What is a River System?

A river system consists of a branched network of stream channels and the adjacent slopes that contribute runoff to these channels. The sources of a river include uplands or lakes where surface runoff flows out along a defined channel. Between the channels on the ridges are drainage divides that mark the boundary between slopes that contribute water to different streams. The entire watershed is the land surface within a drainage basin that sheds water by overland flow (Figure 1).