Applicability of entropic velocity distributions in natural channel

Four different approaches to describe velocity profiles along verticals in natural channels and based on the entropic model have been investigated. Three of them consider a modified entropic formulation of velocity profiles, using different estimations of the entropic parameter, M. The fourth one uses the entropic formulation assuming a parabolic distribution of maximum velocities in flow area. Methods have been thoroughly investigated for low and high flow also for sampling condition of velocity points in the upper portion of the flow area. Two equipped hydrometric sites located along the Basento River, in Southern Italy, have been used as case study. A set of velocity measurements have been selected and methods reliability has been investigated in terms of percentage errors in estimating the mean velocity along each sampled vertical. It was found that the entropic model based on parabolic approach performed with similar accuracy of the other ones, showing that it can be conveniently applied for high flow conditions, when velocity points sampling is difficult in lower flow area.