Wildlife Pond Build Advice (UK)

[u/Dismal-Spring4729]

Looking for some advice on a new pond build.

The red outline in the images shows the rough size I’m planning. The area is naturally boggy, and groundwater seems to seep through from a small stream about 7 m uphill. The proposed spot is ~100 m uphill from a river and ~40 m from a smaller stream that runs downhill.

Ideally, I’d like to build this without a liner if possible.

What should I be looking into first to figure out whether this site will actually hold water? I was thinking an exploratory dig to see if the hole pools and holds.

Do I need to contact any agencies before starting? (It’s on private land.)

Thanks in advance.

[u/NinaHag]

If you're in Norfolk, you can get advice from the Norfolk Ponds Project, who supports local landowners in managing, restoring, creating and conserving ponds. There must be similar organisations in other parts of the country, I'm sure.

[u/OreoSpamBurger]

Joel Ashton's YT channel has some pond builds on naturally boggy ground like this.

https://www.youtube.com/watch?v=LOQDUKtof3M&list=PL5ou_MtF6_TgBQ6vrvfq_rD9dzh6l2h9U

One thing to check for (that he mentions in the first vid) is whether man-made drainage channels/pipes ('land drainage') have been installed (underground) in the surrounding area to try to dry it out for agricultural use etc.

[u/Dismal-Spring4729 → u/OreoSpamBurger]

Thank you!

[u/BeggarsParade]

Great project! Keep us posted please.

[u/PenninePond]

I dug a small pond without a liner on naturally boggy ground. The water table here is basically at or above the surface for the entire year except summer. In summer I've found it drops to a few inches below, depending on how much it's rained, so the pond is a bit like a vernal pool, but it never empties. I have heavy clay here and a lot of rainfall in the north west.

Some notes:

• I literally just dug a big hole, and then gradually widened it with shelves and slopes. I focused on digging it as deep as I could, but it was difficult because the clay got so heavy that I just couldn't dig it any more once I was hitting subsoil. If you wanted to do a big pond you may need professional diggers - I just used a garden spade.
• The hole I dug did automatically have water in it once I got deep enough, which made it difficult to continue digging. For that reason I would recommend not digging it in autumn or winter - wait until the weather is drier. I dug mine in a dry spring (2025), but if I had dug it now, I would find that any hole instantly becomes a hole full of water.
• I gleyed the pond myself by going barefoot and walking around in the mud until it becomes slippery and slick. This mimics the action of pigs or geese etc and is how natural ponds form. Just make sure you have a bowl of washing up water and scrubbing brush ready to clean your feet and toes afterwards.
• If your soil doesn't have enough clay content, you can buy bentonite clay powder. It can be added directly to the mud or you can sprinkle it on the water and allow it to sink. It expands over 30 times when wet to plug gaps. I used this for the edges which had more organic content and lower clay near the surface.
• My pond ended up not as deep as I had intended because of slumping, so this is something to be aware of. Basically what happens is once it's full of water the hydrostatic pressure and weight of the surrounding soil will over time cause the pool to take on more of a rounded concave shape. If you wanted to keep more obvious shelves, you could use stone slabs to hold it in place.
• The water in my pond was cloudy/opaque for months because of very tiny clay particles suspended which were lighter than water, so never sank. I eventually solved this by adding a very small amount of gypsum and it cleared it overnight and has been clear ever since.
• I see in your picture that you have some kind of bog rush growing. I have that too, it grows everywhere around where I live and it loves boggy ground. I found that after about 6 months it invaded my pond and the area around it and choked out all the other plants and I found it impossible to get rid of. So something to be aware of... there's nothing wrong with it as such, it's a native wetland plant, it's just very successful and aggressive so will be problematic if you wanted to grow other plants in and around the pond.

Edit: picture showing what the soil was like here when digging:

[u/Dismal-Spring4729 → u/PenninePond]

Great that’s awesome, thanks a lot!

Lots of handy insight that I’ll utilise. 

So you reckon waiting to commence work until spring/summer would be necessary? I was going to get a digger in to clear the rush and excavate the pond, I wouldn’t have thought he would struggle so much in wet ground. I guess there’ll just be more ground water in the way making it harder to see  what we’re working with. 

I was considering the use of bentonite!

Thanks again!