Browsing by Author "Farmani, Raziyeh"

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    Battle of Postdisaster Response and Restoration
    (ASCE, 2020-06-10) Paez, Diego; Filion, Yves; Quintiliani, Claudia; Santopietro, Simone; Sweetapple, Chris; Meng, Fanlin; Farmani, Raziyeh; Fu, Guangtao; Butler, David; Zhang, Qingzhou; Zheng, Feifei; Diao, Kegong; Ulanicki, Bogumil; Huang, Yuan; Deuerlein, Jochen; Gilbert, Denis; Abraham, Edo; Piller, Olivier; Bałut, Alicja; Brodziak, Rafał; Bylka, Jędrzej; Zakrzewski, Przemysław; Li, Yuanzhe; Gao, Jinliang; Jian, Cai; Ou, Chenhao; Hu, Shiyuan; Sophocleous, Sophocles; Nikoloudi, Eirini; Mahmoud, Herman; Woodward, Kevin; Romano, Michele; Santonastaso, Giovanni Francesco; Creaco, Enrico; Di Nardo, Armando; Di Natale, Michele; Bibok, Attila; Salcedo, Camilo; Aguilar, Andrés; Cuero, Paula; González, Sebastián; Muñoz, Sergio; Pérez, Jorge; Posada, Alejandra; Robles, Juliana; Vargas, Kevin; Franchini, Marco; Galelli, Stefano; Kim, Joong Hoon; Iglesias-Rey, Pedro; Kapelan, Zoran; Saldarriaga, Juan; Savic, Dragan; Walski, Thomas
    The paper presents the results of the Battle of Post-Disaster Response and Restoration (BPDRR), presented in a special session at the 1st International WDSA/CCWI Joint Conference, held in Kingston, Ontario, in July 2018. The BPDRR problem focused on how to respond and restore water service after the occurrence of five earthquake scenarios that cause structural damage in a water distribution system. Participants were required to propose a prioritization schedule to fix the damages of each scenario while following restrictions on visibility/non visibility of damages. Each team/approach was evaluated against six performance criteria that included: 1) Time without supply for hospital/firefighting, 2) Rapidity of recovery, 3) Resilience loss, 4) Average time of no user service, 5) Number of users without service for 8 consecutive hours, and 6) Water loss. Three main types of approaches were identified from the submissions: 1) General purpose metaheuristic algorithms, 2) Greedy algorithms, and 3) Ranking-based prioritizations. All three approaches showed potential to solve the challenge efficiently. The results of the participants showed that, for this network, the impact of a large-diameter pipe failure on the network is more significant than several smaller pipes failures. The location of isolation valves and the size of hydraulic segments influenced the resilience of the system during emergencies. On average, the interruptions to water supply (hospitals and firefighting) varied considerably between solutions and emergency scenarios, highlighting the importance of private water storage for emergencies. The effects of damages and repair work were more noticeable during the peak demand periods (morning and noontime) than during the low-flow periods; and tank storage helped to preserve functionality of the network in the first few hours after a simulated event.
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    Global resilience analysis of water distribution systems
    (Elsevier, 2016-10-04) Diao, Kegong; Sweetapple, Chris; Farmani, Raziyeh; Fu, Guangtao; Ward, Sarah; Butler, David
    Evaluating and enhancing resilience in water infrastructure is a crucial step towards more sustainable urban water management. As a prerequisite to enhancing resilience, a detailed understanding is required of the inherent resilience of the underlying system. Differing from traditional risk analysis, here we propose a global resilience analysis (GRA) approach that shifts the objective from analysing multiple and unknown threats to analysing the more identifiable and measurable system responses to extreme conditions, i.e. potential failure modes. GRA aims to evaluate a system's resilience to a possible failure mode regardless of the causal threat(s) (known or unknown, external or internal). The method is applied to test the resilience of four water distribution systems (WDSs) with various features to three typical failure modes (pipe failure, excess demand, and substance intrusion). The study reveals GRA provides an overview of a water system's resilience to various failure modes. For each failure mode, it identifies the range of corresponding failure impacts and reveals extreme scenarios (e.g. the complete loss of water supply with only 5% pipe failure, or still meeting 80% of demand despite over 70% of pipes failing). GRA is also able to illustrate the similarities or differences in responses of different systems to various failure modes. Moreover, GRA reveals that increased resilience to one failure mode may decrease resilience to another and the same fraction of component failure could result in tremendously different level of failure impacts. The method can be used as a comprehensive diagnostic framework to evaluate a range of interventions for improving system resilience in future studies.
