|
Journal of Environmental Hydrology
ISSN 1058-3912 |
||
|
Electronic Journal of the International Association for
Environmental Hydrology
JEH Volume 18 (2010), Paper 25 Posted December 28, 2010 FLOOD ROUTING IN THE OGUNPA RIVER IN NIGERIA USING HEC-RAS
P.O. Adewale1,3 2Department of Agricultural & Environmental Engineering, University of Ibadan, Ibadan, Nigeria 3Department of Bioresource Engineering, McGill University, Ste-Anne-De-Bellevue, QC, Canada ABSTRACT The HEC-RAS (Hydrologic Engineering Center - River Analysis System) modeling framework was used to evaluate both the flood routing and water flow activity of the Ogunpa River, one of the largest rivers running through Oyo state, Nigeria, situated in the densely-populated town of Ibadan. The river is significantly affected by its urban location, with the majority of its annual flood events resulting from direct human activity and urban interference. The river channel is the depository for an alarming amount of sewage, domestic, hospital and industrial wastes. The poor waste disposal habits within Ibadan are directly linked to the frequent flooding of the river, especially at downstream reaches. A single data entry of river channel geometry and flow into the HEC-RAS computer program is sufficient to model steady flow, unsteady flow, water surface profiles, sediment transport/movable boundary computations, and water quality. This study focused on the modeling of the steady flow water surface profile and the following results were obtained: the discharge of the 50 yr profile was 1.87 m3/s while that of the 100-year profile was 2.8 m3/s. The discharge was roughly constant between the distances of 1.21 - 2.02 km along the channel. The discharge was directly proportional to the stream length (between 7.9 km and 11 km). The volume of the 50-year profile was 3.76 x 105 m3 while that of the 100-year profile was 4.82 x 105 m3 in the lower course of the Ogunpa River. The difference between the 50-year and 100-year profiles results confirmed the urbanization in this region, which leads to increases in runoff and chemical and waste pollution. The channel velocity in the lower course tends to zero, which is a result of the stagnant nature of the river in the lower course due to the accumulation of heavy refuse. This particular region of the river channel is susceptible to flooding during peak rainfalls. Reference: Adewale, P.O., A.Y. Sangodoyin, and J. Adamowski. 2010. Flood routing in the Ogunpa River in Nigeria using HEC-RAS. Journal of Environmental Hydrology, Vol. 18, Paper 25. CONTACT: Jan Adamowski Faculty of Agricultural & Environmental Sciences McGill University Macdonald Campus Ste-Anne-de-Bellevue Québec H9X 3V9 E-mail: jan.adamowski@mcgill.ca |
||
|
Return to JEH 2010 Papers
Return to HydroWeb Homepage |
||