Abstract
Field observations have been carried out to investigate on splash height and overtopping rate of block mound seawall at the Oyashirazu Coast in Niigata Prefecture. Splash heights were measured by using video camera system. Velocities and depths of a overtopping flow were directly measured by electro-magnetic current meter and ultrasonic-type elevation meter. The main results are in the followings: Relative heights of a splash depend on the relative crown height (hc/Ho) and deepwater wave steepness. They increase their values as the relative crown height become large, whereas the deepwater wave steepness become small. Standard deviations of splash height amount to about 25% of the mean value. The maximum velocities of overtopping flow reach from 6m/s to 8m/s with a depth of 5cm to 20cm. The peak values of overtopping rate measured amount to larger than 0.2m3/s/m.
