Mapping Flood Vulnerability in Low-Income Settlements of Port Harcourt, Rivers State

Flooding constitutes one of the most recurring environmental hazards affecting urban communities across Nigeria's South South geopolitical zone, with Port Harcourt experiencing increasing inundation events linked to inadequate drainage, coastal proximity, and poor urban planning. This study maps flood vulnerability across five low-income settlements in Port Harcourt using a composite vulnerability index that integrates physical exposure, socio-economic sensitivity, and adaptive capacity indicators. Primary data were collected through structured interviews with 200 households, field measurement of drainage infrastructure, and GPS-based mapping of flood-prone zones. Secondary data included ten-year rainfall records from the Nigerian Meteorological Agency and satellite-derived elevation data. Results indicate that Diobu, Rumuola, and Borokiri settlements exhibit the highest vulnerability scores, attributable to poorly maintained storm drains, high population density, and low household income levels. Women-headed households and households without formal property ownership are identified as disproportionately vulnerable sub-groups. The study recommends targeted investment in drainage rehabilitation, community-based early warning systems, and integration of flood risk mapping into Port Harcourt's master plan revision. The composite index developed offers a replicable methodological framework applicable to other Nigerian coastal cities. Keywords: flood vulnerability, low-income settlements, Port Harcourt, drainage infrastructure, urban hazard mapping.