EFFECTIVENESS OF JETTY CONSTRUCTION AT THE SHIRIBETSU RIVER MOUTH, JAPAN

摘要

At the Shiribetsu River mouth located in Hokkaido, Japan, a jetty was constructed on the right hand side of the mouth from July to October 1999. In this study, the consequence of the jetty construction is studied by analyzing field data of river mouth morphology and water level variation. Before jetty construction, water level rise due to wave set-up was frequently observed every year from October to March (Tanaka and Lee, 2001). It is found that the height of wave set-up increased in winter with the development of a sand spit at the river mouth. After placement of the jetty, it is confirmed that the interruption of longshore sediment movement led to stability of the river mouth opening. Furthermore, it caused reduction of wave set-up in the river mouth.