Local impacts on road networks and access to critical locations during extreme floods

TL;DR

This paper introduces a novel approach to assess local impacts of extreme floods on road networks by focusing on accessibility of towns rather than traditional connectivity measures, aiding better risk management.

Contribution

It proposes a new method for evaluating flood impacts on transportation by partitioning networks based on local accessibility, moving beyond percolation-based models.

Findings

Identifies cities crucial for providing critical services during floods.

Highlights limitations of giant connected component in flood resilience analysis.

Provides a practical framework for resource allocation during flood events.

Abstract

Floods affected more than 2 billion people worldwide from 1998 to 2017 and their occurrence is expected to increase due to climate warming, population growth and rapid urbanization. Recent approaches for understanding the resilience of transportation networks when facing floods mostly use the framework of percolation but we show here on a realistic high-resolution flood simulation that it is inadequate. Indeed, the giant connected component is not relevant and instead, we propose to partition the road network in terms of accessibility of local towns and define new measures that characterize the impact of the flooding event. Our analysis allows to identify cities that will be pivotal during the flooding by providing to a large number of individuals critical services such as hospitalization services, food supply, etc. This approach is particularly relevant for practical risk management and will help decision makers for allocating resources in space and time.