Tonsley Central Forest

At Tonsley Park in Adelaide and at the Kingston Foreshore in the ACT James Hayter of landscape architecture and urban design practice Oxigen shows the degree of transformation that is possible with a regenerative approach to contaminated sites.

Hayter’s landscape architecture and urban design practice is oriented around three key aspects: soil, water sensitive urban design and the history of landscape, including the Indigenous history and the way that Aboriginal culture works with the land.

James Hayter

“What I’m seeing in the way cities develop is an arrogance towards the land and how we treat the land, particularly with things like global warming,” Hayter told The Fifth Estate during a phone interview in the lead-up to the recent Forecast Festival of Landscape Architecture in Brisbane.

“We are encroaching on the land required for living things and agriculture.”

An example, he says, is the Adelaide suburb of Mt Barker, which has replaced a food-producing landscape with housing. This is not how we go about creating sustainable cities, Hayter says.

“When you think of all the great examples of cities in ancient civilisations, Macchu Piccu for example, the cities were formed in areas with rich soils around them, and the city provided water to those soils to grow food for the city.”

Two of the practice’s projects demonstrate an alternative to our cities sprawling across the food bowls, with dynamic places developed on contaminated former industrial sites.

The Tonsely development on the former Mitsubishi factory site is an urban renewal precinct being driven by the South Australian state government.

“Tonsely is the third iteration of the site,” Hayter says. “Historically, it was [initially] a site for agriculture, and the first cultivars of fruit trees in Australia were grown there. It was also a site for agricultural manufacturing industries, and a new plough and a new kind of harvesting machinery were both developed and manufactured there.

“Then it became the Chrysler plant, and then after Chrysler, Mitsubishi.”

The 11 hectare site is one enormous steel shed, with what Hayter describes as “reasonably contaminated” soil. Instead of pulling the shed down and starting from scratch, the SA government has specified a redevelopment that retains as much of the original structure and materials as possible in the interests of sustainability.

The firm has designed four urban forests that will grow inside the space, which is retaining the original roof trusses throughout. Re-roofing will not be carried out over the forested sections, which will be open to the elements allowing wind, rain and sunlight to enter.

Hayter says the forests will grow high enough to reach above the roof, providing a degree of shade to retained roof areas and reducing the sun’s thermal load on the roof. They will also cool the air within the space, and provide naturally shaded green spaces with walkways connecting them to other parts of the precinct.

The built element of the 20-year plans for redevelopment comprises a mix of educational, residential, retail, hospitality and commercial spaces, with a focus on incubator spaces for new businesses including high-value manufacturing, tech start ups and design firms.

Part of the government’s plan for the immediate future involves “pop up” events including markets and expos to bring the community into the space during these early stages.

Hayter said Tonsely will also be harvesting rainwater and stormwater for irrigation and to reduce potable water use, and will generate its own electricity with a major rooftop solar installation. Gardens around the sides will include edible gardens.

Water sensitive urban design and remediating the soil sufficiently to grow plants have been the two chief drivers for the landscape design.

“We are creating a paradise garden inside a post-industrial site,” he said.

“This is a great resolution out of what could have been a very mundane project, where they knock everything down and start again, which could also have used four to five times as much in the way of materials.”

Another of the recent regenerative landscape projects was the Kingston Foreshore in the ACT. Formerly the site for the ACT coal-fired power station, which left a legacy of fly ash and other contaminants, the site was also thoroughly contaminated with asbestos from the use of demolished fibro demountable housing as landfill after the power station was decomissioned.

Kingston Foreshore

Due to the level of contamination, which Hayter says was so bad “you couldn’t stick a shovel in the ground without turning up asbestos”, and the magnitude of the challenge of full remediation, the decision was made to cap and seal the landfill and create new soil and a landscape on top.

“It’s been a fantastic project. We are working with soil that isn’t the best, but it can still sustain plants, and it has been a creative challenge working out ways to construct the landscape without danger,” Hayter says.

A major priority was also ensuring the water quality of Lake Burley Griffin, which acts as a massive stormwater detention pond, is protected.

“We have been using sustainable materials, such as the 400-metre boardwalk, which has been constructed out of recycled 80-year timbers. We used a lot of unfinished materials, instead of [things like] stainless steel, which is a high embodied-energy material.”

One of the more unusual features of the Foreshore is it is one of the few cafe precincts that provides kayak parking. Kayaking on the lake is extremely popular, and the design incorporates open kayak decks that sit below the waterline at the edge of the boardwalk, so people can take their kayaks onto them, step out, and walk up the steps of the boardwalk to get a coffee.

Hayter says that, overall, his profession needs to take a green infrastructure approach to urban development.

“By taking that [approach] I mean thinking about waste, energy and healthy living. We should be working collectively towards a greater understanding of green infrastructure as part of our cities, and this needs to be accepted at all three levels of government,” he says.

“One of the futures of our professions is green infrastructure and embedding that in everything we do. We need to create collaborations with developers, all the engineering professions, architects, the real estate agents and so on, and work towards more common aims.”

Hayter says the South Australian government has itself approved the green infrastructure approach to urban development. The concept of the importance of nature’s “goods and services” including water, vegetation, air quality, shade, soil and amenity values has been embedded into the new planning legislation that is part of the 30-year Adelaide Plan. The masterplanning for Tonsley is a good reflection of how this plays out in practice.

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