Toru HASHIMOTO
Basic study for clarify seashore accident caused by rip current at Niigata coast.
Tokuzo HOSOYAMADA
In late years, demand of marine recreation increased and it is enjoyed by many people in Japan. However, many seashore accidents occurred during swimming activity caused by many factors. One of them is rip current. Rip current is strong flow with the direction toward offshore which can be caused by the shape of seafloor topography.
During last few years, rip current caused by an artificial shore structure is pointed one of the possibility. As the number of artificial structure increase, rip current is also increase.
This study is performed to investigate rip current of the vicinity of shore structures at Niigata Prefecture. At Niigata coast, the direction of main incident wave varies from North to Northwest. It was confirmed that, the seashore accidents usually at the change of wave height and periods.
The observation locations are Niigata Fishing Port side around a jetty at Shiiya Kashiwasaki City and at Osaki Beach. At Niigata Fishing Port side, rip current around jetty of Shiiya travels toward offshore with the distance about 200 meters and maximum velocity is 0.97 m/s. While at the Osaki Beach, there was circular flow with the diameter about 60 meters and the maximum velocity is about 1.38 m/s.
As for this study, a scale and an developmental processes became clear in two shores.
Please use "previous botton" to return the previous page