The UK’s first man-made freshwater public bathing pool is an excellent example of what Amanda Burden, the former New York City planning commissioner, means by “lively, enjoyable public spaces are the key to planning a great city. They are what makes it come alive.” She has an inspiring and insightful talk on TED here. Read below the details of how an experimental pond—part art installation, part leisure project—became a slice of biodiversity in the heart of Central London’s largest mixed-use development, proving that a holistic partnership between lateral-thinking developers, designers, and city planners can regenerate public open spaces for the common good.
 

OF SOIL AND WATER: THE KING'S CROSS POND CLUB
'Of Soil and Water: The King's Cross Pond Club', located on the King's Cross Central Development construction site in London, is a micro-ecological environment with a natural swimming pond at its centre. The temporary available land is transformed into a place where visitors can take a swim next to aquatic plants cleaning the water.
 
THE POND
The pond consists of three different zones: a swimming zone, a regeneration zone and a plant-filter zone. The water is purified by a natural process using water plants, nutrient mineralisation and a set of filters on the edge of the pond that supplement the natural filtration. The pond is free of chemicals. When it is being cleaned, the water loops back to complete the water cycle. This is a closed-loop system. However, the loss of water through evaporation is automatically replenished from the main water supply, which is also filtered. The daily number of bathers is restricted by the amount of water the system is able to clean. Thus, the use of the pond remains in balance with what nature can absorb and regenerate. 
 
THE SOIL
The soil zones around the pond range from an area of meagre soil and pioneer plants to a meadow area of rich soil where lush grass with wildflowers and shrubbery. The plants are chosen according to the specific types of soil. As they grow at their own pace, they clean and enrich the soil. Here, day after day, season after season, year after year, visitors can observe, experience and enjoy an environment rich in biodiversity. 
 
THE NATURE THEATER
The enclosed site presents the natural environment in miniature, a landscape in motion, a theatre of ecological cycles: the water cycle, the plant cycle, and the soil cycle. It is a mise en scène of the processes that occur between humans, water, soil and plants. All life starts in water. Plants move from water to land; they grow and move across the land, fertilise the soil, and eventually die. The sensual experience of swimming in the pond allows people to enter the narrative of the site with ease. By swimming, walking around the pond, playing and resting on the grass, visitors participate in a living laboratory that reveals nature's ability to restore itself. The project gives them the opportunity to learn about the resilience of the ecological system through their own direct experience.

THE STAGE OF THE ANTHROPOCENE 
When we swim, we feel weightless and free. It is a rejuvenating experience. By dipping their feet in the water and taking a swim in the man-made natural swimming pond, visitors effortlessly enter into dialogue with the Anthropocene Age. This term refers to the current geological age in which human activity profoundly changes our relationship with nature: we become co-creators of new natural processes. In 'Of Soil and Water: The King's Cross Pond Club', the pond is a relational object, creating a relationship between swimmers and the ecosystem of the site.
The elevated pond becomes a stage where the swimmers perform the balancing act of coexisting with nature. From this stage, they can watch the evolution of the surrounding neighbourhood and the ever-changing city, where new possibilities and new possible futures are being born.
 
THE CLUB 
Everyone is welcome to swim in the pond, but the number of people who may enter the site is restricted; it is calculated according to the capacity of the water filtration system. Visitors must agree to certain house rules, such as showering before entering the pond. Here, the joy of swimming combines with awareness of our responsibility toward the environment. The Club not only facilitates the building of community; it uses community-building as a tool to develop a more resilient liveable city.
 
THE PUBLIC ART PROJECT
'Of Soil and Water: The King's Cross Pond Club' is the first public man-made swimming pond in the United Kingdom; it can accommodate up to 163 bathers per day. Living with water is an ingrained part of London's everyday life. The King's Cross Pond Club is a public art project commissioned by King's Cross Central Limited Partnership. The project was initiated by the 'Relay Art Program'.