Water Think Tank
What is the Water Think Tank?
The Water Think Tank (WTT) is a vibrant network of individuals from the Maribyrnong catchment dedicated to enhancing understanding and advocacy for sustainable water and waterway management. Founded in response to low levels of local water literacy the Think Tank equips members with the knowledge to contribute informed opinions during government consultations and advocate for long-term water health.
With a focus on the Maribyrnong River and its creeks, the Think Tank addresses critical issues such as stormwater, drinking water, wastewater, and groundwater management. Since its establishment in 2023, it has run over 15 sessions, and engaged diverse representation from Landcare and Friends groups, through educational sessions with water industry experts and local government representatives.
As the region faces increasing population pressures and declining rainfall, the Water Think Tank fosters water-literate communities, empowering locals to participate in meaningful dialogue and drive sustainable, community-supported decisions for the future of the Maribyrnong catchment.
Stormwater and Integrated Water Management
This Water Think Tank session brought together Macedon Ranges Shire Council, Melbourne Water, and E2Design Lab to explore different perspectives on stormwater and Integrated Water Management (IWM). The discussion highlighted the need for collaborative planning to manage water sustainably, enhance urban resilience, and protect our waterways. From local government strategies to innovative design solutions, the session emphasised the importance of cross-sector approaches in addressing water challenges in the Maribyrnong catchment. To see the E2Design Lab presentation follow this link. To view Melbourne Water’s presentation follow this link. And to view the Macedon Shire presentation follow this link.
Creek Stories
The health of our local creeks reflects how much we value the places we call home. In this session, we heard from locals about their deep connections to these waterways—the stories of creeks and the people working to protect them.
For more information about our creeks and the people who care for them, visit: Creek Stories
Garden Hut Reservoir
This session took place on private property in Newham, adjacent to Garden Hut Reservoir, where decades of regeneration have created a thriving refuge for over 100 bird species and diverse aquatic life as featured in the property owner’s presentation. The visit underscored the complex challenges facing our waterways, with Greater Western Water’s presentation highlighting the pressures of climate change, urbanisation, and declining rainfall.
Garden Hut Reservoir, a key but low-cost drinking water source for Lancefield, undergoes year-round extractions, raising concerns among Water Think Tank participants about its impact on local ecosystems and long-term sustainability. The discussion reinforced the urgent need for bold government leadership and proactive community action to protect our rivers and creeks.
The Impact of Farm Dams on Waterways
This Water Think Tank session examined the growing impact of farm dams on water availability and ecosystem health, drawing on insights from the Moorabool catchment. Across Victoria, unregulated and expanding private dams are intercepting significant volumes of runoff, diverting water away from creeks and rivers, and exacerbating flow stress. This has profound implications for water security, aquatic biodiversity, and downstream users who rely on regulated access. Participants discussed the urgent need for stronger monitoring, compliance, and policy reform to ensure sustainable water management. This presentation is available upon request.
Environmental Water in the Maribyrnong Catchment
Environmental water is water that is set aside to support the health of rivers by sustaining aquatic habitats biodiversity, and water quality. In this session, Melbourne Water provided an in-depth definition of environmental water and looked at the policy and processes involved in securing environmental water in the Maribyrnong catchment. The session provided an update on the FLOWS assessment currently underway for the River. The discussion highlighted the challenges of balancing water allocations with ecological needs and the importance of securing flows to sustain the river’s health.
This session sparked a commitment from the Maribyrnong River and Waterways Association to develop a position statement on environmental flows, reinforcing the need for stronger advocacy and community engagement to ensure our waterways receive ‘ a fair share of the flow’ – the water they need to thrive.
Workshop: Mapping Our Water Future
In this session, we reflected on the journey so far, drawing on insights from our ten past sessions (see presentation here) to highlight what has truly resonated with our community. Our conversation was structured around three key themes:
1. The Journey So Far
We began by reviewing the standout moments from our previous sessions, pinpointing lessons learned, and recognising the evolving challenges in water management.
2. Identifying the Issues That Matter
Participants engaged in a thorough discussion on which water issues are most critical for our communities, the water industry, and the creeks themselves. From this we developed the Water Think Tank Prospectus, which outlines six opportunities to be further developed into practical projects:
- Cool Clear Water: Revitalise the community’s connection to local creeks through fun, safe, and celebratory events, including initiatives like testing treated water for recreational use.
- Water Fit for a Creek: Explore what a creek needs in terms of flow and water quality, integrating scientific insights with local land management practices.
