VEWH - Glenelg system

The Glenelg River rises in the Grampians and flows west through Harrow and then south to Casterton and Dartmoor. The Glenelg River estuary flows west from Dartmoor and passes through South Australia for a short distance before returning to Victoria and flowing into the sea at Nelson. At over 500 km, the Glenelg River is one of the longest rivers in Victoria.

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. Water for the environment is actively managed in the Glenelg River below Rocklands Reservoir. Passing flow rules are in place for the Glenelg River and upper Wannon River.

The priority reaches of the Glenelg River that can be targeted by environmental flow releases are Rocklands Reservoir to 5-Mile Outlet (reach 1a), 5-Mile Outlet to the confluence with the Chetwynd River (reach 1b), Chetwynd River to the Wannon River (reach 2) and Wannon River to the tidal extent just below the confluence with Crawford River (reach 3). Water for the environment in the Glenelg system is released from Rocklands Reservoir for reach 1a via the reservoir wall outlet and for reaches 1b, 2 and 3 via the 5-Mile and 12-Mile outlets.

The Glenelg River estuary benefits from releases of water for the environment to upstream reaches, but releases do not currently target the estuary. The Glenelg Hopkins CMA is investigating the influence of managed environmental water on the Glenelg River estuary, which is listed as a heritage river reach and a site of international significance under the Ramsar Convention.

Trial releases were delivered from Moora Moora Reservoir above Rocklands Reservoir (reach 0) in 2017–18, 2018–19 and 2019–20. The results of that trial will be analysed to inform future decisions about potential environmental water use in reach 0.

System map

Environmental watering objectives in the Glenelg system

Protect and increase populations of native fish

Maintain deep pool habitats and connectivity along the river

Maintain the platypus population

Maintain the health and increase the abundance of in-stream and streamside vegetation (such as river red gums and Wimmera River bottlebrush)

Maintain a wide range and large number of waterbugs to provide energy, break down organic matter and support the river’s food chain

Maintain water quality for native fish, waterbugs, aquatic vegetation and other water-dependent animals

Environmental values

The Glenelg River starts in the Grampians (Gariwerd) National Park and flows to the sea through the Lower Glenelg National Park. The lower reaches of the Glenelg River are part of a landscape recognised as one of Australia’s 15 national biodiversity hotspots, and the Glenelg Estuary and Discovery Bay site is Australia’s most recent listing under the Ramsar Convention.

The Glenelg River supports a range of rare and unique aquatic life including the endangered Glenelg freshwater mussel and Glenelg spiny crayfish. It is also home to platypus and populations of native fish including river blackfish, estuary perch, kooyang (short-finned eel), tupong and three species of pygmy perch including the threatened variegated and Yarra pygmy perches. Some of these fish species migrate long distances to and from the Glenelg River estuary to complete their life cycles.

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 streamside vegetation communities and species including the endangered Wimmera bottlebrush. Streamside and floodplain vegetation is comprised of river red gum woodlands with paperbark, bottlebrush and tea tree understorey.

Traditional Owner cultural values and uses

The Glenelg River, known as Bochara in Dhawuard Wurrung, Pawur in Bunganditj and Bogara in Wergaia- Jadawadjali languages, is a significant feature in the cultural landscape of south-western Victoria. The river features in creation stories from the region. Bochara-Bugara-Pawur continues to be an important place for Traditional Owners, who have inhabited the area for thousands of years, using the rich resources available along the river and associated habitats.

In planning for environmental flows in the Glenelg River, Gunditj Mirring Traditional Owners Aboriginal Corporation, Barengi Gadjin Land Council, Burrandies Aboriginal Corporation and Glenelg Hopkins CMA have considered:

supporting the health of cultural heritage sites, such as scar trees and the health of native plants which are sources of traditional foods and medicines
improved health and abundance of totem species and their habitat resulting from environmental watering also has benefits for Traditional Owner spiritual wellbeing
supporting contemporary cultural events (such as the Johnny Mullagh Cup).

Aboriginal peoples across the Glenelg catchment have retained a strong identity and connection to the traditional lands for which they have custodial rights and responsibilities. Traditional Owner values in the Bochara-Bugara-Pawur system align strongly with environmental values. Traditional Owner values are holistic and interrelated.

These values are bound up in the health of the river system overall, and the Country that the river is part of. Traditional Owner wellbeing is connected to the health of the river and the Country.

