The Moorabool River flows southward from the Central Highlands between Ballarat and Ballan and joins the Barwon River at Fyansford. The Moorabool River, (Mooroobull Yluk) flows through Wadawurrung Country and has great cultural significance for Wadawurrung Traditional Owners.
The river’s catchment is heavily farmed, with about 65% of its 1,150km2 deemed as being agricultural-related land cover. It is a highly regulated waterway with three major water storages – the Moorabool, Bostock, and Lal Lal Reservoirs.
The Moorabool River Environmental Entitlement 2010 is held in the Lal Lal Reservoir and can store up to 7,086ML. This entitlement is subject to delivery rules (a maximum of 7,500ML over three years) which effectively provides the environment with an average of 2,500ML per year. No environmental entitlement exists for Bostock or Moorabool reservoirs, however passing flow rules are in place.
The Moorabool River is one of the most stressed rivers in Victoria, and as a water supply catchment with significant environmental values it is listed as a priority waterway in the Corangamite Waterway Strategy 2014-22.
Water for the environment can be released from Lal Lal Reservoir as base flow to maintain connectivity and provide fresh water for plants and animals. It can also be releases as a ‘fresh’ or a pulse of water which carefully timed to trigger fish migration and spawning.
Releases primarily affect the two river reaches (3a and 3b) immediately downstream of Lal Lal Reservoir. Some benefit can also be gained further down in reach 4, particularly when releases are piggy-backed on top of Barwon Water transfers between Lal Lal and Sheoaks, as ‘wetting up’ and evaporative losses are minimised.
Watering actions (or flow components) are informed by FLOWS studies (conducted every 5-10 years) and are delivered in a priority order guided by the science and water availability. In most years there is insufficient natural flow and environmental water to achieve all the recommended watering actions, so actions are prioritised starting with summer low flow, then winter low flow, then the most critical freshes. Approximately 1000ML is kept in reserve in case of drought. This water is only released in small bursts during a drought to prevent loss of aquatic plants and animals, such as fish and platypus.
It should also be noted that complementary actions such as removal of choking weeds and fish barriers are needed together with riparian and channel restoration to gain maximum benefit from the delivery of environmental water.
| Priority | Flow Component | Flow Objectives |
| 1 | Summer/autumn low flow (Dec-May ) 5 – 40 ML/day | Maintain minimum water quality for biota, maintain riffle habitats for fish, macroinvertebrates, Perridak Platypus and submerged aquatic vegetation during critical risk summer period. |
| 2 | Winter/spring low flow (June – Nov) 5 – 60 ML/day | Allow fish movement and maintain clear flow path and control intrusion by terrestrial vegetation. |
| ,3 | Summer/autumn fresh event (April/May) 60 – 80 ML/day for 5 days | Downstream spawning migration of Australian grayling. Flush silt, and scour biofilms from streambed, water fringing marginal zone vegetation, allow fish and Perridak platypus movement and maintain access to habitat. |
| 4 | Summer/autumn fresh event (Jan-Feb) 60 – 80 ML/day for 5 days | Downstream spawning and migration of Buniya Short-finned Eel. Flush silt, and scour biofilms from streambed, water fringing marginal zone vegetation, allow fish and Perridak platypus movement and maintain access to habitat. |
| 5 | Little summer fresh event (Feb-Mar) 30 – 60 ML/day for 3 days | Water fringing marginal zone vegetation. Allow fish and Perridak Platypus movement through the reach and maintain access to habitat. |
| 6 | Winter/spring fresh event (Sep – Nov) 80 – 90 ML/day for 5 – 10 days | Upstream migration of Juvenile Turrpurt galaxias, Tupong, Buniya short-finned eel and Australian grayling. Allow fish and Perridak platypus movement and maintain access to habitat. Flush silt, and scour biofilms and algae from streambed and transport organic matter. Promote growth and recruitment of native riparian vegetation including woody shrubs and promote strong vegetation zonation on the banks. |
| 7 | Winter/spring fresh event (May – Aug) 80 – 90 ML/day for 5 – 10 days | Downstream spawning migration of adult Tupong. Allow fish and Perridak platypus movement and maintain access to habitat. Flush silt, and scour biofilms and algae from streambed and transport organic matter. Promote growth and recruitment of native riparian vegetation including woody shrubs and promote strong vegetation zonation on the banks. |
| 8 | Winter/spring fresh event (Sep – Nov) 80 – 90 ML/day for 5 – 10 days | Upstream migration of Juvenile Turrpurt galaxias, Tupong, Buniya short-finned eel and Australian Grayling. Allow fish and Perridak platypus movement and maintain access to habitat. Flush silt, and scour biofilms and algae from streambed and transport organic matter. Promote growth and recruitment of native riparian vegetation including woody shrubs and promote strong vegetation zonation on the banks. To be delivered in addition to priority 6 in an average or wet year. |
The water year starts on July 1 each year. The timing for a lower priority flow component may come up before a higher priority flow component, so planning delivery requires careful consideration of available water and the long term weather forecast.
This document has been designed to cover Water for the Environment in the Moorabool River. It conveys what environmental water is for, why it is important and how delivery is managed.
The Moorabool Stakeholder Community Advisory Group (MSAC) was established by the Corangamite Catchment Management Authority (CCMA) to provide feedback on water management planning in the Moorabool River from a whole of community perspective.
64 Dennis Street, Colac VIC 3250
PO Box 159, Colac, VIC 3250
Hours: 8:30am – 5pm, Monday to Friday
T: 1800 002 262
E: info@ccma.vic.gov.au
54A Corio St, Geelong VIC 3220
Hours: 8:30am – 5pm, Monday to Friday
T: 1800 002 262
E: info@ccma.vic.gov.au
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