MODELLING OF SEDIMENT TRANSPORT CAPACITIES OF OGBESE AND OWENA RIVERS IN SOUTH WESTERN NIGERIA

Abstract

The movement of sediment such as sand, silt or gravel by flowing water is of interest to a wide range of engineering disciplines. This study is aimed at developing models, which can be used to predict the magnitude and levels of sediment concentration in Ogbese and Owena Rivers in Ondo State. S W. Nigeria for engineering design purposes. Data were collected from field investigations conducted at the respective sampling stations on the two rivers. The live bed concept used was derived from Liu- Hwang (1954) resistance equations " and that of Einstein- Brown (1981) sediment transport concept. The problem was reduced to that of a power law relationship. These data were fitted into the power relationship to obtain the predicted model of the form; F1Q = k2θk1 where the parameters FIQ is the dimensionless sediment discharge θ is the dimensionless bed shear stress, k, and k 2 are sediment transport coefficients. Calibrating the models yielded the values of k1 and k2 for Ogbese river as 0.592 and 0.865 and for Owena river as 0.335 and 1.197 respectively. When tested, the predicted models for Ogbese and Owena rivers performed well in comparison with the established models such as Ackers and White (1973), Engelund and Hansen (1967), Yang (1973) and Karim (1998). It is concluded that the models developed would be useful for engineering design purposes for Ogbese and Owena rivers. These models which relate the sediment discharge, q, to the flow parameters, velocity, v, shear stress, t and the characteristic size of the sediments, d50 are: for Ogbese and Owena.