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Reach 1 of the Coliban River below Malmsbury Reservoir to Lake Eppalock can benefit from environmental watering. An important distinction between the Coliban River and other regulated Victorian systems is the lack of irrigation demand in the river. Therefore, the river below Malmsbury has lower-than-natural flows year-round and environmental water is needed to provide adequate flow during summer and autumn. 

The VEWH does not have any environmental entitlements in the Coliban system, but passing flows can be managed to help mitigate some risks associated with critically low summer flow including low levels of dissolved oxygen. A small volume of Commonwealth environmental water is held in the system, but the high cost of delivery means there is no plan to use it in 2017–18.

Environmental watering objectives in the Colliban River

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Protect and increase populations of native fish by providing flows that allow movement and trigger spawning
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Maintain adequate diversity and biomass of waterbugs to provide energy, break down dead organic matter and support the river’s food chain
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Maintain fringing vegetation and in-stream plants
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Improve water quality and maintain healthy levels of dissolved oxygen in pools

Environmental values

The Coliban River provides important habitat for platypus, native water rats and small-bodied native fish (such as flatheaded gudgeon and mountain galaxias). The Coliban River also contains a diverse range of waterbugs supported by stands of emergent and submergent aquatic vegetation. It is bordered by remnant patches of streambank shrubland vegetation providing habitat for terrestrial animals. Historical records show that several native freshwater fish species including the Murray cod, river blackfish, Macquarie perch and Australian smelt once inhabited the river.

Social, cultural and economic values

Communities in Malmsbury, Taradale, Metcalfe and the surrounding area value the Coliban River for its aesthetic and recreational features including Ellis Falls and the Cascades. Popular recreational activities in the area include camping, fishing and birdwatching. The upper Coliban storages — Malmsbury and Lauriston Reservoir — supply urban, irrigation, stock and domestic demands in the surrounding area. The river and its adjacent lands are rich in cultural heritage with numerous scar trees, burial sites and artefacts recorded with Aboriginal Victoria. The Coliban River continues to be a place of significance for Traditional Owners who are now represented by the Dja Dja Wurrung Clans Aboriginal Corporation.

Conditions mid-2017

The start of the 2016–17 water year was dry and followed several years of mostly below-average streamflow. Therefore, a portion of passing flows was withheld at the beginning of the season to provide critical flows to the river over summer and autumn if dry conditions persisted. Conditions changed early in the year, and there was high rainfall and inflows to storages. The upper Coliban storages quickly filled and spills occurred between September and November providing several important flow events including winter freshes, winter bankfull flows and some small overbank flows. Overbank flows cannot be delivered with planned environmental releases because of infrastructure constraints and only occur when the storages spill.

After the spill event, passing flows were reduced to reserve water for use over summer and autumn. This meant flow in the lower reaches of the Coliban River quickly reduced and eventually ceased, turning lower reaches of the river into a series of disconnected pools. The flows delivered in 2016–17 were well below the environmental flow recommendations of the system except for the unregulated flow period of September to November and an unregulated flow event which reached the objectives of a summer/ autumn fresh in April.

Scope of environmental watering

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

Potential environmental watering

Environmental objectives

Summer/autumn freshes (5–15 ML/day for up to 2 weeks in December–May as required)1

  • Maintain water quality (including dissolved oxygen levels) and habitat for aquatic animals

Summer/autumn low flow (2–5 ML/day inDecember–May)

  • Maintain the aquatic vegetation
  • Maintain fish habitat
  • Maintain the permanent connectivity of the river for improved water quality
  • Maintain aquatic habitat for waterbugs
  • Maintain habitat for platypus

Summer/autumn freshes (of 50–160 ML/day for 3 days each in December-May)

  • Maintain riparian and in-channel recruiting vegetation
  • Provide native fish habitat, movement and spawning
  • Provide connectivity for water quality
  • Maintain aquatic habitat for waterbugs
  • Maintain habitat for platypus

1 The actual volume and duration of pulsed flows will depend on available water resources, climatic conditions and conditions within the river.

Risk management

In preparing its seasonal watering proposal, North Central CMA considered and assessed the risks of environmental watering and identified mitigation strategies. Program partners continually reassess risks and mitigation actions throughout the water year.


Waterway managers meet communities on environmental watering regionally, although other program partners also play a role.

In each region of Victoria, community engagement on environmental watering happens when environmental watering objectives and priorities are scoped (long term and annually), when delivering environmental water, and when reporting on environmental watering results.

In the North Central region communities are involved in decisions about the Loddon and Campaspe river systems, Murray river system including Gunbower Forest and some of the wetlands connected by the Wimmera-Mallee pipeline. This happens through formal advisory groups: Environmental Water Advisory Groups including river and wetland focused groups and the Gunbower Island Community Reference Group.

Who is engaged and how

Recreational users

Through formal advisory groups, recreational users provide local advice and raise opportunities for potential 'shared benefits' from environmental watering. Through Environmental Water Advisory Groups, recreational users are informed of environmental water deliveries and provide data that assists with reporting on the outcomes of environmental watering.

Goulburn-Murray Water engages with recreational user groups (such as Save Lake Eppalock and Lake Meran Users Group) that use water storages for recreation through planned consultations and meetings to discuss storage levels and potential impacts of environmental water releases from storages.

Environment groups

Through formal advisory groups, environment groups provide local knowledge, land management advice and advocate for the environment. They are also informed of environmental water deliveries and provide data that assists with reporting on the outcomes of environmental watering (including citizen science monitoring data such as providing bird counts).


Through formal advisory groups, farmers and landholders (including those who own private wetlands that receive environmental water) provide local knowledge and land management advice regarding environmental watering.

They are also informed of environmental water deliveries and provide data that assists with reporting on the outcomes of environmental watering. Goulburn-Murray Water engages (and often) with consumptive entitlement holders (often irrigators) and landholders (often with river frontages).

Traditional Owners

Through the North Central Catchment Management Authority Indigenous Facilitator, Traditional Owners from the Barapa Barapa, Dja Dja Wurrung and Yorta Yorta Nations are given the opportunity to provide input to seasonal watering proposals. The Catchment Management Authority and the Barapa Barapa Nation have conducted a cultural values mapping project in Gunbower Forest which will eventually enable cultural values to be incorporated in Gunbower environmental water planning. The Barapa Barapa and Yorta Yorta Nations undertake monitoring of cultural values in Gunbower Forest.

There are Dja Dja Wurrung and Yorta Yorta representatives from the North Central region who are members of the Murray Lower Darling Rivers Indigenous Nations. The Victorian Environmental Water Holder, the Commonwealth Environmental Water Holder and the Murray Darling Basin Authority engage the Murray Lower Darling Rivers Indigenous Nations on strategic (often longer term) issues related to environmental watering.


Councils are invited to participate in formal advisory groups meetings. Goulburn-Murray Water  consults with the City of Greater Bendigo, Gannawarra Shire and Swan Hill Rural City Council regularly on water management, including on environmental water management.

General public

The North Central Catchment Management Authority communicates and engages with the general public through their website, media releases, newsletters, public notices, community forums, community events (such as tours of Gunbower Forest during environmental watering), social media and direct contact to interested parties by email distribution list.