Skip to content
   
 

The Moorabool River is a tributary of the Barwon River. It flows south from the Central Highlands between Ballarat and Ballan to join the Barwon River at Fyansford just north of Geelong. The Moorabool River is a highly regulated catchment with major storages that include Lal Lal, Moorabool and Bostock reservoirs.

The lower section of the Moorabool River between She Oaks and Batesford has nine private diversion weirs that are significant barriers to fish. These barriers have increased the extent of slow-flowing habitat and reduced habitat diversity.

The Moorabool is a water supply catchment for Barwon Water and Central Highlands Water. Releases from Lal Lal Reservoir for urban water supply contribute to environmental outcomes in reach 3a and 3b (above Barwon Water’s diversion point at She Oaks) and allow more efficient delivery of water for the environment to reach 4. Barwon Water and Corangamite CMA coordinate to make releases in tandem, where possible, to optimise these benefits.

Water allocated to the Moorabool River environmental entitlement is stored in Lal Lal Reservoir. The entitlement includes passing flows that are a significant component of annual streamflows and help maintain low flows through winter. The priority reaches for deliveries of water for the environment are between Lal Lal Reservoir and She Oaks Weir (reaches 3a and 3b, as shown in the system map below), as that is where the small amount of available water can have the most benefit: water use is limited by both inflow to the reservoir and by a use cap specified in the entitlement. Environmental flows may also provide some benefits to flow-dependent values in the reach between She Oaks Weir and the confluence with the Barwon River.

Traditional Owners
Storage operator
Environmental water holder

System map

Moorabool System
Grey river reaches have been included for context. The numbered reaches indicate where relevant environmental flow studies have been undertaken. Coloured reaches can receive environmental water.

Environmental watering objectives in the Moorabool River

Landscape icon
Maintain channel form and processes

Maintain physical habitat diversity
Platypus icon
Maintain and improve a self-sustaining breeding population of platypus and support the dispersal of juveniles and the movement of adults
Plant icon
Maintain in-stream macrophyte communities Maintain streamside vegetation communities and promote recruitment
Insect icon
Maintain the abundance and diversity of waterbug communities
Water icon
Maintain water quality

Prevent hypoxic blackwater events
Fish icon
Improve and increase the distribution, abundance and diversity of migratory species (tupong, short-finned eel, common galaxias, spotted galaxias, short-headed lamprey and Australian grayling)

Maintain and increase the distribution, abundance and diversity of non-migratory species (flat-headed gudgeon, Australian smelt, southern pygmy perch and river blackfish)

Environmental values

The Moorabool river is a highly flow-stressed system, but it does retain significant environmental values. The river is home to native fish species including the Australian grayling, river blackfish, Australian smelt, flat-headed gudgeon, southern pygmy perch, short-finned eel, spotted galaxias, and tupong. The system also contains extensive areas of endangered remnant vegetation including streambank shrubland and streamside woodland ecological vegetation communities. Platypus, rakali (water rats) and a range of waterbugs are also present. The Moorabool River flows into the Barwon River, connecting it to the Ramsar-listed lower Barwon wetlands.

Recent conditions

Total rainfall in the Moorabool catchment in 2019–20 was slightly below the long-term average, but there was significant variation between and within seasons. Winter 2019 was wetter than average, and Lal Lal Reservoir filled to 99 percent capacity in November 2019. The second
half of spring and the first half of summer were drier than average, but February through to April 2020 saw a return to wetter-than-average conditions.

The wet winter provided some minor and moderate peaks in discharge in July and August 2019 as inflows continued to run off the catchment. As such, the recommended minimum low flows for winter and spring were met by natural inflows in 2019–20. Water for the environment was used to deliver freshes in August and October 2019, maintain low flows in reaches 3a and 3b throughout summer and autumn and to deliver targeted freshes throughout the system in summer and autumn.

The Moorabool River near Batesford (reach 4) stopped flowing in January 2020. This part of the river is directly connected to the underlying groundwater table and often ceases to flow in summer. As a result, low flow releases from Lal Lal Reservoir in January were increased from
five ML per day to 10 ML per day over a week to extend flow into reach 4. Water for the environment was also used to deliver freshes in late summer and autumn 2020 to cue the downstream migration of native fish, support platypus dispersal, flush the system and water the fringing vegetation.

Traditional Owner cultural values and uses

The Wadawurrung are Traditional Owners of the land of the Moorabool River and parts of the Barwon, Leigh and Yarrowee rivers. Eastern Marr Aboriginal Corporation also have Country within areas of the Barwon River.

During 2019, the Wadawurrung partnered with Corangamite CMA to complete an environmental flows study for the upper Barwon, Yarrowee and Leigh rivers. Environmental flows studies are essential technical references for river managers which identify the types of flows needed to support environmental and cultural values in a river system.

