DAMAGE FROM LONG SWELL TO COASTAL PROTECTION FACILITIES IN A FISHING PORT AREA AND ITS EFFECT ON DESIGN OFFSHORE WAVES

Abstract

 This paper investigated the influence of swells on design waves through the analysis of observed wave data and case studies of actual swell-induced damages of coastal protection structures around fishing port of Japan. As a result, it was found that the effect of swells on the design offshore waves is relatively insignificant on Japan Sea side except a part of Hokuriku region, three major bays in Japan (Tokyo, Osaka and Ise bays), and the Seto Inland Sea. On the Pacific Ocean side, the influence of swell waves was significant. However, it was also found that the influence of swells is partially accounted for in the recently reevaluated design waves obtained through the extreme value statistical analysis based on the wave data including recent swell events. In addition, an attempt was made to reproduce a case of damage caused by long period swell, and it was found that the observed damages can be reasonably explined by the wave and current field in the vicinity of the structure computed by the Boussinesq-type wave model and CADMAS-SURF/2D.