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Small garden pond adjustment

Hi all! My name's Mike and this is my first post but I've been a frequent visitor to the forums and RSPB website to help make my back garden a haven for wildlife.

I built a small (approx. 2m x 2m) wildlife pond in West Wiltshire in the spring of 2017 and have had success attracting all sorts of creatures to it. However, it is too deep for its size and I would like your advice on lifting the liner up in order to make the pond shallower and increase its surface area whilst causing minimal disruption to wildlife.

Current issues:

1 - Steep banks (aside from one semi-slope) due to being 75cm in the deepest part. This causes the liner (butyl) to be exposed in several places and the roots of plants on the shelves are poking out into the middle of pond.

2 - High nutrient levels due to a mixture of top soil and clay I dug up to provide rooting opportunities for native plants inside the pond.

3 - Water level is 10-15cm below what it should / used to be either due to a hole in the liner or the rich plant growth around the pond's edges. Whenever the growth is removed the algae returns. As a result, there is hardly any overspill into the bog patch.

As briefly mentioned, my aim is to halve the max depth of the pond (to approx. 30-40cm) and use the spare liner to increase the pond in size slightly. Keeping most (or all) wildlife alive and not damaging the butyl liner are the main goals during the pond adjustment.

What's the best time of the year to carry this out? How best to go about it? Pictures to follow!

  • Hi Alpetrum welcome to the community from Sheffield.
    I would think you will have a major job on your hands to lift the liner up to reduce the depth and reuse it.
    Looking on the internet it isn't overly deep at 75cm www.aquanooga.com/Articles.asp
    Hopefully someone who has a pond in their garden my be able to give you some advice.

    My Flickr photos

  • Hi Mike

    I would agree with Alan that lifting the liner would be a major task if you don’t want the wildlife to be disturbed. 75cm is a decent depth for a pond as it allows things to retreat away from the surface if the pond is frozen. If you’re dead set on decreasing the depth, perhaps if you were to place boulders in the bottom of the pond this would also raise the water level and provide additional habitat for the various pond beasties. Perhaps the boulders could be placed in such a way to also provide habitat nearer the surface as well. If the liner is punctured then you’ll never be able to maintain the pond at full capacity. If this is the case perhaps placing some turf around and drooping intoward the pond would help to hide the exposed lining. Aquatic compost can also be bought at most garden centres and will allow plants to root without increasing the nutrient levels too much. I would also suggest plenty of oxygenators to help with the algae problem, and if the pond is open and exposed perhaps a water lily would provide some shade to also help prevent algae build up. I use this company HERE for my pond plants and have always found them to be very honest and helpful, they actually advised me not to buy particular plants due to my pond being unsuitable for them. They are very knowledgeable and helpful if you call for advice. I also have a rain barrel which I use to top the pond up when the level drops, always better than tap water which can be another cause of excess algae. Now would be a good time of the year to carry any work out as the main growing season is yet to come.

    My bird photos HERE

  • Hi Mike,

    We have a small pond in our garden, 292 ltrs max capacity, measuring approx: L=1.5mtrs, W= 0.5mtrs D=0.5mtrs (graduated sides with shelves for plants) , installed May 2002, and initially we had a lot of issues with water clarity.

    The pond is of the moulded liner type, which is tougher than a liner and less likely to puncture, keeping water and pond life in, and other garden growth in the garden.

    I'll make it quite clear here and now, I'm no expert, so all I've tried is based on advice from aquatic shops, internet and books purely on a trial and fail basis.

    It took a good few years before we managed to get things to stabilise, and around ten years ago after numerous failures keeping fish, I decided to clean the pond out thoroughly, then refill it and restock with fish.

    I also upgraded the pump with integral filter to one for a pond three times the size, and the end result has been prolonged keeping of fish and clearer water.

    Aeration is important towards clear water, and helping to keep the algae down, but it will not eradicate it, we still regularly have to clear algae out, especially during the summer.

    It could all be pure luck, I don't know, but there might be some tips for you to consider.


    Flickr Peak Rambler