The Moorabool River is a highly regulated river that, despite substantial extraction and many years of drought, still retains significant environmental values. It flows southward from the Central Highlands between Ballarat and Ballan to join the Barwon River at Fyansford. The catchment is heavily farmed with about three-quarters of the catchment area used for agriculture.
Water allocated to the Moorabool River environmental entitlement is stored in Lal Lal Reservoir and includes passing flows that help maintain flows in the river. The Moorabool is also a water supply catchment for Barwon Water with releases from Lal Lal Reservoir being diverted for urban water supply at She Oaks Weir. These releases contribute to environmental outcomes in reach 3a and 3b and allow more efficient delivery of environmental water to reach 4. Barwon Water and Corangamite CMA work together to maximise these benefits.
There are several large water storages in the upper reaches of the river (including Lal Lal Reservoir). In the lower reach (between She Oaks and Batesford) there are nine private diversion weirs that are a significant barrier to fish. These barriers have increased the extent of slow-flowing habitat and reduced habitat diversity in the lower reach of the Moorabool, reducing the diversity and abundance of migratory fish in this part of the river.
Environmental water can be used to manage flows in reaches 3a, 3b and 4. The priority reaches for environmental water delivery are the reaches between Lal Lal Reservoir and She Oaks Weir (reaches 3a and 3b, as shown on the map), as these are where the small amount of available environmental water can have the most beneficial impact. Environmental water delivered also provides benefits to significant flow-dependant values in reach 4, which flows from She Oaks Weir, Meredith down to the confluence with the Barwon River in Geelong (see system map below).