DERIVATION OF EQUATIONS TO PREDICT SHEAR STRESS AND EROSION RATE OF GULLY EROSION SITE IN OGUN STATE, SOUTH WESTERN, NIGERIA

Abstract

The serious effects of erosion constitute a real environmental challenge that should not be underestimated. This study investigated the functional relationships of shear stress, discharge, channel characteristics and erosion rate estimation models. The length, depth and width of the channel were measured and other hydraulic parameters were derived from the measurements. The shear stress Ï„ is taken as the important factor measuring the power of the flow to discharge the sediment. Simple regression analysis was applied to the three computed values of shear stress, Ï„, discharge Q and erosion rate E according to their functional relationships. The predicted values were subjected to scatter plot and various trend lines and equations were obtained. The results of this study indicate that there was an explanatory independent variable for discharge in predicting shear stress with a coefficient of determination r²=85% and also the results of erosion rate prediction of r² of 97% and 99% respectively. The equations established for shear stress and erosion rate prediction are power and 3^rd degree polynomial equation that can be useful and essential to the development of sound sediment management plans and formulation of policies.