DrDave said:That would make it 16 gauge steel.
Hi DrDave.....glad about your interest.
I noticed that your in to different things just like me.
I am more of a designer but the result of my pond was all an after thought. it was suppose to be a stream from one end to another. it was only after I got the flagstone material when I got the idea to have a horizontal falls. had to think about water distribution, the idea of having a upper resevoir came along. it had to be custom made.
also when I design and had it made of galv steel the after thought of hiding it was amazingly simple. basically put blocks on the leveled resvervoir using it as feet for the big flagstone tops (cover) water looks liike it comming out from a slot on the rock.
You could probably market/produce resvervoirs with your resources..
..just an idea 4 U:ideacyclops: