Estimating Average Velocity in Cobble-Bed Channels

A data set obtained from natural channels having D//5//0 less than 64 mm and d/D//5//0 in the range of 3 to 20 is used as a basis for testing equations proposed by Limerinos, Thompson and Campbell, and Bathurst for this class of channel. The distribution of values of the Strickler coefficient for estimating Manning's n is presented. Best-fit equations indicate that there is little value in using a measure of bed material size for this range of flow conditions.