Discussing why a pond liner is required and looking into the original pond liner method - clay
Pond liner is essential to prevent pond water seeping away. This article provides notes on the different types of pond liner currently available. Once you have decided what type of pond you want and where you want to put it the next decision is how to line your pond. You need a barrier to stop the water draining away. There are many different types of pond liner on the market. further articles will look at each pond liner method in more detail, here we try to provide a quick overview of the original clay method. This approach is less common as modern flexible pond liners have become cheaper and more widely distributed. However, it’s always useful to reconsider the past and clay-lined ponds are considered to be the most natural method of all. They use no synethic materials and make use of natural product already available in abundance
Puddled Clay
Years ago before modern methods of pond liner had been invented the base of a pond would be ‘puddled’ with clay. "Puddling" means to compact the clay to squeeze the air out of it – this leaves a densely packed material which forms a watertight barrier. In years gone by this was achieved by cattle but it can also be achieved by human feet, hands and tools. This is a very messy and time consuming task and often prone to leakage especially if the clay is allowed to dry out should water levels dip. This is a method rarely used nowadays although puddling clay is still supplied by UK companies – expect to pay approx £40 for a single tonne to £5 per tonne for hundreds of thousands of tonnes. As these numbers suggest puddling clay is usually the preserve of large civil engineering projects such as waterways. The clay needs be laid at a depth of 20-30cm (8” to 12”). The clay must be compacted very hard – a good tool for this would be a plate vibrator or ‘whacker’ plate.
The creation of such a natural pond is a very noble action but we suggest that this is a process best avoided. Problems can occur which may need a specialist to sort. Pond liners are relatively inexpensive nowadays and we believe that they are carbon positive - the beneficial act of building a pond far outweighs any damage to the environment by the creation of the pond liner itself. It could work to buil a clay pond but consider a man-made pond liner as a fall back position (if water leaks cover the clay with a pond liner after).