Rock/Mortar leaking..

[Noonan]

Hey Guys
I'm trying to finish up a pond but I can't seem to get past this last task.

One section of my pond has a rock/mortar wall. Beyond that wall is going to be a garden and also where my UV sterilizer and pump will be. This wall is on the right side of the water fall, and there is an identical one on the left side of the waterfall.

I knew it would leak.. so I purchased that black spray foam that expands. I did the wall on the left of the water fall, as I was letting it set/expand/cure I did the right wall. I gave it some time and started to fill the pond up. The left wall is fine, no leaks what so ever. The right wall leaks. I ripped the excess foam off and resprayed. Filled it up, leaked. I did this 3-4 times and now I am really not sure what to do. Every time I fill it up water is coming in from a new area. Ill spray where that water is coming from, and it will just come out from underneath the foam.

Any tips? Maybe I should approach this differently?
Anything is appreciated.

 

[MassKoi]

Someone else may chime in but I only used the black foam to adhere rocks together. I am not sure it totally seals water out. Every place there is water in my waterfall theres is EPM liner.
A picture of what you are dealing with may help solve your problem.
Good luck.....

 

[Noonan]

Ill try to get a picture in a few hours, I'm not home right now.

I didn't install the rock work, a contractor installed the rock and liner. Its not actually apart of the water fall, there's no water flowing down it or anything.