The cultural values identified in the flows study are applicable to all waterways within Wadawurrung Country, including the Moorabool River. The values include:

  • significant aquatic species such as buniya (eels), ware-up (river blackfish), tark (common reed) and bal-yun (cumbungi) which are traditional food, materials or medicinal sources
  • waterway confluences and deep pools which are places for meeting, ceremonies and trade and mark clan boundaries. Potential watering actions for the Moorabool River that support these values are identified in Table 1 using the icon below.

Potential watering actions for the Moorabool River that support these values are identified in Table 1 using the icon below.

Billabong icon

Watering planned and/or delivered in partnership with Traditional Owners to support Aboriginal cultural values and uses

Social, recreational and economic values and uses

In planning the potential watering actions in Table 1, Corangamite CMA considered how environmental flows could support values and uses including:

  • water-based recreation (such as kayaking, canoeing, fishing and swimming)
  • riverside recreation and amenity (such as birdwatching, walking, camping, picnicking and using parks and lookouts)
  • socio-economic benefits (such as diverters for irrigation, domestic and stock uses, and Geelong’s water supply).

Scope of environmental watering

Table 1 Potential environmental watering actions and objectives for the Moorabool system

Potential environmental watering action1

Functional watering objective

Environmental objective

Summer/autumn low flow (five ML/day continuous during December to May)

  • Maintain pool and riffle habitats for fish, waterbugs, platypus and submerged aquatic vegetation
  • Maintain water quality for biota during summer/autumn by reducing periods of low oxygen, high temperature and high electrical conductivity
Fish iconPlatypus iconPlant iconInsect iconWater drop icon

Winter/spring low flow (10–60 ML/day continuous during June to November)

  • Maintain connectivity and allow fish movement through the reach
  • Reduce intrusion by terrestrial vegetation into the stream bed

Fish iconPlant icon

Autumn fresh (one fresh of 60 ML/day for five days during April to May)

  • Provide a cue for the downstream migration and spawning of Australian grayling
  • Allow fish and platypus to move through the reach to access habitat
  • Maintain the condition of streamside vegetation
  • Flush silt and scour biofilms and algae from streambed and substrates to improve habitat quality for waterbugs

Fish iconMountain iconsInsect iconPlant iconPlatypus icon

Summer fresh (one fresh of 60 ML/day for five days during January to February)

Billabong icon
  • Provide a cue for downstream spawning and migration of short-finned eel
  • Allow fish and platypus to move through the reach to access habitat
  • Maintain the condition of streamside vegetation
  • Flush silt, scour pools and remove biofilms from hard substrates
  • Maintain water quality for biota by reducing periods of low oxygen, high water temperature and salinity

Fish iconMountain iconsPlatypus iconPlant iconInsect iconWater drop icon

Spring fresh (one or two freshes of 80–162 ML/ day for five days during September to November)

Billabong icon
  • Trigger the upstream migration of juvenile galaxias, tupong, short-finned eel and Australian grayling
  • Provide connectivity to support fish and platypus movement and maintain access to habitat
  • Scour biofilms and algae from the streambed and transport organic matter
  • Promote the growth and recruitment of streamside vegetation

Fish iconMountain iconsPlatypus iconPlant iconInsect iconWater drop icon

Winter fresh (one fresh of 80–162 ML/day for five days during May to August)

  • Trigger the downstream spawning migration of tupong
  • Allow fish and platypus to move through the reach and maintain access to habitat
  • Scour biofilms and algae from the streambed to maintain waterbug communities and transport organic matter to prevent blackwater events
  • Promote the growth and recruitment of streamside vegetation

Fish iconMountain iconsPlatypus iconPlant iconInsect iconWater drop icon

Summer/autumn fresh (one fresh of 30 ML/day for five days during February to March)1

  • Maintain water quality for biota by reducing periods of low oxygen, high water temperature and salinity

Water drop icon

Summer/autumn fresh (one fresh of 30 ML/day for five days during February to March)1

Engagement

Table 2 shows the partners and stakeholder organisations with which Corangamite CMA engaged when preparing the Moorabool system seasonal watering proposal.

Seasonal watering proposals are informed by longer-term regional catchment strategies, regional waterway strategies, environmental flow studies, water management plans and other studies. These incorporate a range of environmental, cultural, social and economic perspectives and longerterm integrated catchment and waterway management objectives. For further details, refer to the Corangamite Regional Catchment Strategy and the Corangamite Waterway Strategy.

Table 2 Partners and stakeholders engaged in developing the Moorabool system seasonal watering proposal

Partner and stakeholder engagement
  • Australian Platypus Conservancy
  • Geelong Landcare Network
  • Local community groups
  • Moorabool Stakeholder Advisory Committee
  • People for a Living Moorabool
  • Barwon Water
  • Central Highlands Water
  • Department of Environment, Land, Water and Planning - Water and Catchments
  • Southern Rural Water
  • Parks Victoria
  • Landholders on the Moorabool Stakeholder Advisory Committee
  • Recreational users on the Moorabool Stakeholder Advisory Committee
  • Wathaurung Aboriginal Corporation

Page last updated: 24/07/20