shallow

Shallow is an elevation of the bottom in the sea, river, lake, which impedes navigation. It is a type of an underwater relief where the depth of the water is low compared to that of the surrounding points. Usually formed by sand or pebble deposits, can also be of volcanic origin or the result of human or animal activities. Stranded near the shore of a reservoir or watercourse is called a shoal; the shallow ocean area adjacent to the mainland is the continental shelf. Shallows can be permanently hidden under water or appear on the surface of the water periodically (for example, during low tide in the seas, changes in the water level in rivers from water content) in the form of islands, sediments, side streams, spits, etc.