<P> Typically, streams are said to have a particular profile, beginning with steep gradients, no flood plain, and little shifting of channels, eventually evolving into streams with low gradients, wide flood plains, and extensive meanders . The initial stage is sometimes termed a "young" or "immature" stream, and the later state a "mature" or "old" stream . However, a stream may meander for some distance before falling into a "young" stream condition . </P> <Dl> <Dt> Stream load </Dt> </Dl> <P> Streams can carry sediment, or alluvium . The amount of load it can carry (capacity) as well as the largest object it can carry (competence) are both dependent on the velocity of the stream . </P> <P> A perennial stream is one which flows continuously all year . Some perennial streams may only have continuous flow in segments of its stream bed year round during years of normal rainfall . </P>

Where does the water in rivers come from what causes rivers to flow