Giant Boulder and pond liner attachment

[Jim Leiterman]

This is a very large boulder of quartz/composite granite? Can easily cut water paths using a Dremel and a grinding wheel. Original owner of the house cut a channel to dump water to the side in that little niche on the right but I tend to do things large. Distributing water across the top on this side of the boulder (You're only seeing this side of it) I can channel water all over the surface including the area zig zagging in the front and force it right. Can add a couple falls with additional large rocks on the left, and flowing behind that big rock in the foreground (creating a natural wall) and into a buried aqua basin with a pump and water rocks for cover. I've pulled back some of the ground cover seeing if there was room to bury the basin. My problem is how do I attach a liner to the edge of that boulder so water doesn't get behind the liner and thus a leak. I can easily hide the liner keeping it above the flow from the left side and low enough covered by small rocks for camouflage. The front and right would be through natural gravity flow placement and rock placement at the edge. This is in the mountains around 2000 feet so gets hot in the Summer and Cold in the Winter.

 

[Lisak1]

We've had questions like this before. Without lifting the rock, I just don't see a way to completely seal it so it won't allow water to leak around a liner. The rock isn't perfectly flat so that's one strike against you. If it were, you may be able to create a tight seal. Even then it would be very, very dicey at best. Is there an existing basin? Or are you thinking of adding one?

 

[Jim Leiterman]

Adding a basin. There's room for a large one if the amount of streaming water requires larger to keep the pump with plenty of reserves to pump. I thought of cutting an upward grove into the rock face but that could be problematic.

 

[combatwombat]

Don’t know how well it would work, but if it’s easy to dremel/chisel the rock line you mentioned, you might cut a deep reveal horizontally across the face of the rock and silicone the liner into the reveal.

 

[GBBUDD]

If that is a mix of granite and quartz and you can Easily cut into it with a dtemel / a toy in the rock cutting world. Then i would suspect you msy have weathered granite on the surface. I can see all sorts of fractures cracks. And thats less then ideal. Trying to contain the water could be impossible. But by using my choice would be butle caulking, or epoxy, and water fall foam you could fight with it. There is nothing more difficult then what you thinking. But if it was i and my back yard id probaby give it a shot.
But using a demel is hardly the tools i would start with. But trust me you have all the hours youll want trying to connect cuts where the dremel wil be invaluable. But i would be starting with a construction demo saw with a 16 " masonry diamond blade. And like cw said cut a channel in the rock. Heres where it gets ugly a clean cut isnt wide enough for the rubber caulking or epoxy and sliping the ruber in the cut wdging it in the cut and securing it. Youll find you need to widen at least the outside edge of the cut.
A grinder with a masonry cut off wheel as well as a cup wheel scarifier will be needed as will probably a demo hammer. Oh and lots of time money and patienve. It can be done but it is one of those builds i would discourage 75 percent of those thinking of tAckling such a task. A second cut above the first to act as a flasing of rubber to limot the amount of water that makes it to the main seal may be required as well. And thats for the reasons you mentioned. Hot and cold freeze and thaw your rock will constantly change

 

[Mmathis]

Now, that’s a nice rock!

 

[j.w]

@Jim Leiterman Love that rock!