The Borden Park Natural Swimming Pool is the first facility of its kind in Canada. Engineered to purify city-supplied water with botanic filtering processes rather than noxious chlorine, the chemical-free “constructed beach” is win–win–win:

The easy-to-maintain system improves well-being and accessibility, lowers operating costs and creates new habitats for native flora and fauna. And the overall design allows it to do so beautifully, with a gentle shoreline-inspired pool slope and a low rectilinear change room building that translates the purification process into elegant, restrained architecture.

To fully appreciate the design, you must first understand the inner workings of the water-cleaning systems: a set of regeneration basins at one end of the pool deck (visible to patrons but protected by glass) and an adjacent bed of crushed granite concealed behind the building’s gabion walls.

Overflow from the pools circulates through these filtering elements, which contain cattails, water lilies, rushes and microscopic marine animals that remove human-introduced contaminants from the water. In order to work smoothly, capacity for the pools — which encompass a children’s pool and a deep pool — is capped at 400 swimmers at a time.

The building — a long, low-slung volume with a flat, lid-like roof — borrows from the materials of the natural systems, its full-height limestone gabion walls echoing the hidden granular filter processes. These walls facilitate natural ventilation, moderate indoor temperatures (via their thermal mass) and create a heat island effect in colder seasons. The structure features pivoting steel doors that rise to the height of the roof, which frames the tree canopy of the park beyond.

Within the building, the walls, partitions and millwork are built from marine-grade plywood rubbed with white and black staining to emphasize the grain; by contrast, the washrooms’ wall panels are cast from sleek Corian. An elegant ultra-minimalism elevates every aspect of the project, down to the cane-shaped chrome shower heads that poolgoers are required to use before they take a dip.

This natural swimming pool is one of many projects commissioned by the City of Edmonton for Borden Park, a number of which were also designed by Gh3*. The entire endeavour shows how public infrastructure can transform a city for the better — especially when it embraces architectural excellence.

Location Edmonton, Canada Firm Gh3* architecture (Toronto, Canada) Team Pat Hanson, Raymond Chow, Joel DiGiacomo, DaeHee Kim, Nicholas Callies, John McKenna and Bernard Jin with Chris Makortoff (EllisDon), Alejandro Ortega Garcia (Morrison Hershfield), Stefan Bruns (Polyplan) and Aled Jones (Associated Engineering)