Water table and pond problem

ShepherdsBarn

We reinstated a pond last spring ... it had been made many years ago, before we bought the property. Since the recent rainy weather the pond has 'flooded from underground'!! See photos. The water has pushed the pond liner to the surface? Has anyone ever experienced this and any thoughts on how to solve the problem please? We are 149 metres (489 feet) above sea level - so not even in a valley.

K67

Is it possible there is a leak in the liner?

ShepherdsBarn

No ... the liner has been pushed up from underneath. It seems like there is a natural spring in that area, as there is a constant flow of water making its way down the garden. Before we reinstated the pond, it would often fill up when we had heavy rain. 

robairdmacraignil

If you have ground nearby that is higher up than your pond then there could be a spring under the pond depending on how the ground is sloped and what layers are permeable. There is a field close to where I live that has water springing up to the surface half way down the hill during wet weather and we are far away from sea level so you don't need to be at the bottom of a valley or close to sea level to get a spring. Is there a chance the pond was originally built to be filled by this spring? Only way I can think how to fix it would be to install a drain running from near the pond to lower ground somewhere else so the water table is lowered and it no longer reaches the surface under your pond liner.

Buttercupdays

You say you re-instated the pond - did you remove any old liner?

I'm asking because we also live up in the hills and there were ponds here made by previous owners, but ours were puddled clay, no liner.

The same thing would happen here if liner was used, as not only is all our water supplied by a spring, but new little ones constantly pop up at different places on our land following heavy rainfall. Our ponds have a more constant supply and there are some reliable enough to be channeled, but the others make maintaining land drainage difficult at times. As they move around so much, it is pointless expending time & energy digging drains, when they may re-appear next time from somewhere else!

We know we have a layer of thick yellow clay subsoil pure enough to make pots with. If you have something similar, then you may be in the same scenario as we are. Though clay is generally seen as a problem, where ponds are concerned it can help solve problems instead and the water that is causing you difficulties could be put to good use  keeping the clay-lined pond topped up.

ShepherdsBarn

robairdmacraignil The ground is a little higher in the field beyond, but not considerably. Before we re-instated the pond it was always full after heavy rain but empty in dry weather; clearly we wanted to install a pond that was available to the wild life all year round which is why we put in a pond liner (admittedly, we didn't make a brilliant job of it). There is a drainpipe (approximately 4" in diameter) that runs from the pond area down to the front garden and into a drain. Water can be a nightmare during heavy rain!

Buttercupdays
Yes we did remove an old pond liner.
We live in a cob cottage ... so yes, we have heavy clay soil. I have not heard of 'puddled clay' it sounds interesting and I'd love to know more. Does it hold the water throughout the seasons?

Here are some pictures of the 'before' and 'now' ... well not actually now, but when it was finished last spring! We were so pleased with the result and delighted when, soon after, we saw 2 frogs in the pond ... too late for spawn then, but there is lots of spawn now ... and given the current situation, is not such a good thing! 

Thank you both for your replies.