M. A. Khalifa^1,, Kh. A. Zahra²

Hydraulic structures cause disturbances in uniform flow and sediment transport. Downstream of these structures flow velocities increase due to constriction of the channel. Bed protection is often constructed in order to decrease the maximum scour hole and to shift the scour holes that involve a potential risk to structural stability to a greater distance from the hydraulic structure. Both hydraulic and geotechnical characteristics influence these two design parameters and are treated in more detail in subsequent sub-sections. Attention is paid to the processes relevant to sedimentation and consolidation, because these affect the erosion behavior of beds with cohesive sediments. The scour which may occur near a structure can be considered to be a result of bed scour caused by different processes. Owing to shear failures or flow slides, the scour process may progressively damage the bed protection. This will lead to the failure of hydraulic structures. The paper also discussed the effects of the angle of wave attack on coastal areas formation and the effect of wave attack angle variation on the sediment transport rates.

sediment trans-port, decrease the scour hole, erosion behavior of beds