Why is Yan Guan Town in Haining the best place to watch the tide?

This is related to the special local topography. The place where Qiantang River enters the sea is called Hangzhou Bay. Hangzhou Bay is wide outside and narrow inside, forming a trumpet shape, and the width of Donggang is 100 km.

It is only 3 kilometers away from Yan Guan Town, Haining City in the west. At high tide, the tidal bore comes from the mouth of the bay and rushes to the west. Constrained by the narrowing banks on both sides of the strait, the water surface is getting narrower and narrower, the tidal bore is advancing, and the resistance is getting higher and higher, forming a surging spectacle.

The cause of spring tide

Time: from August 16 to August 18 in the lunar calendar, the sun, the moon and the earth are almost in a straight line, so the tidal force (the difference between the gravity of the moon, the sun or other celestial bodies on the earth and the gravity of the earth's unit mass, or the resultant force of the inertial centrifugal force generated by the earth's movement around the center of mass of the moon (sun) and the moon (sun))