A SIMPLIFIED METHOD FOR COMPUTING GENERAL SCOUR IN SAND-BED CHANNELS

摘要

A new quick method for computing general scour depth in sand-bed rivers is presented in this paper. The procedure is based on a series of hypotheses relating with the the cross section deformation in an initially stable channel, affected by the occurrence of a discharge increment. The concept of equilibrium velocity is analyzed taking into account this is the competent velocity necessary to maintain a generalized sediment flux of sand over the river bed during the peak of the flood. From this concept, a methodology to estimate the general scour in alluvial channels is presented, which is illustrated by a series of practical examples in which the method is applied to large sand-bed rivers, covering a wide range of characteristic hydraulic parameters. The reasonably good agreement between computed and observed scour depths is encouraging to continue the improvement and refinement of the proposed approach as a quick scour estimation tool.