Background/Objectives

The water sector needs to develop long-term strategies for deeply uncertain futures. With increasing awareness of the profound impacts of climate change on the water cycle, the industry is grappling with how to embed adaption and resilience into planning and decision making. A complicating issue is that when planning over 30, 50 or even 100 years into the future other drivers of change and uncertainty need to be considered – growth, urban densification, societal perspectives and behaviour change, political views and regulatory change, and technology change. The industry is not just needing to adapt to climate change but must make decisions for the century under ‘deep uncertainty’.

Approach/Activities

Adaptive Pathways Planning (APP) is emerging as a leading practice framework and approach for the water sector to use to develop long-term strategies and plans that explicitly respond to future climate change and other drivers of uncertainty. In the past 5 years the approach has been adopted widely in the Australian and New Zealand water sector, marking a shift from research and applications in coastal adaptation and flood mitigation (e.g., Thames Estuary 2100 Flood Management Plan and the Netherlands National Programme for Water Supply and Flood Management) to a much broader application in urban water management.

The approach involves a broad exploration of plausible futures and seeks to understand the issues, impacts and decision points for those futures. Options are developed and combined into sequenced pathways through time, with specified triggers for decision making and action. It is decision-based planning and results in a ‘living’ strategy or plan with a monitoring framework to enable actions to be brought forward or back in time, or a decision made to change pathway, as the future unfolds.

This has the potential to be a transformative approach for water security planning which is subject to high levels of uncertainty for both future supply and demand, as well as external political influences and fragmented governance structures. Many cities around the world are traditionally reliant on surface and groundwater resources and are facing a transition to alternative approaches to water management such as manufactured water sources and water conservation and efficiency as part of a broader One Water paradigm. This often means shifting from once-in-a-generation supply investments to an ongoing, strategic program of investments and water management decisions. Climate change is fundamentally changing our understanding of event probability and the utility of using historical data to inform decision making, requiring a redesign of our decision frameworks.

Results/Lessons Learned

This presentation will draw on case studies from major Australian cities including Melbourne, Sydney and Perth, covering the following topics: (1) shifting away from dam storage triggers to longer term risk based triggers (2) competition between seawater desalination and potable wastewater reuse (3) trade-offs between supplying hydrogen projects with recycled water and future potable wastewater reuse (4) role of integrated water management and water efficiency in deferring major supply augmentations (5) addressing the gap between regulations, guidelines and latest science, and (6) policy changes to allocate water for indigenous and environmental use. We will discuss the technical and governance considerations of each issue and lessons learned.