Surface water flooding risk to urban communities: Analysis of vulnerability, hazard and exposure

Developing appropriate responses to address and prevent surface water flooding requires an analysis of interactions between elements of a risk framework encompassing hazard, vulnerability and exposure. This paper explores the spatial distribution of surface water flooding, the vulnerability of communities to flooding, and the characteristics of physical environment and land use that affect people's exposure to flooding, particularly concerning green cover in Greater Manchester, UK. A set of 26 indicators known to influence the vulnerability of people to flooding was identified for spatial census units in Greater Manchester, and simplified with Principal Component Analysis to four underlying factors relating to material situation, diversity of communities and high proportion of children or elderly in the population. This was followed by an analysis of the presence and spatial distribution of surface water flooding areas, land use types, green cover and housing. Finally, the spatial associations between hazard, vulnerability and exposure were analysed. The results indicate that some of the most vulnerable people in Greater Manchester, namely the culturally diverse and materially deprived communities, are at high risk of flooding due to a convergence of factors related to socio-economic characteristics of the population, spatial distribution of the hazard, and the land use and housing types present in the area. Some adaptation responses tailored to the characteristics of the community and the environment they live in are discussed.

► Facets of vulnerability include poverty, cultural diversity, young and old age.
► The most diverse and the poorest communities are the most exposed to flooding.
► Poor housing and sealed surfaces increase the flood risk to these communities.
► Knowledge about vulnerability, hazard and exposure may help to address the risks.
► Responses associated with increased provision of green spaces are recommended.