1.2 Unregulated river
Volume could not be quantified in a way that is complete, neutral and free from material error; therefore, it was not reported in the water accounting statements.
The following figure shows a map of regulated and unregulated rivers in the Melbourne region. The Yarra River and Bunyip River are unregulated rivers. The Maribyrnong River is regulated along Jacksons Creek downstream of Rosslyne Reservoir. Deep Creek is unregulated upstream of its confluence with the Maribyrnong River. The Werribee River is regulated downstream of the point where Pykes Creek Reservoir enters the river. Tributaries of the Werribee River, Lerderderg River, Pyrites Creek and Djerriwarrh Creek are all unregulated upstream of the storages.
Regulated and unregulated river channels in the Melbourne region
Water is diverted from regulated and unregulated river channels under licensed water access entitlements. Volumes diverted during 2010–11 are available under 17.7 Non-allocated diversions to users and 17.11 Surface water allocation diversion.
To estimate the volume of water stored in river channels a detailed understanding of channel widths and surveyed water level–depth relationships is required. While the stream gauge network throughout the region is adequate to monitor flows, it is not adequate to provide a reliable estimate of river channel volume, therefore these are unavailable. The volume of water stored in regulated channels at the start and end of the 2010–11 year is expected to be significant.