The Season Flows Calendar (Figure 1) illuminates flow regimes along one reach of the Glenelg River (reach 1b 5-Mile Outlet to Chetwynd River) and aligns them with corresponding environmental events and observations.

The value of the calendar is in its clear visual depiction of Traditional Owner knowledge, developed over many generations, of how varying flows correspond to seasonal conditions and broader environmental patterns. It is planned to embed the six seasons in the flow recommendations and scenario planning in the Glenelg Hopkins CMA watering proposal in future years.

The seasonal calendar arises from the six seasons of Gunditjmara country and was produced by Gunditj Mirring Traditional Owners Aboriginal Corporation. The northern part of the river upstream of Harrow area is in Jadawadjali Country and the south west part of the system is in Boandik Country. The calendar reflects seasonal flow conditions recognised by all the Traditional Owner groups.

Waterway managers are seeking opportunities to increase the involvement of Traditional Owners in environmental water planning and management. Where Traditional Owners are more deeply involved in the planning and/or delivery of environmental flows for a particular site, their contribution is acknowledged in Table 1 with an icon.

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

The timing of the summer fresh is planned to support the annual Jonny Mullagh Cup cricket match between the Gunditj Mirring and Barengi Gadjin Traditional Owners. The fresh will improve water quality in swimming holes and improve amenity for the Traditional Owners attending the cricket event, which is an important cultural event held on the river.

Social, recreational and economic values and uses

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

water-based recreation (such as canoeing and fishing)
riverside recreation and amenity (such as camping)
community events and tourism (such as the Johnny Mullagh Cup and visitation)
socio-economic benefits (such as diverters for irrigation, domestic and stock uses).

If the timing or management of planned environmental flows may be modified to align with a community benefit, this is acknowledged in Table 1 with an icon.

	Watering planned to support angling activities
	Watering planned to support water sports activities (e.g. canoeing)
	Watering planned to support peaks in visitation (e.g. camping or other public activities on long weekends or school holidays)

Environmental flow releases support the spawning and recruitment of popular angling species like estuary perch and bream. Local anglers continue to report increased fish activity associated with the delivery of freshes, improving fishing opportunities in the river. Releases support numerous fishing competitions including those of the Balmoral, Casterton and Dartmoor angling clubs.

The planning of the summer fresh improves accessibility, water quality and amenity for canoeists planning trips on the Glenelg River over the summer holiday period.

Summer and spring freshes provide a freshening flow which improves conditions at popular riverside campgrounds in the upper reaches of the Glenelg River including Fulham Reserve near Balmoral and the Johnny Mullagh Reserve at Harrow.

Recent conditions

The Glenelg region had near-average rainfall and above- average temperatures during 2019–20, with large rain events during winter/spring and throughout autumn contributing flows via tributaries below Rocklands Reservoir. Inflows into the Wimmera-Mallee headworks tracked well below average, although milder conditions meant that evaporation losses were lower than normal over summer/ autumn. On 1 April 2020, allocations reached 42 percent for the year for the Wimmera-Glenelg environmental entitlement. These allocations supplemented the 28,515 ML of environmental water carried over from 2018–19.

Natural flow in the Glenelg River provided required low flow and freshes during winter/spring 2019. These natural flows meant a proportion of prescribed passing flows could be withheld in winter and released in spring to meet Glenelg River flow objectives. Water for the environment was released from Rocklands Reservoir between November 2019 and May 2020 to maintain low flow and deliver summer/autumn freshes to provide habitat for native

fish, platypus and waterbugs, allow fish and platypus to disperse and support instream and streamside vegetation. A trial watering event from Moora Moora Reservoir to the upper Glenelg River (reach 0) was delivered in November and December 2019, to better understand how managed flows could be used to support plant, waterbug and animal populations above Rocklands Reservoir.

All of the high-priority potential watering actions for the Glenelg River below Rocklands Reservoir were met in 2019–20 through natural flows, passing flows, managed environmental flows or a combination of these. Continuous flows were maintained through the whole system, and several freshes were delivered during summer and autumn to flush pools and improve the quality of habitat for native fish and platypus. Different release patterns were trialled from Rocklands Reservoir, 5-Mile Outlet and 12-Mile Outlet during summer/autumn 2019–20 to understand the most efficient way of meeting environmental flow targets.

Low storage levels across the Wimmera-Mallee headworks mean that if dry conditions persist, environmental watering actions in the Glenelg River during 2020–21 will primarily focus on protecting water quality and refuge habitat in reaches 1 and 2, to prevent significant declines in native fish and platypus populations.

