One-Dimensional Hydraulic Modelling of River Ona Bridges, Ibadan, South-Western Nigeria

Bridges are crucial for transporting people and goods, but their failures can be catastrophic, resulting in loss of life property. This study assessed the flood stage selected bridges (Alaafin Avenue, Seven-Up, Oluyole) along Ona River, Ibadan, Nigeria, using a one-dimensional model called Hydraulic Engineering Center-River Analysis System (HEC-RAS). The requires two major input data: geometric steady flow data. features area (stream centerline, riverbanks, paths, cross-sections, bridges) were generated from Digital Elevation Model (DEM) HEC-GeoRAS, an extension ArcMap GIS. MapWindow Soil Water Assessment Tool (MWSWAT) was used to predict flow. data include DEM, Land use, soil map data, meteorological obtained Nigerian Meteorological Agency (NIMET). stages three predicted HEC-RAS results showed that Alaafin Seven-Up Oluyole had 1.5 m, 1.6 2.5 m freeboard minimum clearance 2 0.3 0.5 respectively. However, (75.25 m³/s) compared with corresponding value ERA (2002) free board clearance. It shown only Avenue Bridge is safe while prone inundation by approximated values Therefore, regular inspection maintenance recommended prevent inundation.