Borden Park Natural Swimming Pool
The Borden Natural Swimming pool is the first chemical free public outdoor pool to be built in Canada. The project replaced an existing pool with a seasonal pavilion and landscaped pool precinct for 400 swimmers.
Pat Hanson, partner at gh3*, told PREMIER CONSTRUCTION: “The City of Edmonton conducted a series of community consultations with the surrounding residential areas, and a natural pool was a request that came out of those consultations. To meet the requirements of two cubic metres of water per person, we were tasked to create an 800m2 adult pool to accommodate 400 swimmers.”
gh3* were challenged to create a large-scale pool with high-quality water control (a criterion essential for any public bathing facility), while also achieving an environmentally healthy and natural filtration process. They began by establishing a pool technology that cleanses the water through stone, gravel and botanic filtering processes, and this inspired them to create a materials-orientated concept for the change room facility that achieves a technically rigorous and aesthetically integrated design.
Canada’s guidelines for public pools are some of the strictest in the world, so to realise the project the architects needed to take a creative approach, classifying the project as “recreational waters” with the building permit as a “constructed beach with variances” – and the variances were the pools. The pool involves a balanced ecosystem where plant materials, microorganisms and nutrients come together within a gravel and sand filtering process to create “living water.” There is no soil involved in this process. Filtration is achieved in two ways; by means of a biological-mechanical system to the constructed wasteland and gravel filter, and in situ, with Zooplankton. This is an unsterilized, chemical and disinfectant free filtering system in which isolating membranes contain water as it circulates and is cleansed by means of natural processes. The processes take place at the north end of the pool precinct. On deck, water passes through a sand and stone submersive pond and a planted hydro botanic pond. Adjacent to these ponds, a granular filter PO4 adsorption unit is enclosed by the gabion walls continuous with the building.
The building houses universal changing rooms, showers, washrooms, staff areas and the water filtration mechanisms. The swimming program also includes a children’s pool. A deep pool, on-deck outdoor showers, a sandy beach, picnic areas and spaces are also included for other pool related recreational activities.
Pat said: “The use of the natural materials was our interpretation of what a natural pool could be. A natural pool is filtered through granular or water, so we took that as inspiration and developed a synergy between the water cleansing elements and the constructive material qualities of the building.”
The project’s materiality creates a fundamental conceptual connection between the technical demands of the pool and the design of the built enclosure and landscape elements. The dark limestone and steel of the gabion wall construction defines the enclosure’s vertical dimensions as filter-like or breathable, as granular and porous. The pool precinct is defined by a planar landscape where flush to surface detailing creates seamless interfaces among the sandy beach, the concrete pool perimeter and the wood decking. The gabion walls of the low rectilinear building terminate with a lid-like flat roof that frames the tree-canopy of the Park beyond and enhances the sensation of open-sky spaciousness within the pool precinct. The elemental form and reductive materials ease the use experience and enriches the narrative of bathing in the landscape. The juxtaposition of the
constructed elements invokes comparisons with the geology of the North Saskatchewan River and the flat topography of the prairie lands edge.
The building takes a cue from the two adjacent mid-century modernist style pool buildings. Built in the 1950s these extant buildings define the southwest edge of the pool precinct and connects the new with a century old cultural heritage of architecturally distinctive, civic outdoor bathing pavilions.
The Borden National Swimming Pool is indicative of the City of Edmonton’s exemplary leadership and recognition of the civic importance of architectural excellence in the building of public infrastructure. Borden Park has evolved over the last century as a place of shared outdoor recreational activities, as a destination for family gatherings and for outdoor bathing since 1942, as well as playing host to a zoo and at times fairground and events. Borden Park holds immense civic value and social significance for the surrounding communities and for North/East Edmonton. The project contributes a signature landmark element within the on-going transformation of the historic landscape of the Park.
Pat concluded: “For us, we are both architects and landscape architects, so the project was always interesting because it was an opportunity to integrate architecture and landscape architecture into one project. It was a great opportunity to develop a project that used the lens of landscape and architecture to develop an idea of a place.”