How's your waterfall and stream coming? I just built a waterfall last night, using lace rock and quick setting hydraulic cement. This project was inspired by David Taylor, you can see pictures of his waterfall at:
Tinc Vivarium #2
I did take some photos of my waterfall, though it's not yet up and running. Those pics are on my home computer, I'll post them when I get home in a couple hours. I must say that David's waterfall is amazing, and I can only hope that mine comes close. That said, I'm very happy with how it's looking so far.