When a river flows down a steep slope, the gravitational force that pulls the water downward is stronger than it would be on water flowing down a gentle slope, resulting in the river having a greater level of velocity.

How does slope affect water flow?

Length of slope – as water moves down a slope it picks up speed. The longer the slope is, the greater the speed and energy available to cause erosion.

What does stream velocity depend on?

A stream’s velocity depends on position in the stream channel, irregularities in the stream channel caused by resistant rock, and stream gradient. Friction slows water along channel edges. Friction is greater in wider, shallower streams and less in narrower, deeper streams.