of view. The proposal is also tailored for the analysis of sectorised networks through a novel multiscale method for analysing connectivity, which is successfully tested in operational utility network models made of more than 100,000 nodes and 110,000 pipes.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Graph-Theoretic Framework for Assessing the Resilience of Sectorised Water Distribution Networks

Herrera

Abraham

Stoianov

2016

Water Resour Manage

150

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“…The reliability of a water supply system depends on its distributive efficiency [5]. A water distribution is system deemed reliable if it can withstand a predicted level of failure including against pressure surges [6] [7] [8]. In water works' landscape, the three determinants of system reliability are; quantity of water delivered at the right pressure and time, its quality and its affordability to all consumers equitably [9] [10].…”

Section: Water Supply Reliabilitymentioning

confidence: 99%

The Implication of Unreliable Urban Water Supply Service: The Case of Vendor Water Cost in Langata Sub County, Nairobi City, Kenya

Ochungo¹,

Ouma²,

Obiero³

et al. 2019

JWARP

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Studies on urban water supply service improvements continue to draw interest across the world. The pressure on freshwater resources is increasing in every region in the face of an increasing demand and climate change dynamics. Langata sub County in Nairobi city, Kenya faces drought induced water shortage and households rely on water vending and bottled water purchases to augment the inadequate municipal water supplies. Little to our knowledge has been done to assess the cost implication of such a practice here. So the study used household survey method to collect monthly households' water bills comprising; utility company, water tanker delivery and bottled water purchase from a randomly sampled 382 households spread within the five wards; Karen, South C, Mugumoini, Nairobi West and Nyayo Highrise. The gated communities identified are 57. Simple stochastic analysis of the data was done after data cleaning using MS Excel. It was found that the municipal water serves up to 91.15% of the total average household monthly water demand with a cost share of 27.91%. Water tanker delivery meets 8.61% of the household water demand with a cost share of 50.74%. The bottled water purchases serve 0.24% of a typical household water demand with a total cost share of 21.35%. The water supply deficit which is a mere 8.85% met by tanker deliveries and bottled water purchases has a total average cost share of 72.09%. The computed cost burden is 258%. This means that the households pay more than two and a half times extra above the utility bill per month. The study recommends a new water policy that will incorporate the role of water vendors operated on a cooperative model by the gated communities using standard guidelines. How to cite this paper: Ochungo, E.A., Journal of Water Resource and Protection vulnerability of public water supply systems to impacts of climate variability [26] [27] [28].Accordingly, households nowadays do supplement with vended water transported by one or a number of these methods: head-ported or hand-held water containers [29], walking tractors, bicycles, hand-carts/donkey carts [30] [31], motorbikes and owner-managed water access systems for a home or a community [32]. One other popular coping strategy is buying from neighbors; a practice found in Accra city, Ghana according to [33]. Such daily distressful struggles for water access service makes urban dualism concept real as the beneficiaries are known to be living in urban settings with on-site water utility infrastructure [34] [35]. Further, the selection of a choice of water source with a suitable quality is not easy [36]. Despite the prevailing choice quandary, water vendors serve about 10% -69% of households in developing nations' cities [37]. On the other hand, selling of water to customers is a very important economic activity to the vendors [38]. That is why they always choose to ignore repugnant waterscape labels like 'mafias' as in Bangalore city, India [39].

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“…The vulnerability assessment of a network [ Latora and Marchioni , ; Berardi et al ., ] can be simulated by removing nodes, i.e., the connected links, at random or by targeting those corresponding to an intentional attack; node removal changes the preferential paths between nodes, increasing the shortest paths. The behavior of Pareto or Poisson networks to nodal removal is different.…”

Section: Degree Distributionmentioning

confidence: 99%

“…Very few nodes are sources in the network and their characterization is trivial for vulnerability assessment [ Berardi et al ., ; Laucelli and Giustolisi , ]. In fact, in a network, the water source nodes represent special hubs, because the information departs from them, to be then transferred to the areas that they subtend.…”

Section: Network Connectivity For Classification Of Wdnsmentioning

confidence: 99%

Network structure classification and features of water distribution systems

Giustolisi

Simone

Ridolfi

2017

Water Resources Research

Self Cite

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The network connectivity structure of water distribution systems (WDSs) represents the domain where hydraulic processes occur, driving the emerging behavior of such systems, for example with respect to robustness and vulnerability. In complex network theory (CNT), a common way of classifying the network structure and connectivity is the association of the nodal degree distribution to specific probability distribution models, and during the last decades, researchers classified many real networks using the Poisson or Pareto distributions. In spite of the fact that degree‐based network classification could play a crucial role to assess WDS vulnerability, this task is not easy because the network structure of WDSs is strongly constrained by spatial characteristics of the environment where they are constructed. The consequence of these spatial constraints is that the nodal degree spans very small ranges in WDSs hindering a reliable classification by the standard approach based on the nodal degree distribution. This work investigates the classification of the network structure of 22 real WDSs, built in different environments, demonstrating that the Poisson distribution generally models the degree distributions very well. In order to overcome the problem of the reliable classification based on the standard nodal degree, we define the “neighborhood” degree, equal to the sum of the nodal degrees of the nearest topological neighbors (i.e., the adjacent nodes). This definition of “neighborhood” degree is consistent with the fact that the degree of a single node is not significant for analysis of WDSs.

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Assessing mechanical vulnerability in water distribution networks under multiple failures

Cited by 47 publications

References 32 publications

A Graph-Theoretic Framework for Assessing the Resilience of Sectorised Water Distribution Networks

A Graph-Theoretic Framework for Assessing the Resilience of Sectorised Water Distribution Networks

The Implication of Unreliable Urban Water Supply Service: The Case of Vendor Water Cost in Langata Sub County, Nairobi City, Kenya

Network structure classification and features of water distribution systems

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