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The Glenelg River rises in the Grampians and flows west through Harrow and then south to Casterton and Dartmoor for over 500 km, making it one of the longest rivers in Victoria. A short stretch of the estuary winds through SA before returning to Victoria to enter the sea at Nelson.

The Glenelg River is an integral part of the Wimmera-Mallee headworks system, which supplies towns and properties across the Western Region. Moora Moora Reservoir and Rocklands Reservoir in the upper Glenelg catchment and three weirs on the upper Wannon River are all used to divert water from the Glenelg system to the Wimmera catchment. Environmental water is actively managed in the main stem of the Glenelg River below Rocklands Reservoir, and passing flow rules are in place for the Glenelg River and upper Wannon River.

The priority environmental flow reaches of the Glenelg River are Rocklands Reservoir to 5-Mile Outlet (reach 1a), 5-Mile Outlet to the confluence with the Chetwynd River (reach 1b) and Chetwynd River to the Wannon River (reach 2). Environmental water in the Glenelg system is released from Rocklands Reservoir for reach 1a via the reservoir wall outlet and for reach 1b via the 5-Mile and 12-Mile outlets. Releases are made at these points to meet objectives in these reaches as well as in reach 2. The Glenelg River reach 3 and estuary benefit from environmental water releases to upstream reaches, but releases are not specifically targeted at these reaches.

The Glenelg River above Rocklands Reservoir (reach 0) runs mostly through the Grampians National Park and retains significant environmental values. Flows through this reach are affected by the operation of Moora Moora Reservoir and work is being undertaken to confirm its flow requirements. Work is also being undertaken to better understand the role environmental releases from Rocklands Reservoir play in the health of the Glenelg River estuary, which is listed as a heritage river reach and has been nominated for international listing under the Ramsar Convention.

Storage manager
Environmental water holder

System map

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 Glenelg system

Plant icon
Assist in-stream and riverside plants to recover after disturbance from recent floods
Protect and increase populations of native fish

Cue fish movement and spawning to increase the recruitment of species such as the short-finned eel, black bream, estuary perch and tupong
Insect icon
Maintain a wide range and population of waterbugs to provide energy, break down organic matter and support the river’s food chain
Move built-up sand on the river bed to provide healthy habitat pools for native fish, platypus, the critically endangered Glenelg freshwater mussel and the endangered Glenelg spiny crayfish

Environmental values

The lower section of the Glenelg River is recognised as one of Australia's 15 national biodiversity hotspots due to the high-value aquatic life it supports including the endangered Glenelg freshwater mussel and Glenelg spiny crayfish. It is also home to platypus and important native fish populations including river blackfish, estuary perch, tupong and diverse pygmy perches. Some of these fish species migrate long distances upstream from the Glenelg River estuary to complete their lifecycles. Frasers Swamp is another important feature of the upper Glenelg system and is home to a healthy growling grass frog population.

The Glenelg River supports a variety of riparian vegetation communities including the endangered Wimmera bottlebrush. Riparian and floodplain vegetation is comprised of river red gum woodlands with paperbark, bottlebrush and tea tree understorey

Social, cultural and economic values

The Glenelg system is highly valued by recreational anglers and several fishing competitions are held on the river throughout the year along with high-profile events such as an Australian Bream Tournament and Fisheries Victoria's The Great Perch Search broodfish collection event. Other recreational activities including walking, sightseeing, boat cruises, canoeing, birdwatching and camping are popular along parts of the river. Many landholders rely on the Glenelg River for stock water and use the productive floodplains for grazing. The river provides tourism opportunities and supports businesses in townships (such as Harrow, Casterton, Dartmoor and Nelson). Maintaining healthy Country is vitally important to Aboriginal Victorians in the Glenelg River area including those represented by the Gunditj Mirring Traditional Owners Aboriginal Corporation and the Barengi Gadjin Land Council, and Aboriginal Victorians have a continuing connection to the river system.

Conditions mid-2017

Heavy rainfall in winter/spring 2016 ended a very dry 18 month period and led to widespread flooding throughout the Glenelg catchment. The floods connected the river and floodplain, provided a significant influx of carbon into the system, scoured woody debris and boosted food resources for aquatic species. The high flows also allowed migratory fish species to disperse throughout the system and recolonise areas that were unsuitable during the preceding dry period. Although not specifically measured, the natural high flows and floods probably provided cues and conditions for some fish species to breed. These natural flow events met many of the environmental flow objectives for winter and spring and so managed environmental flow releases were not needed. Passing flows were also suspended for much of winter/spring to reduce the flood risk to communities downstream of Rocklands Reservoir.

Environmental water allocations reached 100 percent in October 2016 for the first time since 2011–12. Water that was accumulated as a result of the suspended passing flows in winter was released from late November 2016 to help meet the recommended low flows and freshes through summer and autumn. Regulated environmental water releases began in April and will continue until the start of the next passing flow season in June 2017.

