NATURALLY FILTERED SWIMPONDS AND SWIMMING POOLS

A swimpond is a natural swimming pool similar to any kind of pool or lake where water quality is maintained by natural processes.   No chemicals, harmful to life, have been added.

Swimponds are kind both the users and the environment, and compared with traditional swimming pools, offer a more healthy and more invigorating swimming experience.   Swimming in one is like swimming in a lake or the ocean, except  it is in the privacy of your own  garden where you can soak up the minerals and oxygen in beautifully clear, clean, water.  And unlike any conventional swimming pool, a swimpond integrates fully into the garden and wider landscape.   Constructed on the principle of a wetlands eco-system,  a swimpond naturally attracts wildlife.

It’s no surprise that health-conscious people are evaluating the benefits of a swimpond over a traditional swimming pool. The idea of started in Germany, where hundreds of naturally filtered swimming pools have been installed.  Now, in Canada, there is growing interest.

How is a swimpond different to a traditional swimming pool?

A swimpond is similar to a conventional swimming pool in that it has a deep water zone dedicated to swimming. The essential difference is the method of filtration used to clean and sanitise the  pool.    Water contains nutrients which need to be kept to a minimum to prevent the growth of algae in swimming pools.    Algae can only be destroyed chemically with chlorine based swimming pool “shock”.  Shock is a granular form of concentrated chlorine, which rapidly increases the chlorine level of the swimming pool water. The raised chlorine level creates pool water conditions that kill everything organic.  “Shocking”  the pool has to be done on a regular basis.  The pool water also has to be changed about three times a year and emptied completely during the winter months.

In comparison, a swimpond is a biological system with a  more complex filtration system than merely  introducing poisons to the water.   It is designed with two separate and distinct areas.  One area is dedicated to swimming and built along the same lines as a conventional swimming pool, typically with near vertical sides and a deep end for diving.  The other part is a regeneration zone consisting of gravel beds and plants through which the pool water passes.

As the water passes slowly through the gravel beds, it is cleaned and mineralised as the gravel filtration system removes phosphates and other nutrients which support algae and other micro-organisms. Plants growing in the gravel also compete for nutrients further reducing levels of algae at the same time oxygenating the water and helping to maintain the right balance in the water.

Won’t I be swimming in frog spawn?

It’s true, swimponds attract wildlife.  That is part of the enjoyment and value.  But it should not interfere with your swimming experience.    Wildlife will prefer the shelter and food resources of the planted regeneration zone.   The swimming pool area cannot grow plants because is too deep and there is nothing for plants to root into.   Without plants, other creatures could not survive either.

Designing your swimpond

The design is influenced by the purpose of the pool.   It can be the length of a standard pool for swimming lengths with sufficient depth for diving.    The swimming zone can even be indoors.

Various factors have to be considered: the geology of the site,  source of water,  choice of materials,  design of the filtration beds and the development of the right aquatic environment.

The important thing to bear in mind is that your swimpond will be a permanent feature which, when not in use,  will look like a natural pond even in winter.

Andrew Lewis is a Biologist and experienced Garden Contract Designer.    He can be contacted on  (++1) 250 653 4770.