Citation

Papilloud T, Röthlisberger V, Loreti S, Keiler M. Int. J. Disaster Risk Reduct. 2020; 47: e101548.

Copyright

(Copyright © 2020, Elsevier Publishing)

DOI

10.1016/j.ijdrr.2020.101548

PMID

unavailable

Abstract

Assessing the flood exposure of infrastructure is crucial for sustainable flood risk management. We propose to define road exposure to floods as "any road segment/element located within a flood hazard zone". On the example of Switzerland, we develop and compare three methods to assess the flood exposure of the road infrastructure: absolute road area potentially flooded (method A), relative road area potentially flooded (method B), and a network-based approach using the edge betweenness centrality index (method C). The results are aggregated and ranked in grid cells of 2 km by 2 km for comparison. The ranks are directly proportional to exposure levels. The results present distinct spatial patterns; grid cells with higher values in method A indicate where more road surfaces are in a flood hazard zone (urban or high road density areas in flood plains), while method B highlights where most of the road surface is in flood hazard zones of predominantly mountainous areas of Switzerland. Higher values in method C present areas where the most-connected road links within a network are exposed to floods. Most of the grid cells that have higher values in method B than in method C indicate isolated mountain valleys that can be accessed only by a single road exposed to floods. The study demonstrates the importance of an appropriate choice of methods in flood exposure analysis. As exposure analysis is a key step in flood risk assessment, the presented results provide information essential for decision making in disaster risk reduction.

Language: en

Keywords

Edge betweenness centrality; Flood exposure; Road area; Road network; Spatial comparison; Spatial network analysis