he first hint that there is something unusual about
the new outdoor swimming pool at Borden Park in
Edmonton, Alberta, is what isn’t there—that insidious
but telltale odor of chlorine. This is because the 64,000
squarefoot recreational complex, which includes a sandy
beach, changing rooms, and plenty of space to soak up
the sun, is Canada’s first “natural” public swimming
facility. Instead of using chlorine or other chemicals for disinfection, it
relies on the cleansing capabilities of sand, gravel, and carefully select
ed aquatic plants and organisms.
And the architecture provides its own subtle clues that something
is different here. Natural materials are combined with a minimalist
expression and inventive details to give the Borden Park Natural
Swimming Pool a refined toughness not normally associated with a
neighborhood swimming hole.
Designed by gh3 architecture, a Toronto firm whose practice encom
passes both landscape and buildings at a range of scales and types, the
$11 million project comprises two concrete pools that at first glance
seem mostly conventional: a small, shallow one for toddlers, and a
much larger, deeper one for older children and adults. Both are rectan
gular, with white bottoms and sides. But they are part of a planar
landscape. Regardless of the depth, the water’s surface is flush with
the deck all along the pools’ concrete perimeter, which in turn is level
with the expanses of sand and other areas finished in wood plank.
This plinthlike zone is defined by gabion walls of local limestone
that enclose a long, lowslung building along the site’s eastern edge
housing reception, staff areas, and a snack bar, along with the chang
ing rooms. The porosity of the stone walls—mortarless and held
together by metal cages—is a reference to the filtration process that
purifies the water, says Pat Hanson, a gh3 partner. Although the conT
struction method was famously used at Herzog & de Meuron’s late
1990s Dominus Winery, in California’s Napa Valley, it is most common
ly used for retaining walls and other civil engineering applications,
rather than buildings. Here in Edmonton, the permeable gabion walls
seem especially appropriate for a seasonal pavilion, one without a
mechanical heating or cooling system, Hanson points out. Not only do
they facilitate natural ventilation, but the thermal mass provided by
their 3foot depth helps moderate temperatures within the building
and just outside it, on the pool deck.
To accentuate the walls’ heft and materiality, the gh3 team has
deployed a number of visual sleights of hand. Within the stacked lime
stone, the architects have concealed the true vertical support system of
hollowsection steel columns, allowing the enclosure to read as weight
bearing. They extended the door and windows the full height of the
stonefilled 12foottall cages (nearly 3 feet above the interior’s ceiling),
framed them in steel plate, and pushed the glass far into the openings.
The assembly is topped with a caplike parapet, only 4 inches high,
belying the roof’s actual thickness. This set of decisions produces a
quiet, crispedged structure punctuated with deep shadows. “The
details highlight the elemental, rectangular form,” says Hanson.
The idea for a chemicalfree pool in Edmonton came from residents
of the neighborhoods surrounding the 54acre Borden Park, located 2.5
miles northeast of downtown and known for its meandering paths and
mature shade trees. Aware of the naturalpool movement—which first
gained traction in Austria in the 1980s and later spread to Germany
and elsewhere in Europe—they wanted to replace the park’s rundown,
1950sera pool with an unchlorinated one.
gh3, which has completed several projects in Edmonton as part of
the city’s designexcellence program, turned to Polyplan, naturalpool
PHOTOGRAPHY: COURTESY GH3 ARCHITECTURE, RAYMOND CHOW specialists based in Germany, for help devising the treatment and
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