Abstract
Beach changes around Shinkawa fishery harbor in Niigata Prefecture were investigated by using beach survey data since 1985. At this coast river mouth jetties were built at the Shinkawa River and Shinkawa fishery harbor originally located inside the river mouth was enlarged to widen mooring site. To this purpose new breakwaters of the outer harbor were built. Southward longshore sand transport dominating on this coast was obstructed by these breakwaters to cause beach erosion on the downcoast. In order to solve this problem sand bypassing is required.
