I did the Hickory Valley log pond way back in about 1976 with clear casting paper weight resin, worked great. So I thought I knew what I was doing when I went to attack the Hickory Bridge T-trak module.
I did the entire thing with Michaels castin' craft resin, which is some of the stinkiest stuff imaginable as well as exothermic; the pour was 1/4 x 10 x 34 inches so that's a LOT of material.
What a disaster that was. First, it started to ripple... then it broke loose from the bottom and look 'silvered', well... I can live with that...then it shrank and split right at the bridge piers. I panicked and ripped the stuff out before it got worse as it was still warm and a little soft, in the process, ruined the carefully painted plaster bottom. Took several weeks to repair all the damage and redo it for another shot.
This time I used Deep Pour.... about 2 1/2 bottles worth to do the same depth, and that was now over two years ago. It worked GREAT. It hasn't warped, cracked or yellowed. A lot of people have now seen this at Altoona. So it's a hearty endorsement to say the least. Since then I used it on the creek on the Trunkeyville module, and I'll be using it again. It did what it was supposed to do and didn't stink up the place either.
The creek at Trunkeyville had the water effects ripples added:
I've got another log pond to do, and a creek, and I'll be using it again. I never want to risk total failure of a final scenic detail like I did on the bridge again. If that had hardened after it cracked I think I would have thrown the entire module out.