Abstract:
The transportation system is often considered a critical infrastructure as the failure of its components can have a
substantial impact on the economy and social well-being of a country. Extreme weather events such as urban
flooding disrupt transportation networks with delays, diversions, and partial or full closure of roads and, thereby,
influence human movement patterns. Most studies in the field of transportation network failure due to urban
flooding are focused only on micro-scale, in-situ approaches rather than referring to the holistic impact on the
entire transportation system. Moreover, such approaches are failed to address the changes in travel behaviour
concerning their trip purpose, mode choice, and income which can be changed due to inundation. Hence, this
study presents a novel approach to assess the entire transportation system failure due to urban flooding.
Consequently, the impact of urban flooding on human movement patterns was assessed. The proposed framework
is developed based on the network centrality measures, namely, betweenness centrality and closeness
centrality. The study is predominantly based on Open-Source GIS tools and the case study is carried out in
Colombo, Sri Lanka which has the highest concentration of population and transportation network. The hotspots
of the failure of the network were statistically and spatially illustrated. The study revealed three key findings; (a)
the fragmented network due to inundated road segments triggers the spatial changes in the accessibility,
particularly decreasing the accessibility in most of the core areas whereas increasing the accessibility in some
peripheral areas which are not significant under the baseline condition (2) the functional changes of the entire
transport network occurs due to flooding events (3) the considerable changes in the trip length occurs due to the
disruption of transport network links and the impact is mostly notable in long-distance trips compared to short
distance trips. The proposed framework can be utilized as a planning tool for both disaster practitioners and
infrastructure operators in identifying the flood risk; and prioritizing flood mitigation investments, thereby,
making the transportation system more robust to extreme flooding.
Citation:
Abenayake, C., Jayasinghe, A., Kalpana, H. N., Wijegunarathna, E. E., & Mahanama, P. K. S. (2022). An innovative approach to assess the impact of urban flooding: Modeling transportation system failure due to urban flooding. Applied Geography, 147, 102772. https://doi.org/10.1016/j.apgeog.2022.102772