Keeping up with the growing popularity for natural swimming pools, Herzog & de Meuron has completed a biologically filtered bathing lake in Riehen, Switzerland.
Following a series of unrealised proposals for conventional swimming pools in the town, Herzog & de Meuron developed the design for the Naturbad Riehen in the spirit of Badi – the traditional wooden pools that sit within the Rhine river.
The result is an outdoor pool that offers bathers the experience of swimming in a naturally filtrated lake, kept clean using water plants as well as layers of gravel, sand and soil, rather than with machinery and chemicals.
With regards to both form and performance, the ‘Naturbad Riehen’ is treated as a natural pond rather than a standard swimming pool. Its edge takes an irregular and vegetated boundary, with various methods for guests to enter the water. These include a gently sloping gravel beach, staircases, as well as wood docks which allow for a jump into the small lake.
Functionally, the scheme replaces technical systems for biological filter terraces, which eliminates the use of chemical additives. the process is modelled after the natural terrestrian water purification through layers of gravel, sand, and soil.
Treatment machine rooms vanish, and water basins are located outside the facility boundary embedded in a sloping landscape across the road. With respect to the system’s ecological cleaning capacity, the baths are able to accommodate 2,000 guests per day.