UGH!! Waterfall Foam!

[poconojoe]

There is no way, no matter how skilled the waterfall construction, that you can achieve the same without using foam.

I have to respectfully disagree.
I never use foam or adhesives.
It's all about the base you provide. Like most projects, it's the preparation that's important.
If you create a gradual sloping concave shaped base under a liner and position all the stones stepped, pitched and curved properly, the water can only return to the pond. Even if water gets behind or between the stones, it can only return to the pond due to the shape of the base underneath. The stones need to be locked into each other for permanent stability. Think of a brick wall.
As you create the base, you make stepped shelves to support the stones.
Basically creating a waterfall that functions even before adding the stones.
You also have to realize that your first attempt at finishing the "look" of the stones may not completely please you. It may take a few rebuilds or shifting of the stones to get the flow you are looking for.

 

[Lisak1]

the water can only return to the pond.

I agree with you 100% on that part - in fact, even if you do a pretty crummy job, if the liner is basically pitched toward the pond, the water will end up back in the pond.

HOWEVER, there's a big difference between ALL the water being directed OVER the rocks and some water running over, some water running under, some water running in between. In both cases all the water ends up in the same place, but the effect will be totally different.

The first is the effect you create when you foam the areas between and behind the rocks - you force ALL of the water over the rocks. A properly foamed waterfall creates one smooth surface all the way down, with no where for water to escape behind or between the rocks.

In the latter case, the water still ends up IN the pond, but much of it happens where you can't see it as it will go behind and between the rocks to make it's way downhill. No matter how skillfully you stack your rocks, you cannot avoid the reality that you are losing waterfall volume behind the rocks.

 

[poconojoe]

I agree with you 100% on that part - in fact, even if you do a pretty crummy job, if the liner is basically pitched toward the pond, the water will end up back in the pond.

HOWEVER, there's a big difference between ALL the water being directed OVER the rocks and some water running over, some water running under, some water running in between. In both cases all the water ends up in the same place, but the effect will be totally different.

The first is the effect you create when you foam the areas between and behind the rocks - you force ALL of the water over the rocks. A properly foamed waterfall creates one smooth surface all the way down, with no where for water to escape behind or between the rocks.

In the latter case, the water still ends up IN the pond, but much of it happens where you can't see it as it will go behind and between the rocks to make it's way downhill. No matter how skillfully you stack your rocks, you cannot avoid the reality that you are losing waterfall volume behind the rocks.

I hear what you're saying. Water will find it's way and the foam will help guide it where you don't want it to go. Once all the moss grows, you most likely won't be able to tell rock from foam anyway.
In my thinking, I was more concerned about water escaping the pond.
Volume of water matters too. If you have plenty of volume you won't notice if a little gets in and around the stones. And if your stones are large and flat enough, that helps too.
Sometimes I over think things or I'm too cautious in fear of losing water. But I guess that a good thing...maybe.

 

[Lisak1]

Yup - your first concern is to keep the water in the pond. And I have seen people form a "ski hill" and try to stack rocks on it and wonder why they can't keep water in the pond - the base being constructed properly is definitely the most important part. And foam will NOT keep water in a waterfall, ever. We built our waterfall to be wide and concave for a reason - we wanted no trouble keeping all the water inside the parameters of the falls.

But to get 100% of your water volume 100% over the top of the rocks, waterfall foam is your best friend. We had spots that needed re-foaming this spring - I wish I had taken video of the before and after. It's a pretty dramatic difference.

 

[addy1]

When I want to block flow I use pl roof goop, when I want to direct flow I use waterfall foam