Abstract

Abstract – This study developed a quantitative approach for the morphodynamic assessment of River Niger at Lokoja. The study involves the collection of twenty-one years daily discharge and water level at the gauging station. The data were collated and outliers were removed. The missing data were fitted using the Least Square Method. The flood generating processes were investigated by computing the bankfull discharge of selected reach as well as collecting river bed samples at six (6) different locations along the river reach. Based on these, the specific gravity and mobile D50 and D90 of the bed materials were obtained. The preliminary investigation of the river morphodynamics was studied by computing the sediment transport parameters such as Shield parameter, bed shear velocity, sediment fall velocity amongst others. These parameters are significantly important due the high flow rate associated with the river. Based on criteria by two well-known sediment transport capacity formula, the river reach is characterized as sandy-bed River in line with Eugelund and Hansen’s Formula (E-H-F). The entire flow generation parameters and mobile river bed materials failed the Meyer and Peter- Muller criteria. Hence, the sediment transport capacity of the river was computed using (E-H-F). The results show that understanding the morphodynamics of the rivers play a significant role in the understanding of flooding.

Key words: Keywords – morphodynsmic, River Niger, specific gravity, sediment transport