Catherine, I'm working on the floating liner issue, too but it doesn't seem to me that there are a lot of options.
On mine, the rocks are actually stacked on a plywood platform so the liner wraps around the platform and tucks back between the platform and the rim of the tank. I need o be able to take mine apart in the winter but I have been wondering if silicone might bond the liner to the tank for a season. I haven't bothered to try as this is working fine. I'm planning on more plants to diguise the liner "ruffle".

See the illustration below (which also answers the question of why I haven't made it as an artist LOL!)
{{gwi:194841}}

I'll let someone else speak as to an alternative for liner but the stuff is really strong and you'll be putting rocks on it, I imagine. I'd worry that something else would fail.

Vanessa

Do yourself a favor and use real EPDM fish-safe pond liner (NOT plastic sheeting, NOT roofing liner).

As far as "floating" is concerned... how is your pond constructed? Liner? Preform? Concrete? The falls liner should definitely extend below the pond water's surface and should be adhered to the pond's inner wall to not only avoid it floating, but to also prevent a wicking effect (where water is actually drawn up the underside of the liner and out of the pond).

If pond has a rubber liner or plastic tub, I would use seaming tape to secure the liner to pond's inner wall (this is a strong single-sided tape made of the same material pond liner is made of).

Thanks Vanessa,
I actually had forgotten about the weight and roughness of the rocks on the plastic. Maybe I'll stick with liner. Its too bad I had to buy so much though. Fortunately, it was on sale.
I wonder how wide it needs to be........like water could just run off the sides of the liner too, right? I guess its probably supposed to all be sloped down just a little, so things go down, instead of sideways? I'm not very good at envisioning things in my head.........I have to SEE them to figure things out!
Hubby and I are going out tomorrow to look for rock, to finally put around my stocktanks. Too bad its all so heavy! I have 2 stocktanks in the ground next to each other, and I'm afraid I won't like the looks once I get it done. It might just be too much rock. So I'm thinking of buying enough for 1 tank first. I'll pick rock that is fairly common so I can buy more of it later.
For several years, I've been looking for the kind of rock I have around my little preform. I think its Pennsylvania bluestone. I'm almost glad I couldn't find any, because now I want a rough stone that moss will hold on to.
I'll probably want something different next year! That's what scares me about buying all this heavy rock.
We have a chimney that we are eventually going to get rid of, and it has the rock I want in it. I asked hubby if we could start hammering out the rocks now.....but he said no. haha
What is going to support all that rock on your plywood?
I'm going to have to add more soil around the lip of the stocktank, so that all that rock isn't resting on the stocktank. DH wants a double layer of rock, but that's just too much rock around my little tank. I just hate dealing with heavy stuff. If we bring it home in my van, I hope my van doesn't break in half. ;)
We've had an extra field stone stepping stone for a long time. Its about 24"x15" and I thought it would make a great ledge for the waterfall. I couldn't even begin to pick it up, even a tiny bit. Rocks are heavy!
When are you going to build your's?
I sure hope the frogs don't get upset with me raising the sides with rock.

Thanks njpondpro. We must have been writing at the same time.
I'm using it on a 300 gallon Rubbermaid stocktank. Would that tape work on that?
How do I keep it from leaking out the sides of the waterfall? Do I use that tape on the rocks on the sides too?

P.S. I just realized that the liner I got is a "PVC" liner. Is that okay? Its going to be a VERY small waterfall.

The problem with PVC is that it is very prone to damage from UV radiation (sunlight). It will eventually become extremely brittle and prone to cracking. I have not worked much with PVC liners so you should read the manufactures instructions carefully - they usually specify that no part of the liner should ever be exposed to the light (meaning it all has to be covered with dirt, rocks, gravel, etc).

When the liner is placed in your water fall or stream, it needs to be shaped like a "U" in order to prevent water from running out the sides (really a "U" with a very wide, flat bottom and short vertical sides). This may be accomplished by sandwiching the vertical sides of the liner between 2 rocks (one in the stream/falls, and one outside) or between a rock inside the stream/falls and the dirt outside it.

