Simple Methods for Direct Computation of Bed Roughness due to Sediment Transport

The aim of this technical note is to present methods that allow for direct computation of the bed roughness due to sediment transport based on a formula developed in the literature for cases involving current or waves separately. The methods result in approximate nondimensional expressions for the exact solutions in terms of polynomials determined by least-square fits, where the accuracy of the polynomials is high. Using the present methods may significantly reduce calculation times of roughness due to sediment transport in numerical models of morphological change.