Clear‐Water Scour around Abutments in Floodplains

Clear‐water scour around a bridge abutment in the floodplain of a compound channel was investigated. Experiments were conducted in a flume with a fixed‐bed main channel and a movable‐bed floodplain in which the abutment terminated. Flow depth, discharge, compound‐channel geometry, and abutment length were varied, and measurements of approach velocity distribution and scour depth were obtained. A preliminary relationship for the dimensionless scour depth is suggested to illustrate the compound‐channel effects on scour. The proposed relationship is limited to the range of values covered by the variables in this study.