The ultimate water feature guide Create sound and movement in your garden with a fountain, wildlife pool or rill Attractive pond in a small garden giving a natural appearance by a grass edge and backdrop of moisture loving shrubs and perennials Want instant interest? Just add water Photo: GAP Photos/Graham Strong By Bunny Guinness6:00AM GMT 01 Mar 2015 To my mind, water is the son et lumiere of the garden. It adds sound and light and also brings in life. Water features are brilliant for increasing the enjoyment of gardens – but only if they work properly.
I first consulted Nick Roberts of Fountains Direct more than 30 years ago on a complex series of formal cascades for a client and quickly realised that a water feature engineer (although his wife calls him “the plumber”) could save a lot of floundering. I asked Nick, who installed the Fountain Court at Somerset House, about the pitfalls that most of us encounter when we get creative with water for our own gardens.
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His first piece of advice is that it is important to design something you can live with and afford. A simple, informal wildlife pool can be stunning. It does not necessarily need fountains, sculptures or added glitz. You may not require or want the water to be gin-clear and can tolerate the odd few days in a hot, early spring when it may look like pea soup. Even so, you need the liner to hold water and you shouldn’t have to see it. EPDM (ethylene propylene diene monomer) liners (1mm thick) are now thought to be superior to butyl. I, like Nick, would always lay them over an underlay and then put another layer of underlay on the top for added protection. The underlay quickly takes on the sludgy colour of algae and disappears under a layer of pebbles or poor subsoil (rich soil encourages algal growth).
A wildlife pond can be an affordable and stunning way to add water (GAP Photos/Graham Strong)
To have a good pH balance with no algal outbreaks, ideally the pond needs an area of 400 sq m with a depth of 1.5m in places. My own pool is nothing like that, just 30 sq m. Generally it is well behaved, except in some early warm springs when we get blanket weed. Then I rush out and add barley straw extract (Aga Group) to control it.
Ideally, two-thirds of the water surface should be covered with floating plants (water lily, water soldier, frogbit) while three-quarters of the sides should be planted with marginal and emergent plants (water forget-me-not, flowering rush, marsh marigold). Weigh down bunches of submergent plants (such as spiked water milfoil) and throw them in. If the liner shows in places, coir sausages pre-planted with marginal plants are a quick fix (Verdant Solutions). These “natural ponds” never need cleaning. If the sludge gets pongy, add some AquaBio (calcium sulphate) in late summer from the Aga Group. Slowly the pond will become more healthy.
With any pool, if you want it crystal clear and to be able to see the fish all the time then you need a filtration system. That is, unless it’s just 200-300 litres and you are happy to drain it every couple of months, clean it and refill.
A filtration system is needed for crystal clear water (Alamy)
Nick says the Oase self-cleaning drum filters, which are either gravity-fed or pumped, are the best for amateurs. These must be installed outside the pool. He also reckons that if you put a fountain in a pool, it must look good when it is switched off. I agree, as elaborate figures pouring vases look strange when they are not working. A favourite of his is a Kadai fire bowl that sits in the centre of a circular pool and gently trickles over.
“If you want carp,” he says, “remember they dig up and remove everything, so the filter system has to be very sophisticated.” Generally, fish are not helpful for water clarity and it is easier to leave them out, though you will probably find, as with my father’s pool, that they just arrive. Five carp wafted in, probably as eggs on ducks’ feet.
I love rills in gardens. They can snake through in an informal fashion or can be used to add to the formality. Nick points out that the common problem with these is that the catchment tank (usually underground) is too small. It has to cater for the volume of water in the rill, plus that in the recirculating pipe and the volume of water required to cover the pump in the tank. Nick did one recently that was 90 metres long with a fall of 1:100. To create added movement in the water they put small triangular blocks on opposing sides of the rill every few metres so the water gave an attractive criss-cross pattern as it flowed through.
Rills can add a formal feel in a garden (Dariusz Gora / Alamy)
Water features lose water through evaporation far faster than is often thought. Nick has recently installed a polished black granite block, 1.3m wide and 600mm high, which has water trickling over it into an underground tank and back to the top again. It is in a windy site and so loses a copious amount for many months of the year. Automatic top-up units are now commonplace, using a solenoid valve. A sensor sits on the water line and triggers the pump to start. This usually costs about £600 to £700, but, by law, it cannot fill from the mains supply. It has to be from a “category five supply”, and installing the extra tank capacity might well cost £3,000 to £4,000. Filling with a hose is not such a bad idea!
Stainless-steel water walls were all the rage a few years ago. Quickly, inexpensive kits from China and elsewhere came on to the market. As Nick points out, you do get what you pay for with these. If you go for a budget version, site it so that any flaws are not obvious. As long as you don’t mind replacing elements such as the pump after a while, all is fine. It might well give you a lot of pleasure for not a lot of outlay.
As to Nick’s own garden, what does he have as his showpiece? Nick has a bubbling millstone (as does the Prince of Wales on his terrace at Highgrove). His firm sells them in kit form, a metre-diameter stone with a central thick foamy fountain jet that sits on a grating over a tank complete with an Oase pump (Nick wouldn’t have any other: remember, it’s a five-year guarantee if you fill in the form, otherwise only two) and LED lighting.
Millstones can make a strong garden feature (John Glover / Alamy)
“It may sound like the cobbler’s shoes,” says Nick. “But it runs from six to eight each day and I’ve cleaned it out twice and replaced the pump once in 20 years.”
If you would prefer some fountains in paving à la Somerset House, they are not difficult, he says. The paving must be waterproof, though, so the water is collected in channels. The cones that create the fountain jets pop up through the paving and there is an underground reservoir. Pay your money and take your choice