Johnny,
I don't mind sharing at all. I use a product called KraftKote. It is
made by Klockit. It is a two part polymer that was recomended
by my LHS. The stuff works great and has a fairly slow set-up time,
so adding details is not a problem. It hardens in 24 hours and is fully
cured in 72 hours.
I will eventually add some rapids and such using Water Effects by
Woodland Scenics.
As far as the river bottom and the pond, I just used Earth Colors from
WS. I kind of played it by ear until I got the effect I needed. Just
remember, the deeper the water the darker. Then feather in the lighter
colors as you work toward the more shallow water. Good luck, Dave