Scouring downstream of hydraulic structures is one of the critical phenomena for the design criteria and sustainable management of the hydraulic structures which has absorbed a vast amount of interests by researchers. This study presents the results of various experiments conducted at three different stepped spillways, to study the local scour downstream of the structure. Experimental tests performed with different discharges (flow regimes) and three various step size. The results indicated that step size as a geometrical factors and tailwater depth and discharge as flow characteristics are essential parameters for maximum scouring depth. The dimensions of scour pit decreased by increasing the steps height and tailwater depth. It was further shown that the maximum scour corresponds to the skimming flow regime. By increasing the discharge, the increased momentum of the flow promotes scouring. In addition, the results show that scouring at the sidewalls is higher than in the middle of the cross-section.
