Discussion of 'Unifying Criterion for the Velocity Reversal Hypothesis in Gravel-Bed Rivers' by D. Caamano, P. Goodwin, J. M. Buffington, J. C. P. Liou, and S. Daley-Laursen

摘要

The authors present a criterion to distinguish pool-riffle sequences in which a velocity reversal occurs from those in which it does not. This would explain the variability that has been found among various studies on the hydraulics of pools and riffles and allow an assessment as to whether the velocity reversal phenomenon is significant for the formation and maintenance of pools in gravel-bed rivers. The criterion is based on the mass and energy conservation equations calculated at two cross sections-one in the pool and the other in the riffle. The application of the criterion to several data sets appears to distinguish the presence/absence of velocity reversal based on the section-averaged velocity.