Is the bottom of a river covered in sild?

I dont know that's a good question

the bottom of the river is called a bed

At the riverbed, as it is called, are pebbles, sand, stones etc

Because it is the bottom and the bottom is a bed so river bed der u must understand it now

As the temperature drops, water contracts to the center. Also, because of density anomaly, the ice on top'll float on the bottom