Interview: Tony Wong

Professor Tony Wong is Professor of Civil Engineering at Monash University and Chief Executive of the Cooperative Research Centre for Water Sensitive Cities (Australia and Singapore). Professor Wong is internationally recognized for his award-winning urban design projects, research and strategic advice in sustainable urban water management and water sensitive urban design. He has previously served on the Australian Prime Minister’s Science Engineering and Innovation Council’s ‘Water for Cities’, and has been cited as having defined "a new paradigm for design of urban environments that blends creativity with technical and scientific rigor”.

When and why did sustainable urban water management/WSUD/LID/SuDS come about?

Sustainable urban water management started from a perspective of environmental protection whether it be WSUD, LID or SUDS. There are subtle differences these three terms—WSUD focuses on integrative urban design in delivering sustainable urban water management for improved sustainability (and resilience) outcomes. In doing this, WSUD is less focused on the simple application of technology. In Australia, WSUD was first conceived as a new planning framework in the mid 1980s but didn’t get much traction (mainly, I believe, due to an inability of those who first developed the idea to articulate tangible outcomes that would meet the needs of the community and industry at that time). In the early 1990s, water quality protection of major rivers and bays that receive stormwater became an important focus. In Melbourne, where WSUD really took off in the early 1990s, the protection of Port Phillip Bay was a key concern of the state government (following the significant initiatives in the USA to protect Chesapeake Bay from stormwater pollution). It was around the same time that research activities undertaken by the CRC (Cooperative Research Centre) for Catchment Hydrology at Monash University started to address the role of constructed wetlands, and then in late 1990s, of biofilters in stormwater cleansing with these features being incorporated into urban landscapes. Concurrently, such stormwater Best Management Practices (BMPs) were also being investigated in the USA. They were subsequently integrated into urban development and coined LID where the focus on water infiltration and filtration were espoused. In the UK, infiltration was also extensively investigated and coined Sustainable Urban Drainage (SuDS).

What are WSUD’s key aims?

The key aims of WSUD are to manage urban water (whether stormwater or wastewater) in a manner that best recognises the resource potential of these different water streams, the potential for their impact in reducing the incidences and severity of floods, their potential to reduce the vulnerability of cities to drought and more recently the potential to recover resources from our sewerage, beyond water, e.g. energy and nutrients. The harnessing of these potentials is through good urban design and architecture (both building and landscape). We often use the notion that WSUD is the practice and Water Sensitive City (or precinct) is the outcome. WSUD is expressed in many different forms, from the green walls of buildings that also cleanse greywater while utilizing it as a water source for irrigating the green wall itself; to stormwater treatment along ecological landscapes that form part of the blue and green corridors of a city; the blue/green corridors being corridors for flood detention and safe passage; to the recycling of treated wastewater for non-drinking water uses such as toilet flushing; and to maintain green landscapes in cities while preserving higher quality water for drinking purposes. Ecological landscapes can promote multiple ecological and ecosystems benefits, create of sense of place and provide important amenity in cities. My key argument here is that spaces in the public domain are essential features of public amenities. However, these urban landscapes must be functional beyond providing spatial amenities. Our knowledge of the traditional ‘values’ of open spaces and landscape features needs to be bolstered with an understanding of the ‘ecological functioning’ of the urban landscapes that capture the essences of sustainable water management, microclimate influences, facilitation of carbon sinks and use for food production.

WSUD seems to facilitate the blending of vision and creative problem solving, technical and scientific rigor, and practical application and realization. What are the keys to this?

The city is a melting pot of many of the challenges we face today and there are many lenses through which different disciplines of practice can interpret resilience. In the contemporary urban water management perspective, resilience as a principle needs to encompass biophysical (anthropogenic and natural) and social/institutional resilience. Adaptability of infrastructure and institutions is fundamental. From an urban water management perspective, urban water systems need to have a level of robustness in their (combined biophysical and social) capacity to accommodate major system ‘disturbances’ (such as floods, droughts, heat waves and waterway health degradation) and the adaptive capacity to create opportunities from these disturbances for innovation and development or even the pursuit of new trajectories. Recent occurrences in the last decade of record breaking climatic events—whether it be floods or droughts or heat—have focused on the political language of resilience. The need for ensuring resilience has a higher level of urgency to communities and governments than what ‘sustainability’ was ever able to achieve in the last 20+ years since the Rio Summit. The reality of course is that we have reached this level of urgency as a result of not having been effective in mainstreaming sustainability in fostering economic development.

