So - I'm about to dive into the deep end of the pool.
In Charlie Fox I am going to submerge a jeep. Its going to be such that you'll be able to see under the water. That's going to call for about 2" of water. I am using poured casting resin for my water.
I've poured water 1/2-3/4 of an inch with no problems.

Does anyone have any tips on deep water?

Scott, do the same thing you did with your M3 river crossing dio but add another layer or two. I would probably start with a thin layer and color it bluish or greenish to give it that deep water look. Let it dry (harden) and then add another layer and also color it but this time less than the first layer. Let that dry (harden) and finally the last layer would be just clear resin. I think that would give you a nice illusion of depth.

Marty hit the nail on the head! Layers with the color between them will give the illusion of depth.

Good point Marty - I was basically going to try the layer deal - didn't know what the ramifications would be going that deep. You just hit on one thing that I need to experiment with - color!
I was going to tint the actual resin with resin dye. Since you'll be able to see the water in cut away view I'll have to be more careful about color demarcation.
Interesting challenge - glad you mentioned color. Thanks

Either of you two guys use resin dye??

Scott, if you worry about color demarcation then you may need to apply several thin layers instead of two or three thick ones. That way you will probably be able to achieve effect of gradual color change.

Sounds like a plan. This item is the one item on this whole diorama that I can't "Undo". I can repaint the ground, I can replant the foliage, I can resculpt the figures.
I can't repour the resin. Once its down Its down.

You could always test it first. Try pouring it into a clear plastic cup and see how the layers come out.

Bingo - I owe you a beer Marty!!!! (or whatever it is you drink).

Plastic cup - of course!!!!

Hey Scott, I will have an Amstel

Bartender - Give that man an Amstel!

Speaking of Amstel - anyone catch the Amstel Gold bicycle race in the Netherlands? Pretty cool stuff.