Indirect flood impacts and cascade risk across interdependent linear infrastructures
Indirect flood impacts and cascade risk across interdependent linear infrastructures
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DOI：
10.5194/nhess-2020-371
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发表时间：
2020-11
影响因子：
4.6
通讯作者：
C. Arrighi;M. Pregnolato;F. Castelli
中科院分区：
文献类型：
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作者：
C. Arrighi;M. Pregnolato;F. Castelli
抽象。洪水是世界上最常见和最具破坏性的自然威胁之一。虽然对直接影响的评估进展顺利，但对间接影响的评估却很少实现。间接影响不是由于与洪水的实际接触，而是由于基础设施性能下降等原因造成的。线性关键基础设施（如道路和管道）具有相互关联的性质，可能导致故障传播，因此影响远远超出淹没地区和/或时间。本文对两个线性基础设施系统，即供水系统和道路网络系统进行了风险分析。间接洪水对两个网络的影响进行了评估的四个洪水的情况下，得到一个耦合的一维准二维水力模型。两种方法被用来评估的WSS和道路网络上的影响：压力驱动的需求网络模型和交通网络中断模型。分析的重点是确定（一）共同的影响指标，（二）易受洪水影响的因素，（三）两个网络的方法方面的相似性和差异，以及（四）由于系统的相互依赖性的风险。这项研究提出了一个应用程序的大都市区的佛罗伦萨（意大利）。当考虑到相互依赖性时，结果表明，如果分别在60分钟和120分钟内完成对WSS站的及时维修，则WSS的人口当量（PE/年）风险可降低71.5%和41.8%;管道长度（km/yr−1）对WSS的风险可降低53.1%和15.6%。该研究强调，系统性的风险知情规划可增强复原力，确保对关键基础设施进行及时干预;然而，对于间接影响和级联效应，时间和空间尺度难以界定。通过对多个城市基础设施进行系统风险分析，前景研究可以进一步改进这项工作。
Abstract. Floods are one of the most frequent and damaging natural threats worldwide. Whereas the assessment of direct impacts is well advanced, the evaluation of indirect impacts is less frequently achieved. Indirect impacts are not due to the physical contact with flood water but result, for example, from the reduced performance of infrastructures. Linear critical infrastructures (such as roads and pipes) have an interconnected nature that may lead to failure propagation, so that impacts extend far beyond the inundated areas and/or period. This work presents the risk analysis of two linear infrastructure systems, i.e. the water distribution system (WSS) and the road network system. The evaluation of indirect flood impacts on the two networks is carried out for four flooding scenarios, obtained by a coupled 1D–quasi-2D hydraulic model. Two methods are used for assessing the impacts on the WSS and on the road network: a pressure-driven demand network model and a transport network disruption model respectively. The analysis is focused on the identification of (i) common impact metrics, (ii) vulnerable elements exposed to the flood, (iii) similarities and differences of the methodological aspects for the two networks, and (iv) risks due to systemic interdependency. The study presents an application to the metropolitan area of Florence (Italy). When interdependencies are accounted for, results showed that the risk to the WSS in terms of population equivalent (PE/year) can be reduced by 71.5 % and 41.8 %, if timely repairs to the WSS stations are accomplished by 60 and 120 min respectively; the risk to WSS in terms of pipe length (km yr−1) reduces by 53.1 % and 15.6 %. The study highlights that resilience is enhanced by systemic risk-informed planning, which ensures timely interventions on critical infrastructures; however, for indirect impacts and cascade effects, temporal and spatial scales are difficult to define. Perspective research could further improve this work by applying a system-risk analysis to multiple urban infrastructures.