Overview of 2025/26

The delivery program operated to the dry scenario (Seasonal Watering Plan 2025-26) during winter/spring and early summer/autumn to present. This was due to flow conditions reflecting rainfall and streamflow deficits accumulated from summer/autumn in the previous water year.

Dry conditions experienced in summer/autumn 2025 continued into winter and early spring. During winter, mean maximum temperatures were above average across the catchment, with rainfall and streamflow below average (Melbourne in Winter 2025).

Above-average monthly rainfall totals were accumulated at the end of October through November, leading to the spring season ending with above-average rainfall totals (Melbourne in Spring 2025). However, this masked underlying rainfall and streamflow deficits experienced throughout most of the season, which aligned with the dry operating scenario.

Environmental water delivered in 2025/26

302ML of water has recently been secured through trade in the Maribyrnong River in 2025/26. This water will be delivered as a series of freshening flows and baseflow supplementation during summer and autumn.

The first of 5 summer/autumn freshes is scheduled for February, with deliveries continuing through to May.

Lack of available environmental water constrained any opportunity to deliver flows during the winter/spring period.

Melbourne Water is working with DEECA and other stakeholders to try and secure an Environmental Water Entitlement for the Maribyrnong River through the Central Region Sustainable Water Strategy review process and other Integrated Water Management opportunities.

Key environmental values

In the Maribyrnong River system, water for the environment supports the following key environmental values.

Opportunities for shared benefits are also incorporated into planning and watering decisions, if they do not compromise environmental outcomes.

Potential watering actions

We plan for all climatic scenarios. Below are the proposed environmental watering actions for the Maribyrnong River (Mirrangbamurn) in 2026/27 under an ‘average’ year scenario (if water is available):

• Summer/Autumn freshes in reaches 6 and 7 (Jacksons Creek)