ABSTRACT
ABSTRACT: The modelling of overbank flow is a technically challenging task due to the complexity of the 3-D flow structures that are present in most flooding rivers. As a result, there is a certain level of uncertainty in flood levels predicted by many numerical models. The development of a simple method for estimating the stage-discharge relationship for straight reaches of any river with a prismatic shape is described. It begins with initial concepts, based on data from experimental studies in the UK Flood Channel Facility, through to mathematical formulation, and then to their eventual inclusion in a software package, known as the Conveyance Estimation System. The method involves integration of the depth-averaged velocity field across the river, and includes the effects of bed shear, lateral shear and secondary flows. The model’s potential is illustrated by its application to a number of rivers world-wide.
