Pond sides

[LookoutTrout]

After I spent many hours and pounds sorting out the pool heating last year my wide has decided she wants rid of the pool and have a pond instead. I'm thankful as every year I spend more time maintaining the pool than people spend swimming in it, a pond will be far less maintenance.
Anyway I'm not trying to turn one into the other, the pond will be dug in virgin clay which is naturally waterproof. I want to make it at least 4' deep but clay isn't very stable when it's wet, the sides will quickly slump making a wide and shallow puddle. I don't really want to buy a preformed pond as they are expensive shallow puddles, I suspect a flexible lining will allow the clay to slump underneath it.

Any tips on how to help a pond keep it's shape?

[Martinspuddle]

my wide has decided she wants rid of the pool and have a pond instead.

Does your dear beloved know you say that about her?!

Anyway with a garden pond it isn't wise to rely on ground clay until you know local water table. As for the depth, your talking engineering but for what I remember your pond without solid support must be twice the width of the depth to avoid collapse.

Personally I'd always say use a good quality butyl liner.

[LookoutTrout]

I don't fancy building brick walls in it so it looks like shallow is probably the answer. Most of the soil in my garden is puddling clay, I tried digging a soakaway and all it did was overflow when it rained. I'm not going to hit a water table here, it's too steep.
Time to look at other options and think some more, maybe raised sides with a liner and the middle dug down a couple of feet will work. That way the pressure will stop water building up between the liner and the soil. This is all some time in the future as I still haven't levelled the ground off or built the retaining wall above where it's going.

[Martinspuddle]

How big is your pool? ....they do make for great Koi ponds.

[LookoutTrout]

How big is your pool? ....they do make for great Koi ponds.

The pool is above ground so would make a good liner but it's been in the sun for three years and I wouldn't trust it.
I'm leaning towards digging a big round hole and laying a round brick wall to hold the dirt up, I could do it myself as nobody would see the awful brickwork I won't need a foundation as the circle will support itself, just need to make the bottom level.
I need to decide between a wildlife pond or a fish pond, the two won't work together here as any wildlife pond will end up full of frogs and herons. A wildlife pond will be much easier but I'm not keen on that because it would attract wildlife I don't want close to my bedroom window.
If I try to use a liner when the pond is impervious I have images of water getting behind the liner and it floating up, I guess I could weigh it down with sand and slabs in the bottom but don't know if the slabs would move under the sand over time and puncture it, three concrete balls might work better. I'm probably overthinking this but can't find decent examples on the net where people have done anything similar.

[black ghost]

How big is your pool? ....they do make for great Koi ponds.

A koi pond should be at least 4 foot deep.

With clay sides the water would always be muddy. You do need a liner of some description.

[Martinspuddle]

If your pool is holding water now and is a think liner, there shouldn't be an issue. As long as you use a ground liner underneath your pool liner it will last years. I wouldn't use 'concrete balls' as you don't know what leach out of them over time. Better to use a large bag of smooth stones or cobbles from the garden centre.

If funds won't stretch to a ground liner, use old hessian backed carpet or rugs to cover the bare earth.

Unless you have something like a Koi pond with large Koi you will get frogs and other wildlife. My ex wife and I use love hearing all frog mating noises during the spring and always sleep OK.

Making a Small Wildlife Pond - Timelapse - 4K

Natural Wildlife Ponds - Designs and Creations - 4K

Getting back to the original clay idea, I've never tried it but there plenty of information on the web about 'Puddled clay ponds' but think you need to establish what type of natural clay you have first.

[LookoutTrout]

The pool is 4' deep but too wide, I'm not sure if the liner would fold nicely. @black ghost Good point about muddy, when I did a soil test in a bottle after several weeks the clay still hadn't settled out. So clay/water interface can't be allowed.
The price of a liner probably isn't a problem and I doubt it will be a large portion of the overall cost, I'd rather get the right solution but think if outside pressure is equal then a flexible liner won't work well so i might need something else.

What concerns me slightly is this project keeps getting bigger with more and more things to consider, now I'm wondering about bottom drains, filter, waterfalls, retaining walls, sealant. I built a small pond a few years ago in a different house but this is turning into a bit of a monster so i might end up having a reset and buying something like this.
https://www.layzeeliving.co.uk/collecti ... 44mm-thick

@Martinspuddle Good idea about stones rather than concrete. My main problem with wildlife ponds is not being able to stop herons without completely covering it with a net. If herons weren't a problem then I could leave one side as a gentle slope and walls to make a deep end. Fish are an essential part, I don't want to end up with a mossie farm.

[Martinspuddle]

@Martinspuddle Good idea about stones rather than concrete. My main problem with wildlife ponds is not being able to stop herons without completely covering it with a net. If herons weren't a problem then I could leave one side as a gentle slope and walls to make a deep end. Fish are an essential part, I don't want to end up with a mossie farm.

Our old neighbour where we use to live had a wildlife pond that was full of everything you could list for a wild pond ...but little Mosquito larvae, reason Three-Spined Sticklebacks (Gasterosteus aculeatus) among other things.

I don't how many they had in this pond but as he said get the balance right there's no problems.

[black ghost]

What size is the pond? If it’s big enough and the sides can be vertical I would wall them and line it, or wall them and put a thin concrete(?) floor in, then paint it.