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project introduction

CASE STUDY # 9

Windsor St, Linear Parkland, Adelaide

location:Windsor Street, Unley (Adelaide) South Australia

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Ugly concrete drain gets a new lease of life

In an Adelaide inner suburb a lifeless concrete conduit has been transformed into a vibrant environmental trail.  Long and skinny, this green space snakes its way between suburban homes and the roadway.  Before its redevelopment, residents took the fastest route through the site with no reason to pause. Now they linger.

The impetus for change came as a result of frequent flooding of the drain, which created havoc on Windsor St and surrounding low lying properties. The City of Unley Council realised that the area needed a serious design rethink.  So they engaged Adelaide based landscape architect, James Hayter, to look at the problem.  Hayter came up with the idea of a main creek bed to carry most of the water volume, ephemeral creeks lines which only fill in winter, pathways, signage and loads of native vegetation.  The result, despite being just eight metres wide, is a newly greened space with wide benefits for the community, less insurance headaches and improved local ecology.  And the drain no longer floods!

Many of the plants were grown from seed, with an emphasis on local plants from the Adelaide Plains.  Over 20,000 plants have been planted.   As one way of addressing the loss of vegetation cover due to clearing in the urban area, rare plants are incorporated in the scheme, including the Garland Lily, Calostemma and the Native Lily, Bulbine.   The planting design includes a range of structural categories which increases its habitat value.  There are shrubs, trees, groundcovers, massed grasses and damp areas, logs, and stone walls with gaps for cover.  The planting diversity and small protective niches draws wildlife back into the suburbs. 

During their establishment, plants were watered with drip irrigation – necessary in a dry climate, like Adelaide’s.  After a two year establishment period, the irrigation was removed and the plants have continued to thrive.

The Windsor St linear trail is not an isolated green space. It stretches for a kilometre from the Fern Avenue Reserve in Malvern to the Henry Codd Reserve in Parkside.   The landscape architects aimed to link it to other green spaces, such as the Adelaide Hills, helping to form a continuous wildlife corridor through the urban area.

There are many positives about this project.  One of the highlights is the careful attention paid to sourcing landscape materials.  This is often an overlooked part of the landscape design-construction process.  At Windsor St, materials were carefully selected, from the reused stone walling to recycled sawdust for secondary paths. The reclaimed stone walls provide places for people to stop and rest in the sun, as well as basking spots for skinks. 

While the revamp, costing in the millions, might make some rate payers gasp, the overall benefits are huge.  Not only does a project like this signal that many planners are happy to regreen urban spaces and provide wildlife corridors, it also increases resident’s psychological and physical wellbeing and has an educative value.  Handsome metal signs explain the intent of the project. 

One sign uses a photograph from the 1980s showing Windsor St in flood with residents standing out in the street in shorts and bare feet.  Other signs explain the cultural and habitat significance of plants, like Grass Trees, and the significance of including rare plants in the scheme. 

One may ponder why creeks and wetlands were converted into concrete drains in the first place? 

This was a typical engineering response to divert water quickly away from infrastructure. Unfortunately it had seriously ecological consequences.   Not only did these actions result in a loss of ecological value but they adversely affected natural hydraulic systems.  The vegetation of creeks and drains and their catchments plays a role in filtering nutrients and sediments from reaching downstream water bodies, as well as slowing the passage of water in the catchment, reducing the potential of scouring and erosion.

In Canberra many natural drainage lines were converted to concrete drains during a period of engineering rationalism.  This old-fashioned approach is evident amongst many former drainage lines in the city and surrounds.  The Sullivan’s Creek Catchment in Canberra’s inner north is an example of a lengthy concrete drain.  It starts in the north, at the base of Mt Ainslie, traverses Hackett, past the Dickson playing fields, through O’Connor, to the ANU and eventually into Lake Burley Griffin.  It’s a stark scar on the landscape, devoid of life, except an occasional pool of water.  But few frogs spawn there.  After heavy rainfall events, which are predicted to occur more frequently with a warming climate, dangerously high water levels surge through the channel carrying plastic bags, debris, dog excrement and other pollutants. 

The creation of an off-line wetland at O’Connor, as water filtration for the City Edge development, adjacent to the Sullivan’s creek concrete drain has been an outstanding success. So successful, that an image of the wetland backed by townhouses graces front cover of the ACT government’s water sensitive urban design guidelines.

The O’Connor wetland is an excellent starting point.  However, the remainder of the catchment, except within the Australian National University, possesses little to entice people to stop, and enjoy the beauty and wonder of nature.  The current walking and bicycle path is a functional trail that connects people from a to b.  The landscape is a mix of homogenous dryland grass and trees chosen for their ornamental values. 

Prior to European settlement, the drainage pattern in the ACT was characterised by chain-of-ponds wetlands, likened to beads on a necklace.  In keeping with this natural pattern, the existing concrete drain could be converted into a series of wetlands linked by ephemeral drainage lines.  A diverse set of species would be planted including wetland plants, native grasslands (grasses, lilies, orchids and peas) and woodland plants.  Woodland trees like the Allocasuarina would provide a food source for the uncommon Glossy Black Cockatoo and provide a corridor to Black Mountain.  The return of frogs, and invertebrates, like dragon flies, would signal the environmental success of the development.

This linear parkland would be an environmental showcase for the inner north, drawing people from their houses to engage with the landscape.  If well designed and managed, it would engage residents as local stewards, taking part in weed removal, replanting of local native plants and deterring vandalism and anti-social behaviour.  It would greatly add to the social capital of the inner north neighbourhood. 

Within walking distance of the proposed parkland are five primary schools, two high schools and Dickson College.  This proximity to educational institutions provides an opportunity to engage the schools in the development of the landscape.  Like Windsor St, the opportunity exists for interpretive signage, but more importantly to harness the close physical relationship between the schools and the linear parkland as an environmental learning resource. 


Linear Parkland Fact Sheet

 



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