The main difference between stream pools and ponds is that stream pools

Ponds and lakes are inland bodies of water that can be either natural or manmade. Lakes are typically larger than ponds and are fed by rivers. Stream pools are a part of a river or creek where the movement of water is slower and there is a greater water depth.

It depends on the surface of the levels. the rougher the surface, the greater is the frictional force. for rougher surfaces, you would need to exert greater force to move the object. the concept is that, you must overcome the frictional force in order to bring the object into motion. this is the reason why we add lubricants to the joints so they could easily move. this answer was on