Accuracy of Equivalent Roughness Height Formulas in Practical Applications

Abstract

This paper presents a discussion on the application and accuracy of roughness height formulas from a practical point of view. Such formulas have been proposed to describe the equivalent roughness height for plane bed conditions on the basis of the Shields parameter. The application of these relationships requires an iterative solution technique. However, as this paper demonstrates, the roughness estimates are not always reliable because the application of the formulas yields large discrepancies in the results.