Vertical walls?

[old-muel]

So im looking at doing a small diy rec/swim pond. We're talking dug inground, underlay, epdm rubber liner, etc. All my previous ponds have been successful using this method & doing shelves that step up in height as it goes out from the deepest part in the centre & then rocking in plus pebbles, plants etc. My current challenge is i definitely don't have space for the concentric shelves all the way around & will need to have at least one (probly more) vertical wall (depth will be 1400-1500mm (4-5ft). I'm thinking deep plunge pool type thing with part natural rock & part formal vertical walls of some type. Now I've seen that team aquascape use what they call "engineered brick" to do the vertical walls & i think I've seen david pagan-butler maybe do in-pond verticall retaining walls from hardwood sleepers? (not real keen on wood for this application lol). Not wanting to spend a fortune on getting this done also, will spend what's necessary but surely there's some out of the box diy-friendly & cheap material i can find, those "engineered bricks" look expensive.
Now what are the technical material-science type requirements here? What else have people used? I'll need pristine water quality/stability for fish & myself so basically whatever i use should be fairly inert yeah? Would cinder blocks leach anything or alter ph/other parameters? What about clay pavers? I wonder if small pieces of slate are expensive, I've also seen the aquascape guys use those stacked as walls
Any tidbits for me here guys?
Hi & thanks in advance!
Edit: I'm actually not sure if this wall(s) will need to structurally hold the dirt back or not, kinda been thinking the water pressure alone would hold vertical walls steady, of this height in clay soil, & that I'm just looking to hide & protect the liner, but will it need to be structural as well? What factors does this depend upon? Any resources on this topic?

 

[addy1]

Welcome to the forum!

My ponds has straight walls, 5 foot plus. I used nothing to hold the dirt back. Just liner and water.

I did not rock my pond.

 

[old-muel]

Hi Addy thanks. That's awesome to know, yeah I think I'm confident just having liner & water structurally holding back the soil, but having any liner showing at the end is a big no-no for me, mainly coz the liner needs protecting from puncture, I hate the though of the thousand-odd dollar liner just sitting there waiting for a fallen branch or some ducks claws, people's sharp jewellery or absolutely anything at all to put a hole in it, plus the look of bare liner doesn't do much for me either, so I think plan sofar is I'll probably have some shelves on the far side (viewable from house) that are rocked in, I'll make them as tall & narrow as possible, like 3x50cm high shelves that are only like 20cm width, & do the house-adjacent side that you walk up to as a vertical wall, with a constructed wall of clay pavers inside the liner (to hide & protect liner). Clay pavers are readily available for free. Anyone got any reason not to use clay pavers? (Not aesthetic reasons). Are they inert as far as leaching etc over time does anyone know??
Edit: just read that engineered brick is made for civil projects to withstand damp environments, will my free clay pavers break down over time submerged??
Do I need the engineered brick?
What else could I line inside a vertical wall with?

 

[j.w]

@old-muel
I used rock on my shelf and then more rock around edge.
Maybe rock on a roll would work? I've never used it but some here have.

 

[GBBUDD]

By clay papers i believe your just talking larger bricks as they too are made of mud clay straw and fired.

If they are fired I'd doubt there's anything left to fall appart.

Concrete papers will last as long as the liner will. And im with you on exposed liner for a swim pond. Retaining wall blocks or cinderblocks are concrete around here they will not degrade, unless they are poorly made. Most will outlive the liner.
Unfortunately as someone has 4 foot drops in their pond it's their soil type that allows this. Yes head pressure pushing back on the wall can help tremendously but it's all in your soils. If you have sugar sand , no question I'd go with some form of a retaining wall.
As far as leaving new concrete can have a ph of 14 now that's no good for fish. But it does not take long for this so leach and when it does it actualy helps to buffer the water. After soaking the concrete for a week just drain out the pond and your off. If you test the water and the ph is fine I'd still do a 25 % waterchange before adding fish.
Myself I'd dig a trench where I wanted my retaining wall place hd fabric gravel and then build my wall on that. I too have a straight wall but I wanted boulders so I built a cinderblock wall outside the liner. And then rocked inside the liner. Over kill yes but that's how I build "it's not going anywhere ! " I have a section of this in my showcase. The link is below.

 

[GBBUDD]

View attachment 168620
View attachment 168621 @old-muel
I used rock on my shelf and then more rock around edge.
Maybe rock on a roll would work? I've never used it but some here have.

View attachment 168622

Might as well build with cinderblock . I'm not a huge fan of rock on a roll. It works it's better than seeing liner but the simple technique of a step around the pond and no liner hidding is neccessary

 

[addy1]

Here is a good thread about making a pond edge.

Let's talk Edging a Liner pond.

It was a nice evening, so I decided to record a video while walking around the pond. Talking about techniques I used to hide the liner above the water line. The pond is 6 years old now and has certainly matured. I am going to put together a post similar to my showcase but solely talking about...

www.gardenpondforum.com

 

[GBBUDD]

Here is a good thread about making a pond edge.

Let's talk Edging a Liner pond.

It was a nice evening, so I decided to record a video while walking around the pond. Talking about techniques I used to hide the liner above the water line. The pond is 6 years old now and has certainly matured. I am going to put together a post similar to my showcase but solely talking about...

www.gardenpondforum.com

In most of my pond i did not follow the standard shelf around the edge of the pond. In several areas I left the shelf at grade like many do but they realy aren't so sure how to hide the liner now.
My go to is not rock on a roll as to me that is more of a we don't know how to hide the liner this will work,and it does.
But to me I'd rather use leftover fabric" underlayment" giving nature a place to grow. All rock all the way around the pond looks man made . Which can be fine but in my book nature is the artist.
Ok I see my video got posted so I'll stop here if you have any questions feel free to ask