Rethinking environmental water performance reporting: a Murray Darling Basin example

Summary

Traditional environmental water reporting often relies on binary pass/fail assessments, which limits its value for real-time decision-making. eFlow Projector replaces this rigid system with a nuanced, continuous assessment framework that demonstrates the value of partially successful flow events. This article explores how eFlow Projector could enhance annual planning and ecological accountability across the Murray Darling Basin.

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8 min read

Author: Zach Marsh

Murray Darling Basin environmental watering performance

About 23% of the water assets in the Murray Darling Basin are assigned for use in meeting environmental outcomes. This is a huge public asset, with annual delivery managed through sophisticated planning and delivery processes focused on environmental priorities and annual water availability. However, performance reporting remains opaque, particularly in evaluating the effectiveness of annual environmental watering actions and the longer-term performance of the Basin Plan.

The core issue is that there is a mismatch between long-term flow planning metrics and operational reporting needs.

Bridging the gap between planning and reporting

Environmental Water Requirements (EWRs) are typically defined in Water Resource Plans as multi-parameter flow events—covering magnitude, duration, timing, frequency, and independence—framed for decadal evaluation (e.g., “3 events in 10 years”). While this supports the design of environmental watering regimes and the comparison of modelled scenarios, it falls short for:

Annual planning
In-season tracking
End-of-year performance assessment

To bridge the gap, Truii has developed eFlow Projector, a data-driven web application that provides practical answers to essential operational questions. For example:

To what extent did we meet our environmental watering objectives this season?
Which EWRs were fully, partially, or not met at all?
How did performance vary across the landscape?
Which components of each flow rule (e.g., magnitude, duration, timing) contributed to the result?
How much did managed environmental water contribute to achieving each outcome?

Continuous scoring: moving beyond binary metrics

Traditionally, if an EWR failed to meet any of its parameters—e.g., magnitude slightly below target or timing off by one day—it was scored as a fail. However, ecological responses are rarely binary. Unlike traditional methods, eFlow Projector assesses flow targets on a continuous scale rather than a binary pass/fail. This means partial achievement—such as a slightly delayed event or lower-than-ideal magnitude—still contributes to the performance score, providing a more nuanced and ecologically realistic picture of what’s been delivered.

Murray Darling Basin example

To illustrate the continuous function/partial success approach in the Murray Darling Basin context, we have applied used eFlow Projector to create both a continuous scoring/partial success based scenario as well as a traditional binary approach scenario, and we apply both to 72 EWRs across 23 sites in the Basin as presented in Sheldon et al (2024).

Analysis set up

We have used the default partial success parameters for magnitude, duration, count and independence within the application, which have been developed through applying the Victorian Environmental Water Holder (VEWH) approach to planning several hundred EWRs across Victoria, including many that lie within Murray Darling catchments. Additionally, we have added a shoulder month to the ideal seasonal timing, whereby if an EWR occurs one month either side of the ideal timing it is worth 50% of the value of an event that occurs within the ideal timing window.

Results

eFlow Projector allows the compilation of EWRs into a ‘compliance report’ to report the collective performance across many catchments and EWRs within each catchment. The dynamic compliance reports can be filtered by location, EWR type and EWR importance. The images below (figures 1 and 2) show a simple snapshot for a single year (2011-12) between the binary and partial success/continuous scoring approaches.

Figure 1: Binary assessment compliance report for 2011-12 – see interactive version

Figure 2: Partial success compliance report for 2011-2012 – see interactive version

The difference is clear, with three ‘successful’ (100% compliance) catchments and 20 failures for the binary approach. For the partial success, there are similarly three successful catchments, but the flow in 19 of the 20 ‘failed’ catchments provided some contribution toward the EWRs.

Perhaps the most telling way to compare the approaches is a side-by-side animation of the annual results.

Figure 3: Binary vs partial reporting through time.

eFlow Projector allows compliance reports to be shared. Select one of the following links to view the shared reports for the success of the same EWRs using the different scoring approaches:

Additional features that give eFlow Projector an advantage over traditional reporting methods

In addition to the spatial and temporal exploration of the performance of catchments and individual environmental water requirements, there are additional features in eFlow Projector, not demonstrated in the example above.

Prevailing climate

eFlow Projector further supports operationalising environmental water reporting by allowing the consideration of prevailing climate. This allows different flow requirements to be met depending on the prevailing climate. Are we trying to enhance reproductive opportunities during average and wet years, or trying to keep things alive during droughts? This concept is well used by the VEWH who define environmental watering requirements in their annual watering plan in terms of the prevailing climatic conditions.

Attribution of water contribution

The purpose of held environmental water is to supplement river flows to achieve desired environmental outcomes. eFlow Projector can account for contributed environmental water and report which watering requirements were supplemented (and by how much) due to the judicious use of held environmental water (as opposed to natural flow).

Importance of EWRs

Not all flow rules are equally important, nor do they always require reporting. In this case eFlow Projector includes four reporting tiers to allow subsequent filtering to focus on just the high priority environmental watering requirements.

Using eFlow Projector in the Murray Darling Basin will support more effective environmental water management

Long-term flow planning metrics are not sufficient for operationalising and reporting environmental outcomes. eFlow Projector brings ecological nuance, operational relevance, and transparency to the forefront of environmental water management. As the Basin Plan enters its next phase, tools like this are essential for making our environmental water investment more accountable, understandable, and ultimately more effective.

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