The Ovens system rises in the Great Dividing Range near Mount Hotham and flows about 150 km to join the River Murray in the backwaters of Lake Mulwala. Two small water storages have been constructed in the system: Lake Buffalo on the Buffalo River and Lake William Hovell on the King River. The regulated reaches of the Ovens system include the Buffalo River downstream of Lake Buffalo, the King River downstream of Lake William Hovell and the Ovens River from its confluence with the Buffalo River to the River Murray.
The Ovens system maintains a larger proportion of its natural flow regime (particularly in winter/spring) than do other regulated rivers. This is a result of relatively small storages that spill regularly and allow unregulated flows to the rivers.
The water that flows out of the Ovens River is regulated by the largest weir pool (Lake Mulwala) on the Murray regulated system. Ovens River flows contribute to the reliability and variability of the flow regime for the River Murray and support many downstream uses including irrigation, urban supply and watering of iconic sites (such as Barmah Forest).
Environmental water is held in Lake Buffalo and in Lake William Hovell and can be released under regulated conditions when the storages are not spilling. Five reaches in the Ovens system can benefit from environmental water releases. While all are important, there are relatively small environmental holdings available in the system to meet the needs of all reaches. The volume available is well short of the volume required to meet the flow objectives, but it is still delivered in the most beneficial way possible. When water is only available from the holdings, outcomes in the reaches immediately downstream of the storages are targeted. When paired with consumptive water on its way to the Murray system, additional environmental benefits are likely to be achieved in the lower Ovens River.