The key to success in blending vision and creative solutions is in fact in the practice of urban design—the practice of blending innovative solutions across multiple disciplines into the urban form. I have always been fascinated with the practice of urban design often led by architects and more recently landscape architects. I see engineers can play an important influencing role in this process, and the successful projects are usually those where the urban designers are inclusive and understand the interplay between technology, terrestrial and aquatic ecology, and the built form.

In our need to transition to a post-carbon era, why do governments utilize desalination plants over alternatives such as rainwater, stormwater and wastewater systems to provide a more sustainable water supply?

Many of the decisions to build desalination plants have been made in the midst of crisis. Desalinated water is a reliable source of water but the most expensive amongst all the possible sources of water—but it provides certainty and in a crisis, governments need the certainty of their decisions. Many of the more sustainable solutions require longer incubation in society because of the diffuse nature of their implementation. The fact that many of the desalination plants in Australia (with the exception of Perth) have come online at a period when dams are filling have certainly taken some of the shine off these projects. Nevertheless these facilities are of strategic importance to the water supply security of many of these cities—they provide an era of stability in terms of water supply security over the next 20 years or so in enabling a greater and more holistic development of water management strategy to secure the sustainability and resilience of these cities. It would be a grave mistake if cities chose not to invest in incubating more sustainable solutions just because they now have a desalination plant. Population growth, increasing water consumption and more severe droughts would mean that there will come a time when we will be faced with the need for building another desalination plant if we do not use the time we have now to develop and implement more sustainable solutions.

Is WSUD largely dependent on legislation mandating its implementation?

The adoption of a water sensitive approach to urban development and redevelopment needs to be supported by enabling legislation and regulation. This should include clear articulation of outcomes—but not prescription of the means towards achieving the outcomes. Outcomes stipulated could include (i) the quality of stormwater to be attained before its discharge to the receiving waters; (ii) the level of substitution of the traditional sources of drinking water with alternative water sources (stormwater and recycled wastewater for example) which may in some cases be treated to drinking water standards; (iii) the reduction in peak discharges for a range of flood scenarios; (iv) ecological values of urban streams; (v) the reduction in local temperature attributed to WSUD urban heat management just to name a few.

How reliant is WSUD on maintenance? Is this something that clients need to be willing to accept?

WSUD features in the public realm are green infrastructure—the operative word being infrastructure. These assets must be managed as community assets with clearly defined maintenance and operation provisions. We have to look beyond the public realm as simply a place that provides amenity and recreation for local communities. In fact, if we are to get really serious about green infrastructure, we need to clearly articulate from the outset what range of functions we expect from this infrastructure. The detention and safe passage of floodwaters, the cleansing and harvesting of stormwater, support for mitigating urban heat, productive landscapes and maintaining urban biodiversity are just a few of the functions that should be identified and clearly articulated from the beginning. And of equal—if not greater—importance, a whole of government approach combined with a more robust economic valuation framework is essential. With this in place, we can fully recognize all the economic and community benefits that can be achieved from green infrastructure. Then maybe we can say we’re really getting serious about green infrastructure.

Australia is increasingly implementing its ‘purple-pipe’ system for supply of recycled water. Are other regions following or leading the implementation of these types of systems?

Yes, the delivery of recycled water for non-drinking purpose is an important step in reducing our dependency exclusively on drinking water from the mains (eg. the traditional source of water) for all of our water usage. Many cities around the world are experiencing severe droughts at the moment—Sao Paulo, Bangkok just to name two current hot spots. However, many of these cities are still not looking at the total water cycle and therefore are missing out on realising the full potential that a water sensitive approach to urban water management can deliver. Furthermore, bringing in a ‘purple-pipe’ is a large scale operation taking many years to implement—and not necessarily one that offers a solution to an immediate drought crisis.