ABSTRACT Thorough understanding of the rainfall-runoff processes that influence watershed hydrological response is important and can be incorporated into the planning and management of water resources. This study assessed rainfallrunoff models through inferential statistics and benchmarked their runoff predictive accuracies against a proposed new runoff model. Linear regression model has been in use to model urban rainfall-runoff. However, the model was found to be statistically in-significant in this study. Hydrological implications from the regression model became in-consistent and obsolete. The 1954 simplified SCS runoff model was also statistical in-significant under two Null hypotheses rejection and paved way for the regional model calibration study. A new rainfall-runoff model was developed with calibration according to regional hydrological conditions. It out-performed simplified SCS runoff model and reduced RSS by 54%
