Enhancement of large-scale flood risk assessments using building-material-based vulnerability curves for an object-based approach in urban and rural areas

Abstract

Abstract. In this study, we developed an enhanced approach for\nlarge-scale flood damage and risk assessments that uses characteristics of\nbuildings and the built environment as object-based information to represent\nexposure and vulnerability to flooding. Most current large-scale assessments\nuse an aggregated land-use category to represent the exposure, treating all\nexposed elements the same. For large areas where previously only coarse\ninformation existed such as in Africa, more detailed exposure data are\nbecoming available. For our approach, a direct relation between the\nconstruction type and building material of the exposed elements is used to\ndevelop vulnerability curves. We further present a method to differentiate\nflood risk in urban and rural areas based on characteristics of the built\nenvironment. We applied the model to Ethiopia and found that rural flood\nrisk accounts for about 22\u2009% of simulated damage; rural damage is\ngenerally neglected in the typical land-use-based damage models, particularly at this scale. Our approach is particularly interesting for studies in areas\nwhere there is a large variation in construction types in the building\nstock, such as developing countries.