Introduction to Virtual River -- Page 2 of 25

	Streams can gain much of their flow from groundwater springs. Here is a picture of a spring in Idaho which produces a moderate size creek -- Toms Creek -- that flows off to the right.

	Rivers also get their water during storms. This is especially true when the underlying soil is saturated and the rain can no longer seep into the ground. This picture of a hillside in California shows that the soil has become saturated with water ponding at the surface. Notice that some channels are starting to form and the standing water is beginning to move downhill.