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    Modular interdependency analysis for water distribution systems
    (Elsevier, 2021-06-02) Diao, Kegong; Jung, Donghwi; Farmani, Raziyeh; Fu, Guangtao; Butler, David; Lansey, Kevin
    Complexity in water distribution systems (WDSs) poses a challenge for analysis and management of the systems. To reduce the complexity, the recent development of complex network science provides a system decomposition technique that converts a complex WDS with a large number of components into a simple system with a set of interconnected modules. Each module is a subsystem with stronger internal connections than external connections. Thus far, the topological features of the modular structure in WDS have been extensively studied but not the behavioural features, e.g. the hydraulic interdependencies among modules. Therefore, this paper aims to quantitatively measure and graphically visualize the module interdependency in WDSs, which helps understanding the behavioural complexity of WDSs and thus various WDS analyses, such as pipe maintenance, model calibration, rehabilitation, and District Metered Areas planning. Specifically, this study first identifies the WDS’s modular structure then measures how changes in the state of one module (i.e. any single pipe failure or perturbed demand within each module) affect the state of another module. Modular interdependencies are summarized in an interdependency matrix and visualized by the digraph. Four real-world systems are analysed, and three of them shows low interdependencies among most of the modules and there are only a few critical modules whose status changes will substantially affect a number of other modules. Hence, highly interconnected topologies may not result in strong and complex module interdependency, which is a fact that simplifies several WDS analysis for practical applications as discussed in this paper.
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    Optimal Rehabilitation of Water Distribution Systems using a Cluster-based Technique
    (ASCE, 2017-03-20) Muhmmed, Karwan; Farmani, Raziyeh; Behzadian, Kourosh; Diao, Kegong; Butler, David
    Optimal rehabilitation of large water distribution system (WDS) with many decision variables, is often time-consuming and computationally expensive. This paper presents a new optimal rehabilitation methodology for WDSs based on graph theory clustering concept. The methodology starts with partitioning the WDS based on its connectivity properties into a number of clusters (small sub-systems). Pipes which might have direct impact on system performance are identified and considered for rehabilitation problem. Three optimisation-based strategies are then considered for pipe rehabilitation in the clustered network: 1) rehabilitation of some of the pipes inside the clusters; 2) rehabilitation of pipes in the path supplying water to the clusters; 3) combination of strategies 1 and 2. In all optimisation strategies, the decision variables for rehabilitation problem are the diameters of duplicated pipes; the objective functions are to minimise the total cost of duplicated pipes and to minimise the number of nodes with pressure deficiency. The performance of proposed strategies was demonstrated in a large WDS with pressure deficiencies. The performance of these strategies were also compared to the full search space optimisation strategy and engineering judgement based optimisation strategy in which all pipes and selection of pipes are considered as decision variables respectively. The results show that strategy 3 is able to generate solutions with similar performance that are cheaper by around 53% and 35% in comparison with the full search space and engineering judgement based optimisation strategies respectively. The results also demonstrate that the cluster-based approach can reduce the computational efforts for achieving optimum solutions compared to the other optimization strategies.
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    Reliable, resilient and sustainable water management: the Safe & SuRe approach
    (Wiley Online Library, 2017-06-17) Butler, David; Ward, Sarah; Sweetapple, Chris; Astaraie‐Imani, Maryam; Diao, Kegong; Farmani, Raziyeh; Fu, Guangtao
    Global threats such as climate change, population growth, and rapid urbanization pose a huge future challenge to water management, and, to ensure the ongoing reliability, resilience and sustainability of service provision, a paradigm shift is required. This paper presents an overarching framework that supports the development of strategies for reliable provision of services while explicitly addressing the need for greater resilience to emerging threats, leading to more sustainable solutions. The framework logically relates global threats, the water system (in its broadest sense), impacts on system performance, and social, economic, and environmental consequences. It identifies multiple opportunities for intervention, illustrating how mitigation, adaptation, coping, and learning each address different elements of the framework. This provides greater clarity to decision makers and will enable better informed choices to be made. The framework facilitates four types of analysis and evaluation to support the development of reliable, resilient, and sustainable solutions: “top-down,” “bottom-up,” “middle based,” and “circular” and provides a clear, visual representation of how/when each may be used. In particular, the potential benefits of a middle-based analysis, which focuses on system failure modes and their impacts and enables the effects of unknown threats to be accounted for, are highlighted. The disparate themes of reliability, resilience and sustainability are also logically integrated and their relationships explored in terms of properties and performance. Although these latter two terms are often conflated in resilience and sustainability metrics, the argument is made in this work that the performance of a reliable, resilient, or sustainable system must be distinguished from the properties that enable this performance to be achieved.