Abstract
Protection in aprons of sabo dams is installed for the purpose of preventing scouring of the foundations by water falling from the waterway crown of the sabo dam, and to stabilize the level of the riverbed until the stream returns to the normal hydraulic state of river. In experimental research on the protection of aprons of the dams in the past, investigation was conducted under the condition that the crown of the counter dam is at the same elevation as the riverbed downstream, and the semi-theoretical applicability of the length of water hit and the height of the counter dam has been established. But ther are many sabo dams where the crown of the counter dam is situated higher than the riverbed. In this report, we will conduct an experiment that the riverbed is made the same height as the crown of the water hit, and the length of water hit and the height of counter dam are varied. The purpose being to determine an appropritate counter dam height and water hit lengh to balance the scouring downstream of counter dam.
