Urban storm drainage is a network of closed or open conduits that receive runoff from inlets or surfaces, and conveys it to an outfall or downstream outlet. Drainage plays a very important role in evacuating stormwater from cities thereby reducing the possibilities of flood. This study examined the features of urban storm drainage in Aba, Nigeria. The study adopted geometric survey technique, and relied mainly on primary data which were collected through direct observation and measurements. Data collected were analyzed with appropriate parametric tests using SPSS for Windows, Version 17. Specifically, Analysis of Variance (ANOVA) was used to test the hypothesis of the study. Findings show that the geometries of the drains are characterised by structural deficiencies in terms of low hydraulic capacities, low invert grades, narrow wall thicknesses, incompletion, no systemization and lack of downstream outlets, which significantly contribute to urban flooding in Aba. The study recommends among other things, that the government of Abia State should plan for, and produce urban drainage master plan for the city of Aba, which will ensure the provision of standardized arteries and network of infrastructure for stormwater conveyance and treatment.
