Current+&+Velocity5

Current and Velocity
= Currents = Currents is streams and rivers only flow one direction, downstream. The current carries substances, for example nutrients, over organisms in the water. The organisms must use the substances immediately or else the substance will continue downstream and the organism will have to wait for the current to bring more.

= Velocity =

Velocity changes when a stream changes direction or changes depth. When there's a decrease in slope, the velocity also reduces. However with the widening of a river and the smoothing of the river's bed, the velocity increases.

( the bed of a river is smooth, the velocity increases) (the bed of a rough river, friction increases, therefore less velocity)

= Affecting Wildlife = With currents, organisms are affected by the currents creating force, making it hard to stay in one place. With velocity, it doesn't really affect species. Most species can live with any velocity in a stream or river.

(Currents: a mollusk can resist the force of a current)

(most species can live in this river due to its velocity)

= Humans Impact =

Humans can affect velocity by digging out a river or widening it.

(a machine removing soil from a river)