- Reimagining Murnong Creek: Transform neglected urban waterways, such as in Riddells Creek, by engaging community members and experts to re-envisage and restore these spaces.
- Save Water, Save Your Money?: Examine how smarter water use can deliver both environmental benefits and financial savings, drawing on international examples and local experiences.
- The River Festivals of the Maribyrnong: Celebrate the diverse identities of the Maribyrnong River through multiple local festivals that combine community enjoyment with educational initiatives.
- The Wild World of Creeks: Foster a cultural exchange between urban and rural communities via field days, building stronger bonds and collaborative approaches to managing water challenges.
This session not only celebrated our collective learning but also set a clear roadmap for future engagement and advocacy, ensuring that our efforts in water management are grounded in community insight and industry collaboration.
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Maribyrnong River and Waterways Association’s Position Statement on Environmental Flows in the Maribyrnong Catchment
In this presentation MRWA reviewed their Position Statement on Environmental Flows in the Maribyrnong Catchment, emphasising the catchment’s crucial role in supporting biodiversity, water security, and climate resilience amid mounting pressures from reduced flows, groundwater extraction, and unsustainable water allocation.
The position statement includes 12 recommendations, an overhaul of water management practices—from returning portions of bulk entitlements and implementing robust stream flow and passing flow management plans, to regulating private water use and upgrading recycled water treatment—to secure a sustainable, resilient future for our waterways. MRWA’s position statement will be online soon.
Maribyrnong Floods of 2022 – Community Response and Priorities for the Future.
At this Water Think Tank session, we heard from Madeleine Serle, President of the Maribyrnong Community Recovery Association (MCRA), about the October 2022 floods and the extraordinary community-led response that followed.
Madeleine shared how, in the absence of perceived meaningful government action, local residents mobilised to form MCRA, now a nationally recognised voice advocating for flood mitigation, emergency management, and insurance reform.
The session explored how MCRA has kept the issue of flooding in the lower Maribyrnong front and centre through direct advocacy, technical proposals, and relentless community engagement.
Participants were inspired by MCRA’s energy, strategic focus, and refusal to let the devastation of 2022 be forgotten. The session highlighted the power of community organising in holding agencies to account and shaping the future of floodplain management.
Water Think Tank Recap: Exploring Options for Recycled Water from Sunbury
At this session, the Manager of Resource Planning at Greater Western Water, joined us to unpack future options for recycled water from the Sunbury treatment plant. GWW’s current plan is to divert excess water away from Jackson’s Creek, already under environmental stress, and pipe it to the Melton irrigation district and eventually the Western Treatment Plant in Werribee. But could there be a better option?
Greater Western Water walked us through an emerging conversation: treating Sunbury’s recycled water to a higher standard, one that meets EPA and DEECA guidelines for environmental flows. We explored what investment would be required, how this option stacks up financially and ecologically against transporting water off-site.
Understanding the Maribyrnong Catchment’s Climate Future
Geoff Steendam from DEECA provided an in-depth look at climate change and its implications for rainfall, streamflow, and water availability in the Maribyrnong catchment. His presentation synthesised the latest science on how climate drivers are shifting and what this means for our waterways.
Key takeaways included:
A clear trend of declining cool season rainfall and increasing temperatures, leading to reduced runoff.
Streamflow in Jacksons Creek, in particular, has shown significant declines over time, with changing rainfall-runoff relationships that date back to the Millennium Drought.
Projections point to a hotter, drier future—with less overall streamflow, punctuated by more extreme rainfall events.
These changes have significant implications for both water availability and flood risk planning.
Water Think Tank Recap – Recycled Water for the Environment
At our June Water Think Tank session, we focused on finalising the MRWA and Water Think Tank response to Greater Western Water’s proposal to release highly treated recycled water into Jacksons Creek. The group critically reviewed the draft submission, weighing the ecological, cultural, and community implications of using wastewater for environmental flows.
We explored the benefits of climate-resilient flows and potential habitat creation, while also flagging key concerns. This discussion strengthened the submission, which advocates for precautionary conditions and transparent evaluation.
The full submission can be viewed here.
Stormwater, environmental flows and Jacksons Creek
Priya van Ryn from Melbourne Water introduced an innovative approach to using stormwater from new urban developments east of Sunbury as environmental flows for Jacksons Creek downstream. While the scale of growth along the Bulla–Lancefield Road is striking, Priya explained how Melbourne Water is working to maximise environmental benefit from runoff generated by these hard surfaces.
