By Professor Ali Cheshmehzangi
Head of the School of Architecture, Design and Planning, The University of Queensland
Australian cities are investing more than ever in nature‑based solutions, yet outcomes will remain poor while water and parks are treated as an environmental layer rather than core urban systems.
Although Australia's cities have adopted the vocabulary of "blue" and "green" infrastructure, delivery is still unequal, dispersed, and frequently symbolic. The underlying systems that link water, ecology, and urban form are rarely planned or regulated as integrated assets, despite the addition of parks, the rehabilitation of waterways, and the announcement of tree-planting goals. As a result, the gap between declared sustainability goals and quantifiable urban performance is widening.
The core issue is a lack of system thinking, not a shortage of initiatives. Rather than being considered essential urban infrastructure, blue and green infrastructure is still viewed as an ‘environmental layer’. Instead of structuring development frameworks, water-sensitive design, urban forests, wetlands, and coastal systems are much too frequently added to them. This restricts their ability to deal with the issues that are most important in Australian cities: unequal access to high-quality public space, heat stress, flood danger, and biodiversity loss.
This conflict is reflected in the discussion of "nature in cities", a very important topic that we have recently covered in three comprehensive edited books. Green views, lifestyle value, and urban branding are some of the ways that nature is framed as an amenity. On the other hand, it is positioned as a performative system that supports public health, restores ecological function, controls runoff, and cools microclimates. Although the policy text often tries to incorporate both, the former is typically used in implementation. "Green" runs the risk of being more aesthetically pleasing than useful if performance standards are unclear.
Regulatory settings reinforce this problem. State-by-state planning processes recognise the value of blue/green infrastructure, but development-level regulations are frequently negotiated, advisory, or inconsistent. Landscape planning, biodiversity conservation, and water management are all regulated by different laws with little overlap. Particularly at the interfaces of municipal, state, and catchment-scale responsibilities, this fragmentation results in deficiencies in some areas and duplication in others.
Two of the most urgent issues facing cities like Brisbane, Sydney, and Melbourne are urban floods and heat mitigation. Rain gardens, street trees, and permeable pavements are examples of localised interventions that are becoming more prevalent, but their overall influence is limited by a lack of cooperation at scale. Urban design outputs do not always incorporate catchment dynamics, upstream-downstream linkages, and long-term land-use decisions. Because it is not governed as a system, the system operates below its capability.
A more disciplined approach would start with reframing blue and green infrastructure as essential, performance-based urban systems. This necessitates going beyond inputs, like tree canopy percentages or open space ratios, in favour of quantifiable and enforceable results. Planning regulations should be based on equitable access measures, biodiversity connection indices, urban cooling thresholds, and stormwater retention targets rather than additional rules.
Second, governance systems must be consistent across sectors and scales. To lessen fragmentation, integrated planning tools that connect water, land use, and ecological systems are required. This calls for shared accountability; it's not just a coordination exercise. Blue and green infrastructure can be provided as a shared obligation rather than an optional add-on thanks to cross-agency requirements, cooperative funding methods, and uniform reporting standards.
Third, cumulative impact needs to be considered in regulatory frameworks. Even though individual advancements might satisfy compliance standards, they might not produce system-level results when taken as a whole. Ecological continuity, urban heat, and hydrological performance should all be assessed strategically at the precinct and urban levels. In the absence of this, cities will continue to face increased risk even as investment rises.
Fourth, the logic behind investments needs to be adjusted. In cost-benefit analyses, blue and green infrastructure is still underappreciated, especially when benefits are spread across the social, environmental, and health domains. These co-benefits should be acknowledged by infrastructure funding models, which should encourage long-term asset management in addition to initial capital delivery. The manner that urban woods, wetlands, and rivers are prioritised and funded would change if they were treated as depreciable, maintainable assets.
Lastly, the shortcomings of the existing models of urban expansion must be addressed. Without integrated green and blue systems, densification runs the danger of increasing runoff, heat, and spatial disparities. On the other hand, low-density growth frequently deteriorates ecological systems on the outskirts of cities. The question is not whether or not cities should expand, but rather how that expansion might be planned around environmental systems rather than forced onto them.
Australia can take the lead in this area because of its policy frameworks, technical know-how, and environmental urgency. Clarity in purpose and consistency in application are lacking. Urban development must adopt blue and green infrastructure as its organising principle; it cannot continue to be a parallel priority. Integrating water and environment into urban systems is essential if the goal is to create liveable, productive, and climate-resilient cities. It is the prerequisite for future urban performance.
