Rivers and streams can be classified according to their degree of permanence, the shape of their channels, and their branching network.

Degree of Permanence

Permanent streams and rivers flow all year long. Enough water is available to keep them from drying up completely, even during a long, dry spell. Most large rivers are permanent.

Intermittent streams and rivers are seasonal. They occur only during the rainy season or in the spring after the snow melts. Rivers and streams in desert regions tend to be intermittent, where they are also called wadis or arroyos.

Interrupted streams and rivers flow above ground in some places and then disappear from sight as they dip down under sand and gravel to flow underground in other places. The Santa Fe River in Florida is an example of an interrupted river.

Channel Shape

The material over...