Water available under the Tarago environmental entitlement is stored in and released from Tarago Reservoir. This water is primarily used to meet environmental objectives in reach 2, which is between the reservoir and the confluence of the Tarago and Bunyip rivers, as Figure 3.3.1 shows. Water for the environment that is delivered to reach 2 also supports environmental flow recommendations in reach 6 (Bunyip Main Drain).
Year-round passing flows in the Bunyip and Tarago rivers are stipulated under both the environmental entitlement and Melbourne Water’s bulk entitlement. Downstream of Tarago Reservoir at Drouin West, this equates to the lesser of 12 ML per day or natural flows. The magnitude of these passing flows is generally sufficient to meet the minimum low-flow requirements in summer/autumn, but it is much less than the recommended minimum flows in winter/ spring; and it does not provide any of the freshes or higher flows that are needed throughout the year to support environmental outcomes.
Water releases to meet irrigation demands create variable flow patterns in the Tarago and Bunyip rivers throughout the year. The magnitude and timing of these releases can influence environmental outcomes, and Melbourne Water continues to work with Southern Rural Water to optimise the shared value derived from irrigation releases.