Sense and sensitivity
by Ruth Slavid
Victoria Park in Sydney intercepts and re-uses water. Photo ©: Max Creasy
Visitors to Ecobuild earlier this year were impressed, as is everybody who has heard him talk, by Tony Wong’s presentation about water-sensitive design in Australia and nearby countries. While this is a subject with which the UK is only just starting to get to grips, it is an area where Australia seems to be way ahead. The reason is evident if you look at a Tedx talk that Wong gave in Canberra in May where he starts by outlining the scale of the problem that Australia faces.
A disastrous drought that lasted from 1997 to 2008 was followed by cataclysmic floods in January 2011. Their effects could have been even worse if the country hadn’t already started to adopt measures, pioneered in Melbourne, to make its cities water-sensitive. Wong had an important part to play in this. A civil engineer, his interest began in the early 1990s when he was looking at how biomimicry could be used to improve the quality of stormwater, and then realised that actually the problem was the behaviour of the stormwater itself.
A median wetland at Lynbrook Estate near Melbourne. - Photo ©: CRC for Water Sensitive Cities
From there he developed some projects that defined a new norm for working with water. And as if that were not enough, he now heads a research centre, called the Cooperative Research Centre for Water Sensitive Cities, based at Monash University in Melbourne. It has funds of A$120 million (around £75 million) and four research hubs in Brisbane, Melbourne, Perth and Singapore. Its aim is to bring together ‘the inter-disciplinary research expertise and thought-leadership to undertake research that will revolutionise water management in Australia and overseas’.
But although the ambition is large, the scale of the projects is not necessarily so. Wong, for example, has worked in Singapore as well as Australia and New Zealand (he has both run his own practice and, for a while, been part of AECOM). Singapore is a city-state with no hinterland and hence is obliged to work to create a densely populated but ecological and liveable environment. It is to be lauded for some of the ambitious schemes it has executed, such as Atelier Dreiseitl’s reworking of Bishan Park, where money has seemed to be, virtually, no object. But these are not the schemes that interest Wong. Instead he has concentrated on smaller-scale interventions. ‘My job,’ he said, ‘is to look at smaller, lower cost projects that can be implemented throughout the country without breaking the bank.’
Wong stresses that all his work has been in collaboration with landscape architects. ‘I couldn’t draw anything if my life depended on it,’ he says. ‘I have provided a very strong scientific layer to what is often a strong narrative about how landscape relates to the environment. My role is to provide a much stronger ecological meaning. How good it looks often is nothing to do with me.’
Photo ©: NCRC
The principles that he works to are becoming so universally accepted that it is difficult to remember that they were once revolutionary. But this acceptance certainly doesn’t mean that the job is done. There is still much to learn about the details of implementation, plus a new set of skills to diffuse.
An indication of this is that when Wong quotes projects, he often refers to some of the earliest ones, with which he was most closely involved. This is not as an ego trip but because, he says, when he paid close attention he could ensure that everything went according to plan. Projects that have followed have not always been 100% successful as not all of the approach has been understood. But Wong believes this is an unavoidable part of the learning process.
The principles are easily grasped however. Water is a precious resource, which is wasted when it runs off as stormwater. It takes nutrients with it that pollute water courses, yet treating it would be rohibitively expensive. The answer, of course, is to reduce the run-off, and to keep the water within the city as a resource not a problem – since the obverse of having too much water is not having enough. With the right engineering, many of the nutrients can be recovered within ecosystems, and the water can be re-used. ‘We should think of rain gardens as the kidneys of our cities,’ Wong says.
Photo ©: Neil Price
Once water has been filtered by natural processes, it is ready for a wide range of uses. ‘We should all have two taps in our houses,’ Wong says, ‘One for drinking water and one for other uses.’ Cities can be important water resources after a drought, Wong believes. In the countryside, if the ground is parched, any rain that does fall will be absorbed and not reach the water course. But in cities there will always be run-off. Capturing this and using it, at the time when it is most needed, is therefore essential.
Wong cites projects like Victoria Park in Sydney where he worked with landscape architect Hassell. Originally this area was part of a large wetland ecological system, and the current mixed-use design refers back to that period before the land’s long exploitation, first as a racecourse and then as heavy industry. The east-west streets have median wetlands (strips between the carriageways). Swales capture the first-flush water from the highways, and this water, which is filtered naturally, is then intercepted and re-used in water features.
An earlier pioneering project was the Lynbrook Estate, a housing development about 35km southeast of Melbourne. The initial stages of the scheme, which was not very successful, had a conventional stormwater drainage system. The Urban and Regional Land Corporation, which is the developer of the estate, then decided to use the later stages as a demonstration project for WSUDs.
Run-off from roads and streets is directed to grass swales and an underground gravel trench system that collects, filters and carries this water through a 150mm diameter perforated pipe to the main boulevard. This boulevard, which incorporates a gravel trench with another perforated pipe in it, acts as a stormwater retention system. Eventually, excess water from here runs into an ornamental lake from which water can, in turn, filter out to be used in irrigation. If this sounds a little mechanistic in principle, it is certainly not so
n practice. ‘It is a beautiful lush urban environment, with strong biodiversity,’ says Wong. It is this win-win – a more rational and frugal use of water along with the creation of more pleasant places to live – that encouraged the Victoria government (the state in which Melbourne is) to introduce legislation requiring all new major housing developments to incorporate water-sensitive design.
As a result, Wong became involved not only in designing projects, but also in capacity-building, to help other engineers develop the skills and knowledge necessary to implement such policies. Wong’s approach is, he says, ‘to work out some non-negotiables from the technical point of view and some of the things you do not need to get hung up on. Then you leave the door open for design creativity. It is unconventional for an engineer’s practice.’
Another project that is innovative is Waitangi Park in Wellington, New Zealand, for which the lead consultant was Wraight Athfield Landscape – a joint venture between Wraight +Associates and Athfield Architects. Built on a former industrial site, it could, says Wong, ‘so easily have been just another park.’ It is a park, but one that actually functions as part of the city’s water strategy, taking run-off from surrounding streets, harvesting it for irrigation and preventing pollution
of surrounding watercourses.
While Waitangi is on brownfield land, it is still a new piece of urban landscape. Evidently it is simpler to introduce these approaches with new construction, but, says Wong, ‘the focus is now on existing environments, on how we can capture the urban renewal process. A lot of cities in Australia are undergoing a period of densification. How can we start to embed a lot of green infrastructure in this process? How should we design buildings?’ Green walls, for instance can, he believes, be used to recycle and treat grey water.
As cities become denser, so having good quality urban spaces becomes more important. If those spaces can also work harder, attenuating stormwater run-off, harvesting water for re-use and providing a source of interesting planting to lift the spirits, we will all be much better off. While the principles of the approach are broadly understood, and Australia’s leading role is to be applauded, there is still plenty of research to be done. Wong’s research centre should have a long and fruitful existence.