Condition that leads to formation of silt at the mouth of a river

When rock is eroded or worn away by water or ice. As the water carries tiny rock splinters they scrape against the bottom of the river bed carrying along more tiny bits. This is what causes the formation of silt at the mouth of a river.

моля да ми помогне с английски език аз не разбирам

molya da mi pomogne s angliĭski ezik az ne razbiram