Flows in the upper Barwon River are regulated by the operation of the West Barwon Reservoir. Water can be released directly from the reservoir into the west branch, or into the east branch via a diversion tunnel. The junction of the two branches is near Boundary Creek. Downstream of the reservoir, operational water can be diverted into the Wurdee Boluc inlet channel, a 57-km, concrete-lined channel that transfers water to Wurdee Boluc Reservoir.
Barwon Water releases passing flows in the order of 1-5 ML per day in both the upper east and west branch from the West Barwon Reservoir. These releases may increase to 15 ML per day in September in a wet year. Flood spills from the reservoir and natural inflows from unregulated and partly regulated tributaries add to the passing flows.
The Upper Barwon River Environmental Entitlement 2018 enables water to be made available for the environment from the West Barwon Reservoir. The entitlement provides an average of 1,000 ML per year and up to 2,000 ML of the total storage capacity at full supply. Water for the environment was first delivered to the upper Barwon in 2018-19. The current entitlement provides only enough water to meet the highest ecological objectives in the upper Barwon east branch (reach 4) and the upper Barwon west branch (reach 3) under particular climatic conditions.