Securing a resilient water future for Greater Bunbury
At a glance
We supported Aqwest Bunbury Water (Aqwest) to update the Greater Bunbury Urban Water Strategy in response to faster than forecast water demand growth and increasing climate variability. Using adaptive and scenario-based planning, the strategy sets out a clear pathway for future supply decisions. It supports reliable water services and long-term resilience for the Greater Bunbury community.
The challenge
Aqwest supplies drinking water to approximately 18,000 properties across Greater Bunbury and relies on a licensed groundwater allocation of 7.6 gigalitres per year. Long-term planning indicated this allocation would meet demand until 2065.
In the 2023–24, water demand grew faster than forecast, exceeding the licensed allocation earlier than expected. Population growth, changing water use patterns and extended dry conditions increased pressure on groundwater resources.
Aqwest needed to understand the drivers behind this shift and establish a clear long-term planning pathway that can respond to uncertainty, meet regulatory requirements and maintain reliable water services for the community.
Our response
We worked closely with Aqwest to develop the Source Development Plan and update the Greater Bunbury Urban Water Strategy.
The process began with a collaborative workshop to identify the factors shaping future demand and water availability, including population growth, investment priorities, regulatory obligations, community expectations and climate variability. These insights informed the development of three planning scenarios to test performance under a range of plausible futures.
To strengthen demand forecasting, we combined 15-year population projections with climate modelling, ensuring future demand pathways reflect both demographic change and environmental variability, rather than relying on population growth alone.
We also assessed 15 potential water sources using a multi-criteria framework that considered economic, social, regulatory and technical factors. While groundwater remains the most accessible option in the short to medium term, the analysis showed it could not meet long-term demand on its own. We therefore explored alternative sources and efficiency measures, alongside actions to reduce system losses and support smarter water use across the community.
The impact
The updated Greater Bunbury Urban Water Strategy provides a clear 10‑year roadmap, supported by a longer‑term planning outlook. It identifies key decision points, investigations and internal milestones to guide future investment.
By incorporating climate variability as a core demand driver, the strategy supports Aqwest to act earlier and plan with greater confidence. It highlights the need to prepare for climate‑independent water sources and provides visibility of long lead times for future supply options.
The outcome is a more resilient planning framework that reduces reliance on groundwater alone, while supporting reliable water services that underpin housing, local businesses and community wellbeing across Greater Bunbury.