Garden ponds and pools affected by your garden style


So what are the characteristics of these materials and how do they perform in certain situations?

The small informal garden pool.

In terms of the thinner materials, 0.75mm butyl rubber has always been considered the ‘Rolls-Royce’ of materials. It folds well into place and has a certain stretch-ability or give that finds the contours of the smaller awkward shape. It evolves a certain patina over time that gives it an almost natural stone look and for some people this may be a disqualification.

For people keen on cleanliness and godliness, they will find PVC and Polyethylene easier to clean. EPDM rubber is too thick at 1mm and folds awkwardly in tight spaces.

Some of the more robust PVC and Polyethylene don’t seem to want to fold down at all and you end up holding flaps of liner down with planting baskets.

Large garden ponds and pools.

In my experience, as long as the size is within a dimension that can actually be transported to site and then the rolls of material manoeuvred to be laid, EPDM rubber performs as well as butyl. It is much heavier because it tends to be thicker for the same resilience value, but this gives it the ability to smooth itself out to a certain extent as the water fills the pool.

With butyl and PVC the folds become exaggerated as the weight of the water takes effect.

EPDM is quite resilient to puncturing, but not as resilient as butyl to impact, as from heavy stones.

PVC is not good with impact but on the other hand it is very difficult to pierce with gradual pressure as from a blade or spike. All these idiosyncrasies are evened out with a good layer of sand under the liner as well as a fabric underlay. 

It is interesting to note that for the construction of wildlife or conservation pools, the BTCV, the national conservation volunteer group, use EPDM rubber in the ponds they create all around the country, some in areas exposed to spates of vandalism. These have the added protection of a geomembrane on top of the liner as well as below and then perhaps a 15cm a layer of subsoil over that.

Very large pools need to be welded from strips on site because of the weight factor. EPDM has to be factory welded. Butyl and PVC can be welded and polyethylene can even be taped. Polyethylene has a poor reputation from the past to live down and although it is very popular in other continents – in South Africa they use nothing else – I would be very averse to using it on a large project.

Mainly because of its price, farmers love it in the UK using it for everything from silage pits to slurry lagoons. 

When price becomes the crucial factor on these large sites, butyl cannot keep up.

Over the years the prices have been falling on all the products as the alleged performance goes up, but it has now reached a point that butyl can no longer compete particularly when it needs to be 1mm or over.

Stream and waterfalls are projects with which I always prefer to be using butyl.

Creating them using natural stone and cement, theoretically the stonework should be self supporting, but there is a bit of grip that you get from butyl rubber and cement mortar that ensures that it says where its put until it goes off. As I’ve said before, it has resilience to stone impact, which served me well when I was building waterfalls before the idea of protective underlay over the liner was ever thought of. 

Other factors that may have relevance are: 

Weather conditions.

PVC does not perform well in extremes of temperature. In the very cold it can crack if it is folded tightly. In extreme heat it can become very flimsy. These are only factors that affect its installation. Once it is installed, it seems to be ok.

Root penetration.

PVC seems impervious to the most rampant plant growth from willow to bamboo, from bindweed to Japanese knotweed. As for butyl especially when it ages, some plants seem to sense there is water the other side of it and head straight through.

Burrowing beasties

Mice and moles have only affected butyl installations from below in my experience. It may be just my experience, but I will ‘throw it into the hat’ for consideration.

Extending pools and water garden ponds

I might have given you the idea that because you can weld PVC and butyl on site that you could easily extend your water garden at a future date. Unfortunately the welding machinery is difficult to come by, even more difficult to use on dirty pond liner and simply does not work on butyl that has been in the ground for more than a year. PVC I would not like to vouch for, but by the time you have had skilled contractor in to assess and do the job it will probably be better to have a completely new liner installed.


The ultimate choice must be down to availability and price. If you have a supplier on your doorstep, or there is a price in a magazine or on the Internet from a reputable company that suits you, then go for it. The important thing is that it is suitable for the project you have in mind. Here are 10 top tips to bear in mind in your budget considerations.

Garden water feature:fountain

Perhaps it is time to add a bit of life or sparkle to your water garden scene with a fountain, to give it that eye-catching appeal that demands your attention. Maybe you want to give the fish a view of their surrounding.

It may be that although there is a mass of the right sorts of plants, the fish are other verge of overcrowding and a little bit of technology in the form of a filter and possibly an ultra violet clarifier would help keep things cleaner, clearer and a more healthy environment for the fish. Possibly you want to add the drama of a waterfall or a cascade, even incorporate all four together.

Whether you want to incorporate them in your new water garden scheme or add it to an already existing pool, the most suitable equipment for whichever purpose can seem a little confusing at first sight, even to those of us familiar with the stuff. However there are number of rules of thumb that have always applied to these things and using them will help you feel confident in buying the right equipment for whatever effect or purpose and that it will be suitable for the task you put it to. 

The water garden trade and industry have moved on apace over recent years and some companies have recognised that here is a market that deserves products that have been designed and developed properly. The result is that products look new and very different and there is a lot more choice from a number of manufacturers competing in the market, providing confusing arrays of size and performance within their own ranges.

Although these products do the same job perhaps more efficiently, many of the same principles involved in their performance will still apply. 

