一、前言海水受月亮和太阳的引力产生潮汐,海岸水位每昼夜出现两次升降,是为海潮。入海河川下游受潮流影响,海水与河水相顶托,江河水位也在升降,是为江潮。当涨潮流速恰好与河水下泄的流速相抵,潮水停止倒灌,此处为潮流界。在潮流界以上潮水停止倒灌,但河水 I. INTRODUCTION Sea water is tidal by the gravitation of the moon and the sun. The coast water level rises and falls twice every day and night for the tide. Rivers downstream into the sea affected by the tide, seawater and water phase top support, the river level is also rising, is the tide. When the tidal current flows exactly in proportion to the flow rate of the river, the tidal water stops instilling. Here is the tidal current. In the trend of the tide over the world to stop intrusion, but the river