Is it clear or clear?

When the tide is low, the sea is blue and clear. When the weather is bad or the spring tide, the sea water is yellow and turbid.

The most important representatives of muddy coast are Holland in Western Europe, Bohai Bay coast in China and south-central Jiangsu to north-central Fujian. Generally, these places have large river estuaries, and the sediment carried by the river keeps accumulating in the estuaries and coastal areas, and gradually forms a muddy coast under the scouring of waves for many years. In some places, the thickness of seabed silt even reaches 10 meter. Piles used by some fishermen in Zhejiang to fix fishing nets are deeply immersed in mud. They will find some thick bamboo, cut it into 6 meters long, hollow out the middle, and then smash it to the bottom of the sea with iron blocks weighing 700 to 800 kilograms. In this way, bamboo inserted in the mud at the bottom of the sea can last for many years and can withstand several tons of tension. This method is much more economical than throwing iron anchors directly. But this method can't be used in bedrock coast, sandy coast and biomass coast.