Local mud scour near a submerged wall is investigated experimentally.
　The experiments are carried out for two phases. The aim of the experiment-1 is to investigate erosion and deposition by waves and currents near a submerged wall. The experiment-2 deals with erosion at the tip of a submerged wall. Bottom materials used in this experiment are kaolinite, bentonite, and sand. Velocities are measured with a 2-channel laser-Doppler anemometer. In the experiment-1, a reverse current region is formed behind the submerged wall. The eroded bed materials are transported toward the submerged wall by the reverse current and no significant scour could be observed just near the submerged wall. In the experiment-2, erosion process is discussed with the measured shear stress and pressure originated in turbulence.