RIVER MOUTH IMPROVEMENT USING AN ARTIFICIAL REEF TO REDUCE BERM HEIGHT OF RIVER MOUTH BAR

The contour line change model was applied to predict the beach changes around artificial reefs built on the Shichiri-Mihama coast composed of coarse materials and facing the Pacific Ocean. The formation of a salient behind an artificial reef was reproduced well. On the basis of this numerical simulation, the model was further applied to the investigation of the improvement of the mouth of the Shihara River flowing into the same coast. In front of the mouth, an artificial reef is built to reduce the berm height. The appropriateness of this method in the reduction of the berm height, which is necessary for creation of a floodway, was confirmed by numerical simulation, if parallel jetties are further built to the shoreline to obstruct longshore sand transport on the shore face.