没入

Hills melt into the sky.

群山渐渐没入天际。

From some field investigations (like Lake Constance and Lake Mead), the shape of a delta is not a Gilbert delta.Slope evolution between foreset and bottomset is not sharp but smooth.

当河川流入湖或水库，若河川密度是高于湖，河川就会没入湖形成异重流。