Development of Gravity Drainage System for Beach Protection

摘要

Beaches in Japan have chronically suffered from erosion problems for more than forty years owing to the decrease of sediment supply from rivers and interference with longshore sediment transport by coastal structures. As a result, for beach protection, many coastal structures such as groins, detached breakwaters and seawalls have been constructed, and these work effectively from the viewpoint of disaster prevention. However, the structures keep people from accessing beaches even under mild wave conditions, and deteriorate valuable landscape. Therefore we developed a new beach protection system with gravity drainage, which has no structures on a beach.