SEA WATER EXCHANGE TYPE BREAKWATER RESPONDING TO FLUCTUATION IN TIDAL LEVEL

摘要

PROBLEM TO BE SOLVED: To provide a sea water exchange type breakwater in response to fluctuation in tidal level with which sea water exchange inside and outside a port can be effectively performed even in a sea area where the tidal level fluctuates in a wide range. SOLUTION: An upright levee 2 having a headrace hole 5 in a lower portion and a submerged breakwater 3 with a channel-shaped plan view having its starting end and final end at the upright levee 2 located at the ocean side are provided, and a retarding area 4 surrounded by the submerged levee 3 and the upright levee 2 is formed. A recessed portion 7 is provided at the top 6 of the submerged breakwater 3 and a floating structural body 8 is housed inside the recessed portion. By the water level created by the retarding area 4 and a calm water area at the inner side of the upright levee, sea water inside and outside the port is exchanged through the headrace hole 5. The floated structural body 8 moves up and down following the fluctuation in tidal level, and the top 9 of the floated structural body 8 is always near the water surface. In this way, the wave breaking action of the submerged breakwater is accelerated regardless of the fluctuation in the tidal level thereby the difference in water level can be kept adequately and the sea water exchange can be performed effectively.