A natural swimming pool does not use chlorine, biocides and other chemicals that can be harmful to human health. Natural swimming pool water is kept clean using plants with the help of micro-organisms living in the stone plant growing medium. The treatment takes place in a separate or connected shallow regeneration pool.
Natural swimming pools can aesthetically look like a traditional swimming pool with a separate regeneration pool or the regeneration pool can be designed to look like a natural pond by incorporating the regeneration planting into the swimming pool design.
How The Water Is Treated:
- Perforated pipes are placed on the bottom and covered with expanded shale or washed stone.
- The washed stone serves as the plant anchor for the aquatic plants forcing them to draw their nutrients from the water and not the plant medium.
- The plants absorb bacteria and pollutants from the water.
- A small, energy efficient pump is used to circulate the water from the perforated pipe and skimmer back to the swimming area.
- The water discharged from the pump to the swimming pool provides an opportunity to add a water feature such as rock falls. This feature will aerate the water and provide water movement to prevent stagnation and reduce the temperature of the water.
- Plants also shade and reduce the temperature of the water.
- Circulating the water reduces water stratification that will cause algae growth in the swimming pool.
- As naturally occurring in lakes, zoo plankton in the water feed on and reduce the algae in the pool.
- When the water is pumped from the regeneration pool it is drawn through the stone plant medium which filters the water.
- For sanitation an ultraviolet water-treatment chamber can be added to treat the recirculated water.
The initial installation of a natural swimming pool costs more than a traditional pool but the long term operational costs for chemicals will be substantially less.
Aquatic plants are selected based on the plant zone where the natural pool is being constructed. In northern climates natural swimming pools can be used for ice skating by simply removing the circulation pump.
The first natural swimming pool with a plant regeneration pool was constructed over 32 years ago in Austria. Since then over 29 thousand natural swimming pools have been constructed in Europe and South America countries. (Source “Natural Swimming Pools” by Michael Littlewood)
The first public natural swimming pool located in south Florida was constructed and approved by the Health Department at The Sunday House in Delray Beach, FL over 11 years ago. The Sunday House pool treats the water through a series of regeneration falls and tropical pools. Ultraviolet water-treatment chambers are used as a water sanitizer and algae eating fish in the swimming area help control the algae. (See attached photos taken by Urban Associates, Inc. information source article in Sun-Sentinel dated 7/5/2004)
Urban Associates, Inc. has recently designed a chemical free fountain with a plant regeneration zone and rain curtain used to aerate the water. Fill and makeup water for this chemical free fountain will be from a cistern supplied with water harvested from an adjacent roof.
For further information and assistance with the design of a natural swimming pool or fountain contact Leo Urban RLA, LEED AP BD+C at Urban Associates, Inc.