Stormwater from new developments is collected in drainage basins, sometimes functioning as artificial wetlands. Melbourne Water is now modelling whether this water could be piped to a central storage and released in a managed way to better mimic natural flows in Jacksons Creek, particularly during summer low-flow periods when ecological stress is highest.
Priya also unpacked how the benefits of improved environmental flows are valued. She showed that when communities are asked directly, they value the ecological benefits of healthier flow regimes at around three times more than the figure typically used in cost–benefit analysis, which is based on the cost of purchasing water from irrigators. This suggests that projects like this may deliver far greater benefits than current economic assessments recognise.
View the slides along with the report on the economic benefits method discussed.
Victorian Waterway Management Strategy
At the session, Kylie Swinder and Simone Wilkie from Department of Energy, Environment and Climate Action (DEECA) presented on the forthcoming Victorian Waterway Management Strategy (VWMS). They outlined the intent of the strategy, its role in setting statewide direction for waterway management, and how it is designed to guide priorities and investment across diverse catchments.
The presentation highlighted key shifts in the new VWMS, including a stronger focus on urban waterways, climate change adaptation, whole-of-system thinking, and embedding Traditional Owner leadership and aspirations earlier in planning processes. The session provided valuable context for how the strategy is being framed ahead of its release and helped inform Water Think Tank discussion on priorities, gaps, and questions to explore through MRWA’s forthcoming response.
PFAS and contaminants in waterways
Dr Bradley Clarke led a discussion on contaminants in our waterways, with a particular focus on PFAS, often described as “forever chemicals”. Bradley explained how these substances persist in the environment, bioaccumulate, and move through interconnected systems, from wastewater treatment plants into biosolids, farmland, groundwater and ultimately rivers. The potential human and ecological health impacts of this widespread exposure were sobering.
Two key messages stood out. First, Bradley was clear that the use of wastewater sludge as agricultural fertiliser poses unacceptable risks where industrial waste streams contain PFAS and other contaminants. Second, he emphasised the importance of at-source treatment for industrial wastewater, arguing that preventing contamination before it enters the municipal system is far preferable to managing impacts downstream. While this raises challenging questions about cost and responsibility, the alternative is to continue shifting environmental and health burdens onto communities and ecosystems.
Project Update – Water Risks in the Upper Moorabool and Upper Maribrynong Catchment
At our final Water Think Tank session of the year in Sunbury, we heard from Matthew Hudson from Southern Rural Water, who presented findings from the Water Risks in the Upper Moorabool and Maribyrnong Catchments study. Matthew explored how farm dam development and domestic and stock water use are shaping water security and ecological health across the upper Maribyrnong catchment.
While the number of rural farm dams has increased only modestly (around 2%) between 2009 and 2025, the modelling shows a much larger change in total storage capacity, which has grown by around 16%. This increase is largely driven by the expansion of existing dams rather than the construction of new ones, meaning dams are holding significantly more water overall. The cumulative effect is a greater interception of runoff, with disproportionate impacts on streamflows during low-flow periods.
The session highlighted how these impacts are likely to intensify under climate change and reinforced the need for stronger, catchment-wide approaches to dam management that balance agricultural use with downstream environmental flows. The discussion underscored the value of evidence-based planning and transparent governance in protecting long-term waterway health across the Maribyrnong catchment.
All information about the project can be found at this Southern Rural Water webpage. The Discussion Paper provides an overview of the study findings.
Jacksons Creek condition and the potential for recycled water environmental flows
Dr Claudette Kellar and Dr Sara Long from RMIT presented findings from the Greater Western Water commissioned Jacksons Creek Ecotoxicology Study, which assessed the condition of the creek and the potential use of recycled water from the Sunbury Recycled Water Plant to support environmental flows.
The study examined water quality, contaminants, toxicity and aquatic ecosystem health across multiple sites in the catchment. Results indicate that while Jacksons Creek shows signs of ecological stress from a range of catchment-wide pressures including reduced flows, habitat modification and diffuse pollution, the recycled water discharge itself does not appear to be causing significant additional harm to aquatic biota when compared with upstream conditions.
Importantly, the preliminary findings suggest that, if carefully managed, recycled water could provide a safe and valuable source of environmental flows, particularly during dry periods when natural flows are low. The presentation reinforced the need for integrated, catchment-scale solutions and ongoing monitoring to support creek health while responding to growing water pressures. The presentation can be found here.
Thank you to our Water Think Tank community
Thank you to everyone who has participated in and presented at the Water Think Tank.
Your time, expertise, curiosity and willingness to share knowledge have played a vital role in strengthening water literacy across the Maribyrnong River community.