Scope of environmental watering

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

Potential environmental watering action	Functional watering objective	Environmental objective
Summer/autumn low flow in reach 1a (10 ML/day or natural during December to May)	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 wetted stream channel to promote the growth of in-stream vegetation and prevent encroachment by terrestrial plants
Summer/autumn low flow in reach 1b (15 ML/day or natural during December to May/Big Dry to Early Wet*)
Summer/autumn low flow in reach 2 (25 ML/day or natural during December to May)
Summer/autumn low flow in reach 3 (80 ML/day or natural during January to April)
Summer/autumn freshes in reach 1a (two freshes of 60 ML/day for two to three days during December to May)	Scour sand from pools to increase the quality and quantity of fish and waterbug habitat Wet emergent vegetation on the lower banks to improve its condition and prevent the encroachment of terrestrial species Flush pools to improve water quality and lower temperatures Provide sufficient flow to allow native fish and platypus to access habitat
Summer/autumn fresh in reach 1b (two freshes of 100 ML/day for two to three days during December to May/Big Dry to Early Wet*)
Summer/autumn fresh in reach 2 (two freshes of 150 ML/day for two to three days during December to May)
Summer/autumn fresh in reach 3 (two freshes of 150 ML/day for three days each or natural during January to April)
Autumn/winter low flows targeting reach 3 (260 ML/day or natural during May to June)	Wet benches to improve the condition of emergent vegetation and maintain habitat diversity Provide adequate depth for fish passage and cue fish movement Scour sand from pools to improve the quality of fish habitat Wet benches to improve the condition of emergent vegetation and maintain habitat diversity Wet benches to improve the condition of emergent vegetation and maintain habitat diversity
Winter/spring fresh in reach 2 (one to five freshes of 300 ML/day for one to five days during June to November)
Winter/spring low flow in reach 1a (60 ML/ day or natural during June to November)	Maintain water quality for fish and waterbugs Wet aquatic vegetation to maintain its condition and prevent encroachment by terrestrial species Maintain shallow-water habitat for fish, waterbugs and platypus
Winter/spring low flow in reach 1b (100 ML/day or natural during June to November/Big Wet to Fattening Up*)
Winter/spring low flow in reach 2 (160 ML/ day or natural during June to November)
Winter/spring low flow in reach 3 (400 ML/ day or natural during July to December)
Winter/spring low flow in reach 3 (400 ML/ day or natural during July to December)	Wet benches to increase habitat and allow widespread fish passage and keep the estuary mouth open (based on estuary mouth flows)

^* The six seasons of Gunditjmara country match to reach 1b watering, as Figure 1 shows.

Engagement

Table 2 shows the partners, stakeholder organisations and individuals with which Glenelg Hopkins CMA engaged when preparing the Glenelg 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 Glenelg Hopkins Regional Catchment Management Strategy and Glenelg Hopkins Waterway Strategy for further details.

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

Partner and stakeholder engagement
Friends of the Glenelg River Glenelg River User Group Department of Environment, Land, Water and Planning Grampians Wimmera Mallee Water Parks Victoria Victorian Fisheries Authority Wimmera Catchment Management Authority Individual landholders Balmoral Bush Nursing Centre Balmoral Post Office Glenelg River Boat Cruises Grampians Resort Nelson Boat and Canoe Hire Paestan Canoe Hire Vickery Brothers (sand extraction) Balmoral Angling Club Casterton Angling Society Dartmoor Angling Club Individual anglers South-west Fishing Reports VRFish Gunditj Mirring Traditional Owner Corporation Barengi Gadjin Land Council Burrandies Aboriginal Corporation

Partner and stakeholder engagement

Friends of the Glenelg River
Glenelg River User Group
Department of Environment, Land, Water and Planning
Grampians Wimmera Mallee Water
Parks Victoria
Victorian Fisheries Authority
Wimmera Catchment Management Authority
Individual landholders
Balmoral Bush Nursing Centre
Balmoral Post Office
Glenelg River Boat Cruises
Grampians Resort
Nelson Boat and Canoe Hire
Paestan Canoe Hire
Vickery Brothers (sand extraction)
Balmoral Angling Club
Casterton Angling Society
Dartmoor Angling Club
Individual anglers
South-west Fishing Reports
VRFish
Gunditj Mirring Traditional Owner Corporation
Barengi Gadjin Land Council
Burrandies Aboriginal Corporation

Page last updated: 22/01/21