Field survey on wave overtopping was carried out at Fukui port during winter season in 1996. Water depth in wave dranage channel between the walls which sectioned the wave dranage channel was measured during the wave overtopping. Overtopping rate was estimated by two ways: Rate of volume change to the time and the discharge formula over surpressed weir using the water depth of overflow. The significant wave height 6.1m with its wave period 11.6s resulted in the mean overtopping rate of 10-4m3/s/m in the order of magnitude. Overtopping rate due to wave group is also estimated to be about ten times the mean overtopping rate. The mean overttoping rate are compared with estimated ones using the experimental formula by Takayama et al.(1972).