For instance, if you want a waterfall coming into a pool and you want that pool to be a stable environment for fish and plants, then you should not recycle more than the total volume of that pool in one hour down that waterfall. Therefore the pump you choose should be capable of delivering the right amount to the prescribed height of your waterfall above the water level of the pool.

Want to know more? You probably know a lot of them already. You will pick up a lot of them on the side of product packaging, but once upon a time these rules were just unwritten canons for the ‘streetwise’ initiates and you only painfully learnt about them when you dared to confess all your ‘cock-ups’ at the local water garden product outlet – probably some grubby ‘lean-to’ in the back of beyond inhabited by zealous workaholics with manic staring eyes. Well here are some of their secrets, which if they are not common knowledge now, they should be, because they are essential in trying to budget for a scheme.

Pond and water fountain pumps

Water pumps are pretty much the key to the operation of all water moving activity in the pool. For the most part consider submersible pumps and look for something that has been specifically designed for use in water gardens. Even though they might use 240 volts of electricity they are quite safe to use as long they are ‘plumbed in’ to the power supply through a RCD isolating trip switch that is on a separate mains loop from the main domestic supply.

For small pools with tiny waterfalls or just simple fountain effects there are excellent 12volt submersible pumps on the market. 

Pond and feature fountains

Water fountains create a focal point and animate a dull area of the garden. The sound of a big fountain can drown out most ambient noise, of things like traffic and other people talking and so they are great in city gardens and private spaces. They are also great aerators of water, helping sustain any animals or fish that in habit the water below. But if you were thinking in terms of these beautifully engineered tubes of steel and brass that seem to make water dance all but the ‘Sugar Plum Fairy’, then save up you pennies. Fairly simple devices start in the hundreds of pounds and as for the stunning machines that launch mortar rounds of pieces of water, you are talking in thousands of pounds.

Fountain features that have no visible water reservoir or pool in which they sit need to be sterilised in some way with a strong algicide that may be chlorine based or may contain potassium permanganate or copper sulphate. Certainly not anything that could be described as fish friendly. With water running over the ornament surface, or landing surrounding surfaces, algae and moss soon establishes itself to give an aged or rustic look out of kilter with the clean shiny looks of minimalism.

Fountains are fish friendly and fountain in pools with fish in, need to be easy to maintain. So make sure you have a method of reaching them from the side of the pool because they will regular clog with lime from the water or detritus pumped up from the pump. If they are too light and they are in an exposed position, the spray can easily be blown out of the pool. Ensure there is at least the height of the fountain spray times two from the fountain jet to the pool side.

The gushing style or foaming jet is a useful aerator that is less liable to be windblown. The really effective versions of these are quite expensive, because they are engineered to suck in air as they rise up. What is more, they need a good powerful pump to be effective. If you have a pump, it can be a fairly effective compromise to have just the fountain nozzle, minus jet, spurting up full bore from just below the water surface. This seems to create aerating bubbles without too much spray.



It will help your Aquatic retailer if you can be sure of what you want you water garden pump to do. Assuming you will want a submersible pump because they are the most efficient and cost effective for the price, here are a number of factors you and he will have to consider.

1.The cost arises before the pump is in place. Do you have power out to the pool or water feature. Doing the job properly with armoured cable and waterproof junction boxes can easily outstrip the mere cost of the pump. Also do you have RCD trip switches installed to isolate the pump from the domestic mains.

  1. The above question leads onto safety, even though all electrical connections must be up to professional standards, many people with young children are still frightened of putting a machine running of 240volts into water a child might put its hands into. There is a huge range of low voltage pumps that can produce quite adequate performance for most domestic water gardens for very little extra cost and in total safety. You just need to find somewhere to put the transformer. 
  2. What do want the pump to do? Will you want it to run a fountain, waterfall and a biological filter? A biological filter needs to be fed the total volume of the pool every two hours. So you must know the volume of your pool. A rough guide is adequate:

(LENGTH x WIDTH x DEPTH) in metres x 1000 = Volume of the pool in Litres

The pump should be capable if pumping half that figure to an appropriate filter. If the pump is to run a fountain as well then you need possibly 1000 litres an hour extra for that. Gushing frothy fountains may need a lot more. Waterfalls need at least 10 litres per hour for each centimetre width to the required head of the waterfall. This translates to 60 gallons per hour per inch.

4.For filter pumps. Is it capable of handling solids? A fine sponge pre-filter may help protect delicate bearings but it doesn’t allow much muck to get through with an all too regular wash out.

5.For filter pumps in particular, is it ‘continuously rated’? Does the guarantee cover it for running non-stop.

  1. Fountain pumps with fine rose jets need a good pre-filter on the pump otherwise you are forever cleaning them out. 
  2. For waterfall pumps and filter pumps, looking on the performance table, is the volume of water you require to the height that your filter and waterfall header pool sits well within the 40% -80% of it maximum rated flow.
  3. The costs of the pump can be easily outstripped by the costs of running it. A good motor that is capable of shifting 1000 litres and hour can be as little 15Watts.
  4. Has it got all the fittings you need in the box? If you need extra fittings they can be quite expensive.
  5. Is it easy to take apart and put back together again for ease of maintenance on a cold autumnal morning?