Converting a conventional swimming pool to a natural one is easier than you’d think, says Michael Littlewood – and infinitely rewarding.
Imagine a swimming pool, and what do you see? A slab of sterile blue water, surrounded by tiles? It doesn’t have to be like that: imagine instead a pool of fresh, clear water, fringed by native plants and visited by dragonflies. The upsurge of interest in natural swimming pools, which I introduced to this country in 2000, has convinced many owners of conventional pools to aspire to a natural one. The good news is that converting a conventional pool is usually possible – and much easier and cheaper than starting from scratch.
When Mr and Mrs G. bought a house in an attractive North Wiltshire village, they inherited a conventional swimming pool, but they used it infrequently as it required regular and expensive maintenance. “We had three options,” says Mr G. “We could fill it in, turn it into a tennis court or convert it to a natural swimming pool.” I arranged for them to visit a pool conversion that had been carried out two years previously, and that made their minds up.
Natural swimming pools are beautiful garden features all year round – unlike conventional pools, which can be an eyesore, especially in winter. They stay clean without any chemical treatment, so they are better for you, better for the environment, and cost less to maintain. Instead, the water is cleaned by being filtered through a planted ‘regeneration zone’. The swimming area is separated from the plants, but you are surrounded by them as you swim – and this seamless blending of environments makes the experience very special.
Design
The garden consists of a series of outdoor ‘rooms’, with the pool situated in the north-west garden, approximately 50m from the house. It is enclosed by a natural stone wall on two sides, with an evergreen hedge on the third and a difference in levels making up the fourth. The space is a real sun trap and well protected from prevailing winds. Furthermore, the mature trees, shrubs and plants and the highly maintained lawn provide a sense of tranquillity and a strong feeling of being in a very secluded place.
Several design concepts were produced, and after much discussion we agreed on a design, which would see the pool reduced in size from 12 by 6m to 10 by 6m. A curved outer retaining wall to cope with the change of level encloses the pool at the southern end. In front a lower wall creates a raised bed, broken in the centre by a small waterfall. This bed contains the reeds and rushes which are the main cleaning plants for the system. The waterfall acts as the main focal point when viewed from the terrace. Opposite the existing stone steps, a small timber deck is positioned. Stepping stones of natural materials provide access through the pool at the far end and to the diving rock.
Construction
Anglo Swimming Ponds submitted the most acceptable tender and were awarded the contract, commencing work early in March. A particular requirement by the clients was that the work should have minimal impact on the rest of their garden – and there was also a time limit; the garden was due to be opened to the public as part of the National Gardens Scheme Open Day in June.
One of the many advantages of converting an existing pool is that most of the excavation work has been done, and all the main services, such as water, electricity and drainage, are already in place. This not only saves time and money but minimises disruption. In this instance, the existing pool had been covered with a liner, so it was quite a surprise when it was removed to discover a metal retaining wall, one metre deep, sitting on a concrete wall. Unfortunately this had to be strengthened before the new liners could be laid. The pool did have a bottom drain which proved very helpful, and it also had an inlet, skimmer and underwater lighting. While the actual equipment could not be reused, the cables and pipes could.
Once all the services had been installed, the steps and deck were constructed using artificial timber, providing a safe surface of enduring quality. The terrace of sandstone paving slabs was laid, and the boulders for the waterfall were manoeuvred into position. Finally the gravel substrate was placed into the regeneration zone, and this was planted up.
With the planting completed, the contractor had a considerable amount of finishing and restoration of the surrounding garden to undertake in time for the Open Day. That this was achieved in spite of some inclement weather is a tribute to Project Manager Steve Day and his excellent team.
Mr and Mrs G. say, “We are delighted with the outcome. This is now the most tranquil part of the garden, with the sound of the waterfall always in the background, and we naturally gravitate there. One surprise is how warm the water becomes naturally as there is, of course, no heating. The pond is very attractive, blends into the surroundings perfectly, is low maintenance, and is admired by all.”
Further reading
Michael Littlewood is a chartered landscape architect and the author of many landscape and gardening publications including Natural Swimming Pools – Inspiration for Harmony with Nature, Natural Swimming Pools – A Guide for Building and Converting the Conventional Pool. These comprehensively illustrated books are an essential resource for anyone considering a natural swimming pool, guiding you through planning, design, biology, materials, construction, planting and maintenance.
For full details and descriptions of the books, please see the publications catalogue at www.ecodesignscape.co.uk or request a printed copy.