Scope of environmental watering

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

Potential environmental watering

Environmental objectives

Summer/autumn freshes targeting reach 1a (2 freshes of 60 ML/day for 2–3 days each in December–May)

  • Maintain or increase the abundance and variety of waterbugs
  • Scour sand from pools to increase the quality and quantity of fish habitat
  • Maintain the condition of emergent vegetation on the lower banks
  • Flush pools to improve water quality

Summer/autumn freshes targeting reaches 1b (2 freshes of 100 ML/day for 2–3 days each in December–May)

Summer/autumn freshes targeting reach 2 (2 freshes of 150 ML/day for 2–3 days each in December–May)

Summer/autumn low flows targeting reach 1a (10 ML/day or natural in December–May)1

  • Protect against rapid water quality decline over the low-flow period
  • Maintain edge habitats, pools and shallow water habitat for fish, waterbugs and platypus
  • Maintain a near-permanent inundated stream channel to prevent excessive in-stream terrestrial species growth and to promote instream vegetation

Summer/autumn low flows targeting reach 1b (15 ML/day or natural in December–May)1

Summer/autumn low flows targeting reach 2 (25 ML/day or natural in December–May)1

Winter/spring freshes targeting reach 1b (1–5 freshes of 250 ML/day for 1–5 days in June–November)2

  • Wet benches to improve the condition of emergent vegetation and to maintain habitat diversity
  • Provide adequate depth for fish passage and cue fish movement
  • Scour sand from pools to improve the quality of fish habitat
  • Maintain or increase vegetation diversity in the river and on channel benches

Winter/spring freshes targeting reach 2 (1–5 freshes of 300 ML/day for 1–5 days in June–November)

Winter/spring low flows targeting reach 1 a (60 ML/day or natural in June–November)1, 3

  • Maintain water quality for fish, waterbugs and aquatic vegetation
  • Maintain shallow water habitat for fish and waterbugs and facilitate the annual dispersal of juvenile platypus

Winter/spring low flows targeting reach 1b (100 ML or natural per day in June–November)1, 3

Winter/spring low flows targeting reach 2 (160 ML/day or natural in June–November)1, 3

Trial release to reach 0 (up to 50 ML/day over a 4–5 day period)
  • Develop an operational understanding of our ability to deliver environmental flows to support values in this reach including the capacity of infrastructure, metering and safety considerations

1 Cease-to-flow events occur naturally in the Glenelg system and may be actively managed. In the most recent flows study, the recommendation is that cease-to-flow events should occur as infrequently as possible and not exceed the duration of events that might have occurred naturally, to reduce stress on environmental values. Cease-to-flow events should be followed with a fresh.

2 Winter/spring freshes in reach 1a are important to the health of the Glenelg River but due to operational constraints and potential flooding risks achievement relies solely on natural events.

3 Passing flows provided under the environmental entitlement generally provide winter/spring baseflows. However, if passing flows are reduced, managed environmental water releases may be required to supplement them or to ensure appropriate rates of rise and fall and provide appropriate conditions in fresh events.

Risk management

In preparing its seasonal watering proposal, Glenelg Hopkins 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.

Communities in the Glenelg Hopkins region are involved in decisions about the Glenelg river system through the Glenelg Hopkins Catchment Management Authority advisory group.

Who is engaged and how

Recreational users

The Glenelg Hopkins Catchment Management Authority engages the Glenelg River Users Group directly through the Catchment Management Authority advisory group. The Catchment Management Authority also notifies the Glenelg River Users Group about planned environmental water deliveries and outcomes from environmental watering through email, SMS and social media.

The Catchment Management Authority engages local angling clubs on environmental watering on an as-needs basis.

Environment groups

The Catchment Management Authority notifies groups that advocate for the environment (primarily the Nelson Coastcare group, and also the Glenelg River Users Group) about planned environmental water deliveries and the beneficial environmental outcomes from environmental watering.


Landholders and industry groups (grains, beef, dairy, lamb and wool) sit on the Catchment Management Authority advisory group. Landholders are notified about planned environmental water deliveries (timing and duration) via SMS.

Landholders are also engaged through informal one-on-one meetings and are invited to fish survey days to assist in reporting outcomes of environmental watering.

Sand extractors in the Glenelg are informed of planned environmental water deliveries (timing and duration) via SMS and email (as environmental watering can impact on their business).

Traditional Owners

Gunditjmara and Eastern Maar peoples (separate, but related groups of native title holders in this region) are engaged via the Catchment Management Authority advisory group on long term and annual environmental watering priorities and objectives.

The Gunditj Mirring Traditional Owners Aboriginal Corporation and the Barengi Gadjin Land Council are both currently working with the Catchment Management Authority to undertake a water values and uses scoping project in the Glenelg river system, which will explore Traditional Owner management interests and aspirations in the Glenelg river system.


Consultation with the Southern Grampians Shire Council is issues focussed. The Southern Grampians Shire Council aim to protect the interests of the local community when it comes to environmental watering.

General public

The Catchment Management Authority engages and communicates with the general public about environmental watering via SMS, their website, and media releases.