SEA WATER-CROSSED BREAKWATER

PURPOSE:To prevent the propagation of wave pressure to the inside of a port for activating the action of automatic depuration by providing a breakwater having a water storage tank opened toward the outside of a port and a water conveyance path opened toward the bottom inside the port. CONSTITUTION:By introducing overflow water 10 of tidal wave 9 outside of a port 3 through a water conveyance path 12 into the port 4 by water head H produced in a water storage tank 11 by means of a breakwater 1, the direct propagation of wave pressure to the inside of the port 4 can be avoided. The dissolved oxygen amount in sea water is increased by the turbulent flow of the tidal waves 9 coming into the tank 11, the overflow water 10 with rich dissolved oxygen flows into the bottom layer in the port 4 to form an aerobic state, and thereby the automatic depuration of sea water is activated. Also, in the summer season, the overflow water of the tidal waves in high-temperature surface layer flows into the low-temperature bottom layer in the port 4 to form a convectional flow in the vertical direction in the port 4, and the crossing of sea water in the port 4 is accelerated.