Trying to pay back some of what I am getting. Considering doing some on moving water cause I have been surfing waves in my kayak and seen the fish sitting behind the rock causing the wave.

Regarding the rebound effect. Watch the bow of your boat; there is a bow wave coming off either side. There is a similar force pushing water down around the bottom of the boat. If the watter is too shallow then the boat will slow down. Try paddling in deep watter that you know goes onto a shelf that is a foot deep; the boat will feel slower, like you are climbing something. There are some good sea Kayaking books on route finding that will go into more detail, but, being in a boat and feeling it slow down is very convincing. I am told that some of hull design is to make the energy lost when the water is parted be restored to the hull when it comes back to gether.