Be sure that whatever material you are using to construct you falls out of (soil?) is packed very solid - once it starts to shift or settle the liner will settle also and you'll get some leaks there.

Thanks njpondpro,
By "U", do you mean that you take a flat piece of liner, and make sure that the sides are raised? LOL! I have trouble visualizing some things. I probably won't truly understand it until I'm out there in the dirt, putting it together........so I may be back sometime with more questions.
Thanks for your help!

Vanessa.........I just looked at your drawing (and quite a nice drawing I might add!) again, and it helps with a question I was having. Rather than gluing the liner to the inside of the stocktank, I could just fold it back, catch it under the rock, and then just have a little bit come down in the water. It probably won't show if it floats, and the pressure of the stone on the fold will keep it from leaking, right? Or could it still leak laterally from there if it wicks?
Man, I'm having trouble picturing this stuff in my head. I guess I just need to get out there and play around with it.

"By "U", do you mean that you take a flat piece of liner, and make sure that the sides are raised?"

Yes! If you simply lay the liner flat, what's too keep the water running off the sides?

Thanks njpondpro.

Hi Catherine,
My arrangement doesn't leak (I keep checking) as the water pours off the front edge and, even if it dribbles backwards and undermeath, the liner is there PLUS it's "U" shaped. I have some scrap 2X4 under the liner on each side with rocks piled over it to hide it and channel the water forward. Yours will be on the ground so njpondpro's suggestion of packed earth or rocks would be better. BTW: the plywood is scrap subfloor so it's pretty sturdy. The front edge is supported by the tank - galvanized - and the back corners have pvc pipe legs that are filled with plaster and are bolted to the plywood. It's going nowhere!

Funny, I have no problem visualizing things. Like, for instance, I can visualize you surreptitiously chipping away at your fireplace to get the good stone out!

Vanessa

LOL Vanessa.........I was just standing outside today, looking at the chimney stone, thinking how perfect it would have been! And it would have been so meaningful to use it on the pond, instead of "imported" rocks. oh well. Maybe by the time it comes down, we'll have a bigger pond to put it around!
One question for you........are you sure its okay to put all that weight on the rim of your stocktank? I'm going to support all the stone around mine on other rocks, so it barely rests on the lip. I can't remember for sure, but I'm thinking someone brought up the issue of not putting too much weight on the lips of the stocktanks. Maybe it would be good to put 2 more PVC pipes right behind the stocktank, under the plywood shelf??
Back to my questions: Should I build up the soil where I'm going to put the waterfall, and put the liner over that........and then start adding the rocks? Do I pull up the sides of the liner, and and lay them over rocks, to make that "U"? Or could I sculpt the soil in a horseshoe-type shape, and lay the liner over that? Would that raise the sides enough to prevent leaks?

hahaha I guess I need to go out there and start figuring it out. I have major problems leaning over and I guess I'm not looking forward to it, and want to have a real viable plan before I even start it.
The last thing I want is to have it all done, and really like it, then look out at the end of the day and have the pond empty. hahaha So I want to make it perfect to start with.
So is your built-up waterfall done already? I want pics!!

Catherine,
I had more trouble with my waterfall then any other part of my pond. It took several years to make all the problems go away. I learned two things. Moving water has a tendency to go the way it wants to rather then the way you want it to go. Also, a small amount of water not reentering your pond will empty it relatively quickly.

My final solution was to place a plastic sled, the kind children use in snow, to contain the water flow from my biofilter tank to the pond. I was able to find a black sled and camouflaged it with flat rock. I know it sounds strange, but I have not had a problem with leakage since installing it.

This is not the real solution but,(and I'm sure more experienced ponders can tell you the right way) my hubby plugged as many leaks as we could find and then I have planted water loving plants in the areas that spill-over, or splashing happens. What amount of water we lose goes to help the side plants, and I fill the pond as it goes down. For us it only amounts to about an inch of water loss in a week or two. Our pond is not quite a full year old. We have learned from this site to try what we read and then make adjustments given our space. We were lucky that the falls hubby built began as a natural hill that was well above the area for the pond. it was too steep to plan a flower bed and just evolved into the falls for the pond.

Thanks john and naturelover.