Natural Swimming Ponds (how to build one)
Natural swimming ponds are not for everyone, but if you have the space, skills and inclination, they are an alternative to chlorine-filled private swimming pools. Natural plants and filtration keep them clean, and they blend in with local landscapes, and enable you to swim naturally, even inland!
Read our post on greener swimming costumes.
Use sloping sides in ponds, to avoid drowning hazards for wildlife. Read up on pet-friendly gardens, to know toxic plants (like water lilies) to avoid (blue-green algae is very toxic to pets). Dogs can also get cramp when swimming, ask your vet about suitable lifejackets.
Also read our post on wildlife-friendly ponds. For conventional swimming pools, keep the cover on when not in use, and use FrogLog (a ladder to let small critters escape) and Critter Skimmer (rescues trapped creatures), how many you buy depends on pool size.
Note that wildlife ponds are not the same as fish ponds (fish are carnivores that eat wildlife). So like wildlife ponds, natural swimming ponds are free of fish (carnivores that eat wildlife). Swimming ponds are also kept free of aquatic vegetation by an internal dividing wall.
There are many companies that offer good advice and services:
- Gartenart uses standards required by the more stringent German swimming pond association, used by thousands of private swimming pools in Europe.
- The Swimming Pond Company has a show swimming pond in Norfolk, and offers conversion of conventional swimming pools (costs around £100,000). It says that when removing blanket weed during months, care must be taken to allow wildlife caught in it, to return to the water.
- Natural Swimming Pools offers ‘pools without plants’, if you simply want a pool but without the chlorine. Using an award-winning ‘Living Pool System’, biological filters naturally extract phosphorous, and an automatic robot cleans the pool each day (they can also be heated). These pools promise not to turn your hair to straw or go green!
Tips for Building Natural Swimming Ponds
Natural swimming ponds are not for everyone, as they need land, skills and are expensive. But we are talking here about alternatives to chlorine swimming pools, which use one of the world’s most toxic chemicals to every living thing.
And though we may not live in luxury, many people do and have pools in their gardens! Although only around 4% of people in England have garden pools, that’s still around 250,000. Most are in southern England, due to higher incomes and warmer weather.
Obviously care must be taken on how pools flow into neighbouring gardens, and impact on local wildlife.
You’ll need to ensure the right type of soil, for best results. Sandy and gravel soils drain quickly, but don’t retain water easily. While clay soil holds water well, but has poor drainage. Adaption many be needed, and ponds should be sited away from trees that could affect structure and sunlight.
Swimming zones should be safe yet deep enough to swim, with suitable (pet-safe) aquatic plants and biofilters, with sloping sides and easy maintenance.
You will likely need planning permission to build natural swimming ponds, and also check on restrictions, and laws on protected species and habitats nearby.
Swimming ponds have a regeneration zone where reeds and rushes are planted, to naturally absorb nutrients to prevent algae. You’ll also need some kind of circulation pump to move water from the swimming area through filter beds and plants, then back to the pool.
Finally, think of landscaping for shade and sun, seating areas, and soft lighting (solar-powered options that go off when not in use are good, to prevent light pollution). Choose warm orange hues over white or blue, that is less harmful to birds and wildlife.
Plants will also need to be trimmed regularly to encourage fresh growth and overcrowding. Fallen leaves also need to be raked, to avoid them sinking and rotting, which could cloud the water.
Excess water may also need to be drained after heavy rain, to avoid flooding low garden ponds. And in hot weather, pools may need to be topped up with clean water, to protect plant roots (a gauge can help track water levels).
