Barwon Water releases passing flows in the order of 1–5 ML per day (and up to 15 ML per day in September during a wet year) from the West Barwon Reservoir into the West Barwon River. Flood spills from the reservoir and natural inflows from unregulated and partly regulated tributaries add to the passing flows.
A new entitlement was established in April 2018, enabling water for the environment to be used in the upper Barwon River for the first time in 2018–19. The entitlement provides 1,000 ML per year on average from the West Barwon Reservoir.
In light of this new entitlement, the Corangamite CMA updated the Upper Barwon, Yarowee and Leigh rivers environmental flows study in 2018–19, to ensure management decisions are underpinned by the best available science and information. The Environmental Flows Technical Panel included a representative of the Wadawurrung Traditional Owner group, to specifically consider the Aboriginal values of the waterways in their region.