QUANTITATIVE EVALUATION OF REDUCTION EFFECT OF LONGSHORE SAND TRANSPORT BY GROINS ON DYNAMICALLY EQUILIBRIUM COAST

Abstract

 Beach changes when groins with various shapes were installed on a dynamically equilibrium coast with a constant rate of longshore sand transport were investigated using the contour-line change model. First, the Numakawa-daini floodway on the Fuji coast was taken as an example of the beach changes around a groin installed on a steep coast, and beach changes were reproduced using the contour-line change model. Then, the relationship among the length of the groin, its point depth and longshore sand transport was investigated together with the study on the difference between L-shape groin and a single groin. Moreover, the difference in the function of a single groin and L-shape groin to be installed on the Shimizu coast was studied by the same model.