Maybe you could make it into a raised pond?

Set it on level ground and put boards or cinder blocks around it. Then fill with dirt around the sides.

Thanks catfishsam
I might have to do that if the next try is not successful, hopefully after some sun, which is non-existant at the moment in the uk.
cheers
graham

I'm afraid I can't offer more than understanding a moral support.

I had this exact same problem. My pond has a liner instead of a preform, but I wasn't even finished digging when the rains hit. Like you, I covered it with a tarp and thought I had the tarp lifted enough on boards so that the water was roll off of it. Unfortunately, the tarp collapsed and the rain completely filled my pond. The clay soil wasn't draining, so on the next clear day, I got a bucket and bailed it out by hand and resumed digging in the mud. We've had only a few dry days here and there since, and what I ended up with because of it was a pond that is smaller and shallower than I originally intended. I had fish on order and I wanted it to be operating for at least a few days before I put them in. Two months later, it's still raining almost every day. The fish are fine, but I'm not sure the size of my pond can accommodate 7 koi after they grow up, so in the future I'm probably looking at having to rework the whole thing. We've never had this much rain before, and it really messed up the pond I've wanted most of my life!

I have something of the same phenomenon in my yard. I have low spots where water sits for days until it percs through the clay. Some double-digging helped, but didn't completely eliminate the problem.

Once the pond is full though, the water from below won't lift it up, unless you're on an artesian well or something! Just raise the edge a few inches above the ground and bank the soil up to it to encourage runoff. Good luck!

Thanks for your replies it is early evening in uk and it has been raining again, roll on tomorrow when I will be again scooping out the bottom of my PIT.
Happy Days

Banking the edges is a good idea so rain runs away from the edges of the pond. Also - did you backfill with sandy soil or sand? Fill it in with the clay only and pack it really tight.

The problem with clay soil, which I also have, is the water will not drain, but it is a bonus because it doesn't collapse and cave in like sandy soil can. I have so much clay I probably didn't need a liner but opted for continuous clarity.

I've seen people dig holes to put in trees and they backfill with top soil out of a bag. When it rains the rain runs right through the fast draining bagged top soil and then hits the clay 'bottom' of the hole and stops. Trees in clay must be planted high and the backfill must be mostly the native clay soil, mixed with some decent soil, so the water cannot fill the hole so fast.

Clay soil is actually a better base in which to build a pond if you can stop rain water from running where you don't want it to go.

Remember water seeks true level and it only takes a slight variance in grade to make it go whatever direction you want it to move. The edge of your pond must be higher than the surrounding grade - and then pack in the clay soil very tight around the outside with a gentle downward slope leading away from the pond edge into the lawn, etc. I would have it at least 3 or 4 inches above grade and you can disguise it with rocks and plants. Don't have your pond be the lowest point and don't have fast draining soil (with sand) as a backfill.

If you are planting on a slope the concept is the same with making a series of berms and swales to grade the land around your pond to make downward flowing water move away or around the pond and not make your pond the low or on-grade spot where water can seep into the hole.

Graham, wish you could send some of that rain back across the big pond! :-)

Don't give up. Once the rain slows and it drains ( i'm sending the devil a warm up suit)when you have the preform filled with water, the weight should keep it down . I have a house in Ireland and fortunately the limestone lets the water seep away.
The groundwater may need an assist to run off , such as a perforated pipe leading away from the pond on any downhill side if there is one. Similar to a drainage field in a septic system.

We saw you were gettting lots of flooding there in the UK. I hope it abates for you soon. I honestly would think about doing an above-ground pond, if your area has drainage problems. What's going to happen when your pond is established and full of plants and fish and it floods again? Then you will have a much bigger and more heartbreaking problem to deal with. Think long term.

Graham if I am reading your thread correctly you put the pond in and than covered it with a tarp to keep the rain out. So I am assuming that the pond was empty. If this is the case put the pond in fill it full of water and as long as the water in the pond is at least as high as the ground water the pond will be fine.
Mike

That's what I always thought too Mike and Donkey. The weight of the water in the pond will be heavier than the rain that washes beneath or around it.
A few heavy stones or masonry around the edges might be enough to keep it in place until it gets filled completely...

Thanks all you guys it is great to have so many people trying to help me, it is a bit disheartening to see it going awry but,i am so pleased that i posted my problem.
mike il you were right i made the first mistake first time around by not filling the pond up, but, thought 2nd time around by filling half way the weight would force it down then by infilling with soft sand it would be ready for the next step (electrics & pump) but no the rain spoilt it again.
Donkey i have been thinking of just that.I used soft sand to infill was i right? i was thinking next time to try sharp sand because of all the rain some of the edges have collapsed now!

You might have to dig out all the sand and start over, but once you get the hole right, put the pond in and fill it right up. I know from experience, the ground water will lift an empty pond all the way up, a half full pond half way up, and a full pond not a lick!

Thanks Gemini jim I have decided to dig out the sand and dig down (hopefully not all the way to you guys in the states but,) a few more feet and then put in some perforated piping and some peashingle to bed it down then, infill with sharp sand, fit pond and like you said fill pond to nearly the top.
Fingers crossed!
Hopefully we in the uk are due for some warmer weather so I can get it done a.s.a.p. as my back garden looks a right mess!
Good luck with all your gardens & ponds

Hi --

I don't understand why you're putting sand in there. I only have a small pond but I simply dug a hole, put it a liner, and filled it with water. I was thinking --- why not put some rocks in the bottom (large ones) to weight it down? At least until it's filled?

hope your next go-round works!

few more feet and then put in some perforated piping and some peashingle to bed it down then
====================
Realize that this pipe needs to lead some where. You'll have to dig a fairly long trench where you lead it to drain.
No idea why you even need this because when you put your pond in and backfill around it no water will get underneath it anyway. Drain pipe like this is usually put near basements, cellars to stop it from creating hydrostatic pressure or flooding.

Also, if you're getting this much rain, and have such a small pond, consider putting in an overflow drain. Some sort of slot with a hose on it so the water can just gracefully exit the pond when the rain is heavy.
If not, it will just overflow over the entire thing and you if you have fish you'll have them flopping in the yard.
Remember to screen this overflow pipe or tube so the fish can't get out that way.

As i have said previously i backfilled with sand which washed away but, because we have clay soil it the rain seems to find its way to the hole and filling with water, yet again it has rained and i have been out there scooping the water out of the hole and have now dug down another 15" (1 1/2ft) in between showers and think i have now hit the original soakaway, the garden looks a right mess, but it has to look worse to get better.
I just keep praying for a few bright sunny days to get on with it.
Thanks for your posts.