Need help with waterfall - How do I seal pond liner so it doesn't leak?

[beforeamountain]

Pond had been sitting for a decade when I bought the house so I added pond liner and sealed the area under the waterfall with Loctite PL Roof caulk. I also tried 100% silicone which worked a bit better, but after a couple months of running it tore free. Based on this design, I'm not sure how to add pond liner and/or seal the area under the waterfall so it doesn't leak through.
I'm open to starting over with new liner as well, as the grey is not an ideal color.

 

[Hound Heaven]

I used that same product recently to join my bog and pond liners together. Also used it on my previous liner successfully. I didn't have water dropping onto it, just flowing over it fwiw. Good luck, I'm sure others with more experience will speak up.

 

[addy1]

It's as all I use, works great.

Needs to be dry and clean.

 

[j.w]

@beforeamountain

 

[jgrandmont]

Seems to me that you might want to dismantle the last "step" of the waterfall where it meets the pond and put a piece of liner UNDER the waterfall liner (assuming there is one; kind of hard to see from the pics) and OVER the pond liner. There should be quite a bit of overlap. Not sure about what adhesive(s) to use but I'm sure others here will have recommendations.

 

[GBBUDD]

Seaming is not hard but it is demanding . As it must be clean and dry. The glue has to be good and has never frozen. And when you do your seam try it on some scrap first get familiar with it. You can also seam over the seam something i do do . As glues can fail so before i put to s of rock and boulders on a seam im going to seam over the seam the is over the first seam. . The liner its self shoulf fail long before my seam does. I SHOULD ADD THE GLUE IS A CONTACT CEMENT. MEANING BOTHE SURFACES GET A COATING AND BOTH COATS NEED TO DRY TO WHERE WHEN YOU TOUCH IT WITH YOUR FINGER IT IS DRY. YES DRY THEM WHEN YOU PUT THE TWO PIECES TOGETHER ONCE THEY TOUCH EACH OTHER THERE IS NO GOING BACK . . THE SHOULD CALL IT FIRST CONTACT CEMENT Seaming EPDM liner | Garden Pond Forums https://share.google/IghbzrMF1k9HK75rM

 

[beforeamountain]

Seems to me that you might want to dismantle the last "step" of the waterfall where it meets the pond and put a piece of liner UNDER the waterfall liner (assuming there is one; kind of hard to see from the pics) and OVER the pond liner. There should be quite a bit of overlap. Not sure about what adhesive(s) to use but I'm sure others here will have recommendations.

This is what I see other ponds doing with waterfalls, but I cannot dismantle this one as it is all concrete.

I might try again next season to seal it again, but water does flow directly over it so I feel it will only last so long.

Any other ideas? Thank you for your responses so far!

 

[Lisak1]

It looks like your waterfall is a solid piece. I don't know that you will ever be happy with a seam at that point where the waterfall structure meets the pond edge.

I would consider lining your whole waterfall and then overlapping the waterfall liner over the pond liner a good distance down into the pond. It's the only way to assure a leak free situation.