Prediction of Maximum Scour Depth at Bed Sills

Bed sills are sometimes built to limit the amount of material eroded from degrading streams. The construction of these structures leads to the development of local scour downstream of them. The maximum scour depth was evaluated in the past by the authors under the conditions of no sediment feed and uniform bed material. They used two distinct grain sizes, obtaining an empirical non-dimensional formula. Here a new series of experimental results obtained in a flume with different side wall roughness and using finer bed material is presented. Those results confirm that the scour depth can be expressed as a simple function of the properties of the stream and the sediments.