Analysis of Waste Dumping Along Drainage Channels and Its Effect on Urban Flooding in Aba, Abia State

Indiscriminate waste dumping in urban drainage channels is a pervasive problem in Nigerian commercial cities that exacerbates flood risk by reducing hydraulic capacity and increasing runoff volumes during storm events. This study analyses the relationship between waste dumping in drainage channels and urban flooding frequency in Aba, Abia State, a major commercial hub in the South East. Drainage channel surveys were conducted along 28 kilometres of primary and secondary drains in five of the most flood-prone wards, measuring channel cross-sectional areas and quantifying solid waste deposits by volume and composition. Flood incident records from the Abia State Emergency Management Agency for the period 2018 to 2024 were spatially matched with drainage survey data. Household surveys involving 175 respondents captured flood experience, property loss estimates, and waste disposal behaviour. Findings demonstrate a strong spatial correlation between drainage channel obstruction by solid waste and flood inundation frequency, with channels recording the highest obstruction ratios associated with four to six flooding events per wet season. Polythene bags, plastic bottles, and styrofoam constitute over 70 percent of drain-blocking materials by count. Households along inadequately maintained drains report annual flood damage costs averaging 85,000 Naira. The study recommends regular mechanical drain de-silting and waste removal, strategic placement of litter traps at drain inlets, and community engagement campaigns targeting plastic waste reduction. Keywords: waste dumping, drainage channels, urban flooding, Aba, flood risk management.