Decision Dilemma in Adapting Stormwater Systems to Climate Change: A Tale of Three Cities

Abstract

Infrastructure assets require substantial capital investment to ensure long operational lifespans. This poses significant risk to local governments when considering that infrastructure is sensitive not only to the climate at the time of construction, but also to climate variations over their lifetime. The impacts of the 2011 Queensland flooding demonstrated the risks that infrastructure can face, and highlighted the economic and social damages associated with these types of events. Specific to this research, stormwater infrastructures are considered one of the most costly and vulnerable to a changing climate. It is therefore critical that stormwater systems can be adapted to withstand current as well as future impacts of natural hazards brought about by climate change. In light of this, this study focuses on identifying and evaluating a set of adaption alternatives to prepare stormwater systems for future climatic changes. To evaluate these alternatives, the authors adopt a Multiple-criteria Decision approach involving multiple stakeholders across three coastal cities in South East Queensland, Australia. A decision hierarchy was formed by consulting three stakeholder groups, which included professionals from engineering, finance and planning sectors of local government. Then, a goal, five criteria and five alternatives were determined. Data collected from the three stakeholder groups were analysed, and the preliminary results indicate that each stakeholder group identifies different priorities for each of the alternatives. The highest priority for the engineering and planning departments was to Modify Planning and Land Use Control Standards. However, the finance department identified that to Change the Stormwater Infrastructure Design Standards was the highest priority. Furthermore, it was observed that the priority values for the adaptation alternatives varied significantly depending on whether these were based on the combined judgements of all participants, or the judgements of the individual stakeholder groups and regional councils. This suggests that future decision makers need to structure a hierarchy model that restricts stakeholder groups to only making priority judgments with regard to themselves.