Queensland's Wivenhoe dam with floodgates open. Source: Fotolia. Copyright: daphot75

+ How can we know if replacement infrastructure will be more resilient than that which it replaces?

If infrastructure is to be truly sustainable, we need a way to understand what resilient infrastructure looks like, and we need a way to compare infrastructure designs and systems to achieve the most resilient outcome. Sustainability ratings tools have the potential to help us do this. 

In the wake of recent natural disasters like Hurricane Sandy and the Queensland floods, major infrastructure programmes are planned or are underway in several countries. But without properly understanding resilience, how can we know if this replacement infrastructure will be more resilient than that which it replaces? 

Infrastructure investment decisions have long-term consequences, as the assets can shape development for decades – often beyond their lifetime. So decisions on infrastructure should anticipate the long-term environment, needs and constraints under which it will function. 

However, our ability to predict the future has been shown to be limited. Climate change is introducing deep uncertainty that makes this even more difficult. The environmental conditions under which infrastructure performs are likely to change radically and its design needs to take this into account. 

Sustainability thinking is crucial for making clear the connections between the infrastructure project and the local and wider society, economy, environment and businesses. It is also vital to spotting where these connections could cause serious vulnerabilities that put the entire system at risk. Ensuring that these connections are elastic, adaptable and resilient will benefit society, the economy and the environment. 

So how do we understand what constitutes resilient infrastructure? How can we compare designs to see how they would contribute to a resilient system? Is there a role for infrastructure rating systems in improving our understanding? 

There are several infrastructure sustainability rating tools available: the Australian Green Infrastructure Council (AGIC)’s IS tool, the Institution of Civil Engineers’ CEEQUAL tool and the Institute of Sustainable Infrastructure’s ENVISION tool

Other infrastructure rating tools are in development elsewhere. And AGIC is in early discussions about establishing a ‘World Council of Sustainable Infrastructure’ to encourage the alignment of these different tools. 

Rating tools not only provide a way to determine an infrastructure asset's sustainability, they also enable comparison of the sustainability of different assets, or of different design solutions for a single asset. And while the principal use for these tools is to determine the asset's rating, they can also be used – informally – in 'design' mode. 

None of the tools listed above directly address asset resilience in their current formats but they give some indications. In design mode the performance of those characteristics that affect the resilience of the asset can be tested and the comparative resilience outcomes identified. We can then select a design with a reasonable knowledge of its resilience characteristics. 

For example, there are several infrastructure-asset rehabilitation programmes underway in various countries post recent natural disasters where it would be immensely beneficial to understand the resilience attributes of differing solutions.

Using ratings tools to understand resilience is an important area for the development of these infrastructure sustainability tools. Significant progress will be made in this direction over the next years, as ratings organisations and universities (University of Leeds Institute for Resilient Infrastructure for example) develop the means to measure infrastructure resilience. These will provide a positive statement about the advantages of sustainability thinking as applied to infrastructure.