Abstract
River mouth improvement of floodway of Ohya River flowing into the Shizuoka coast was investigated. This river mouth is located at the erosive coast and shoreline has been retreated for a long time. For the measures against beach erosion detached breakwaters have been built. Since northward longshore sand transport is predominant at this river mouth, sand accumulated at the mouth due to the accumulation effect of these detached breakwaters. In order to improve this condition, a method using submerged breakwater installed off the mouth was planed and numerical simulation was carried out to verify the usefulness of this method.
