Geophysical assessment of flood vulnerability of Accra Metropolitan Area, Ghana

Abstract

In light of Ghana’s exploding population, rapid urbanization, and the imminent threat of climate change, urban flooding is a severe and increasing developmental concern. This study was conducted against the proposition that without anthropogenic factors, geophysical factors drive flooding within Accra Metropolitan Area. This study assessed spatial patterns of flood vulnerability using geophysical variables. The spatial analytical technique of weighted overlays was applied to ascertain the spatial variation of flood vulnerability. Based on geophysical variables, the study finds that only 71% of the metropolis is highly susceptible to flooding. Overlay of geophysical flood vulnerability map with residential neighbourhoods, the results correlated with known vulnerable areas. Three hazard level categories—high, medium, and low—have been established for the flood risk areas. Suburbs with a high or moderate risk of flooding necessitate more sophisticated engineering safe guards. The analysis also found that areas with medium and high incomes are becoming more vulnerable to flooding. The study proposes that efforts at flood control must focus on proper physical planning, stringent development control, elimination of drainage network flaws, and limiting the city’s lateral expansion.