what are the streams that contribute to a river system called
Every river is part of a larger system-a watershed, which is the land drained by a river and its tributaries. Rivers are large natural streams of water flowing in channels and emptying into larger bodies of water. This diagram shows some common characteristics of a river system.he. river mouth. is the place where a river flows into a larger body of water, such as another river, a lake, or an ocean. Upstream. is in the direction of or nearer to the source of a river.