Forum home Wildlife gardening

Help with a very neglected wildlife pond

Hi, We have moved to a house with a wildlife pond and knew the path around it was starting to collapse. Now that Autumn has arrived we want to make a start on the path. However, the problem has got much bigger than we thought. The pond was originally constructed approx 15 - 20 years ago, but the previous owners to us have not done anything for about 8 years. Our rear garden slopes and drains into the pond and we live in an area with high rainfall. The pond is elevated and half of its circumference is retained by a mud bank. When the pond has been filling the water level has rising above the level of the pond lining and seeping into the surrounding garden causing the path around the pond to collapse. We started the project by draining the pond in order to repair the path and the retaining walls. We are assuming there are no splits in the original liner. We are now left with very thick brown sludge about 2 foot at the bottom and looking for advice on whether to: empty pond as much as possible and fit new liner on top of old liner; remove original liner and start again. I have attached a video and some images. Any advice greatly appreciated.


  • if it was me i'd drain, dig it out and replace the liner, as you don't know how old it is and liners have a limited lifetime.
    it would give you the opportunity to make it bigger if you wanted, as well as fixing the drainage problems - you might want it overflowing into a bog garden/wet garden - for which you can use the old liner (you want it a little leaky)
    but make sure you keep two or three buckets of the gunk from the bottom as this has all the good bugs and bacteria ready to kick start your new pond into life
    and keep an eye out from hibernating frogs and toads as they can overwinter at the bottom of a pond in the mud
  • Thanks. This is really helpful & that's what we'll do. We started draining the pond and because it rained last night it was almost full again this morning. Pump is working well though and emptied again today. We've worked out why it fills up and where the drainage issues are, so it's going to be a challenging project against the weather. One solution to put in a French drain and stop the excess rain water going into the pond. If we can get the pond empty ASAP we thought about putting in a new liner (over the old one) but bigger to go under the path and once its in place we can work on the path and french drain. The pond will then fill up but a new liner in place. Does that sound like a good plan? Also the pond liner we require is 10m x 10m but not sure what to go for. Do you have any suggestions/recommendations. Thanks. 
  • Hello. My husband and I (novice gardeners) made made a wildlife pond this year out of a previous (pristine and totally wildlife-free) koi carp pond.  I was given useful tips from a really experienced pond-owner which I'd like to share, to help you:
    We decided to take the old liner out so that water didn't get trapped between the old liner and new one: we soon found that the water table was much higher than expected. So : when you put the new liner in, treat it carefully and don't trim away any of the edges until you are 100% sure of the final size you want it to be. 
    Then, after you put the new liner in, fill it 1/3 with water and leave it a week or 2 to "settle in". Then add more water - to maybe 2/3 full, and leave it again.
    The liner will shape itself and stretch a bit, so it needs to "find its own level". The best things we added are a big log-pile on one side for lots of creatures who like a damp home, and a sloping "beach" of various size pebbles and rocks. So far, we have a couple of frogs, a toad, loads of dragonflies and a variety of beetles/bugs in the water.
    Only downside? Our 6-month-old kitten fell in the pond when she tried to catch a fly. But she learned to swim (!)  Good luck to you and we hope it's a great success!
  • I should have added - this is my first-ever post, so i hope I've done it correctly :)
  • Hello Diana, thank you so much for your response to our pond problem. Taking the old liner out makes so much sense for a number of reasons 1. We really don't know how old it is and now we have started to drain the pond the liner was never taken high enough i.e. when the pond is completely full the water seeps through the pond wall (where there is no liner) and that's why the path has sunk. 2. We are never going to empty the pond fully (we drained it as much as we could and it rained over night and almost full again) as there is about 10 years of sludge at the bottom!! So, the only way is to remove the old liner (as you recommend) and leave the hole to drain naturally. This will give us time to sort out the drainage in the garden and stop the excess water getting into the pond every time it rains. As you say getting water between the old and the new liner would be a disaster!! I was lucky enough to speak to the owners who put in the pond originally when they visited the village in October (we live in Arisaig) and he was SO upset when he heard how much it had been neglected. I have great vision and can see in my mind how it will look again in a few months. The neighbours have also told us that a heron and otters were visitor's to our garden in the past. How exciting is that. Thanks 😊 again for your message. Alison 
  • fidgetbonesfidgetbones Posts: 17,441
    I had to empty my pond, I also had loads of sludge. I stuck it on a flower bed adjacent. It made really good fertiliser, the Nicotiana sylvestris were huge.
  • You shouldn't place a pond in the lowest part of the garden as it has nowhere to overflow and drain away to unless it can in some way be plumbed into a soak away or drain by way of an overflow.  If you want to leave the pond where it is work out a way of getting excess water to drain away.  Heavy prolonged rain, sudden downpours etc.
  • I built two small ponds next to each other in my previous garden. I made a rockery around them and had a few fish in each. There was always wild life around them so when I moved, a friend took on my fish. Acouple of years later I went back to visit a neighbour who told me to look over the fence at whatthe owners of my house had done witht the garden.
    Big mistake.
    There was a huge concrete monstrosity of a pond with Koi carp in it and a single row of standard roses planted around the edge of the garden. Nothing else. 
    I had to remind myself it was no longer "my garden".and everyone has the right to do what they like with their land.
    The odd thing is, when the couple viewed the house it was the garden which sold it to them. Ah well, each to their own.
  • Ferdinand2000Ferdinand2000 Posts: 537
    edited December 2020
    If you want to drain it, why not just poke a hole or six in the bottom of the old liner with a screwdriver?

    Or make it 20mm up one side if you want it to stay damp at the bottom?
    “Rivers know this ... we will get there in the end.”
  • How are you getting with your pond? Have you got any more pictures?
Sign In or Register to comment.