Climate-Related Sea Level Rise and Coastal Wastewater Treatment Infrastructure Futures: Landscape Planning Scenarios for Negotiating Risks and Opportunities in Australian Urban Areas

Around the world, human populations and their supporting infrastructures are concentrated in coastal areas. With rising sea levels, these settlements and urban infrastructures are at risk of service interruptions, lasting damage and frequent climate-related hazards. Wastewater systems are especially vulnerable due to their proximity to coastlines. Despite the seriousness of sea-level-rise-induced challenges, a clear understanding of the risks and potential adaptations of coastal wastewater treatment systems and their associated landscapes in Australia has been overlooked. Further, there is a lack of urgency and awareness concerning this issue. In this study, we consider how scenario-based landscape design approaches might enhance current debates and approaches related to coastal change with particular reference to wastewater treatment systems and associated environmental landscapes. Adelaide is used as a case study, and a range of landscape planning exploratory scenarios are developed and evaluated to assess the possible consequences of different courses of action in uncertain contexts. We find that whilst wastewater treatment plants are threatened by climate-related hazards, there is an opportunity for landscape-scale environmental planning to manage risks and opportunities and improve ecological and economic outcomes. We also find that for wicked multidimensional problems, such as sea level rise, landscape scenario design testing can assist in identifying a number of creative adaptation approaches that are not immediately apparent. We find that approaches such as retreat, defense and accommodation are not mutually exclusive but can each share elements and strategies. The strategic potential of a more creative, scenario-based approach can therefore form a productive part of the sea level rise adaptation of coastal infrastructure landscapes in Australia and elsewhere.