HYDROLOGICAL STUDY OF OGUN RIVER

Abstract

Hydrological study of Ogun River, Nigeria was carried out from the available rainfall and discharge data of year 2000 to 2016 with the aim of providing necessary information for maximum utilization of the River. Data were obtained from Hydrology Department of Ogun-Oshun River Basin Authority for the studies. From the Rainfall and discharge data obtained, annual mean rainfall, Point rainfall, Moving average, Mass curve and flood frequency analyses were carried out. Models such as Gumbel distribution, Powell distribution and Log Pearson type III models were used for flood frequency analysis of Ogun River. From the Flood frequency analysis, maximum flood discharge was calculated for the recurrence interval of 10, 25, 50, 100 and 200 years for each model. The Gumbel model analysis gave the calculated results for 10years, 25years, 50years, 100years and 200years to be 567.3074m3/s, 713.1796m3/s, 821.3634m3/s, 928.7465m3/s, and 1035.753m3/s respectively while Log pearson type III was 578.76m3/s, 691.35m3/s, 758.93 m3/s, 813.77 m3/s and 859.01 m3/s respectively and Powell distribution model was 353.5457m3/s, 469.5920m3/s, 555.6759m3/s, 641.1304m3/s, and 726.2709m3/s respectively. Microsoft Excel was used for the analyses. The digitization of settlement around the Ogun River was carried out using Google earth image to show the ecological map of Ogun River while digital elevation model (DEM) was used for River Basin generation. ARCGIS 10.3 Version was used to generate GIS maps for Ogun River, the River basin and land use cover of the River. In this research, flow duration curve was developed for Ogun River. The Research work has contributed technically to the knowledge of hydrology of Ogun River on which government and private agencies can depend for the maximal utilization of the River. The research has also established useful models for usage in water resources projects in Ogun River