Considering the influence of retrogressive erosion on total scour at underwater structure, the study of scour evolution and prediction was conducted to provide a reference to the flood protection of structure. Based on the flume experiments,the evolution and influential factors of retrogressive and local scourwere observed. In addition,a time-dependent calculation method was proposed for the coupling scour. Theratio of local scour with or without retrogressive erosion varies with the distance between the pi...