Coping Stones & Edging

[CMP]

Hello from Qualicum Beach, British Columbia, Vancouver Island, Canada!!

Decided 2 weeks ago to fulfill a longtime dream and build myself a fish pond. 3 ft deep, 11 ft long, 5.5 ft wide. The hole will be finished today or tomorrow so it's time to start thinking about coping stones and edging!!

My friend gave me some concrete flag stones that I was planning to use as coping stones, which some pretty pink slate rock as the edging. I would like it to be (mostly) level with the existing ground.

Most of what I've found online says to carve out an L shape around the edge, and put the coping stones on top of the liner. However I also came across one site that shows the coping stones under the liner.

I'm concerned about chemicals leeching from the concrete flag stones into the pond. Is this an issue?

 

[GBBUDD]

From any concrete pavers I know of today there is no issue of leaching . BUT run off from heavy rains sure is a concern you want to have your coping or a berm of some sort diverting the storm water run off away from your pond. and generally you build your wall run the liner up the wall over the top and then place a cap to hide and hold the liner

 

[MitchM]

Welcome!
I used to live on the Island, near Butchart Gardens.
Beautiful place.
I'm not a fan of concrete stones around a pond because the freeze/thaw cycle will degrade the stones and pieces will fall into the pond. Like @GBBUDD says, make sure you have a berm that will prevent surface runoff from entering the pond.

 

[CMP]

My pond is in the high spot of the yard, and the land naturally slopes down away from the pond. I lucked out there, just started digging first then googling later, lol But I know there will be heavy traffic around the pond and the ground isn't that stable, so I def need some support before I lay the the top stones in place. I will put the liner over the blocks so that no concrete falls in, thanks for the suggestion MitchM.

Can I ask another question, the guy at the pet shop said I don't need underlay, can use old blankets etc., your thoughts? There are substantial tree roots from old growth fir and cedar trees close by.

 

[j.w]

@CMP I used old blankets, carpets w/o tacks in them,towels and anything soft. Just overlay-ed them all and all is well. I didn't have tree roots or many rocks in the soil either. Just did the underlay to be safe. Where the roots are I would put extra liner, Make it real hard for those roots to snag into your liner. Carpet works great but like I said make sure no carpet tacks in them. Some carpet companies might give you old scraps? Or maybe neighbors.