Upper Barwon River Seasonal Watering Proposal 2021-22

FINAL Version 2, June 2021

Upper Barwon River Seasonal Watering Proposal 2021-22

Contents

Tables ...... ii Figures ...... ii Acknowledgement of Country ...... iii Preface for Version 2 ...... iv Executive Summary ...... v 1. Introduction ...... 1 1.1 System overview ...... 1 1.2 Environmental entitlement ...... 2 2. Engagement ...... 6 2.1 Notable feedback ...... 10 3. Values and uses of waterways ...... 11 3.1 Aboriginal cultural values and uses of waterways ...... 12 3.2 Social, recreational and economic values and uses of waterways ...... 16 4. Seasonal review 2020-21 ...... 18 4.1 Climate ...... 18 4.2 Environmental water delivery 2020-21 ...... 20 4.3 Hydrological achievement ...... 24 4.4 Key ecological observations ...... 28 4.5 Shared benefit review ...... 29 5. Environmental objectives and scope of environmental watering ...... 31 5.1 Water delivery objectives ...... 32 5.2 Flow recommendations and potential watering actions ...... 33 6. Scenario Planning ...... 41 6.1 Outlook for 2021-22 ...... 41 6.2 Scenario planning ...... 41 7. Delivery constraints ...... 46 7.1 Temporary constraints ...... 46 7.2 Systemic constraints ...... 46 8. Confounding factors ...... 48 8.1 Flow constrictions ...... 48 8.2 Riparian rehabilitation ...... 48 8.3 Fish barriers ...... 48 9. Increasing knowledge ...... 49 9.1 Knowledge gaps ...... 49 10. Risk management ...... 51

Corangamite Catchment Management Authority i

Upper Barwon River Seasonal Watering Proposal 2021-22

11. Approval and endorsement ...... 55 Appendix 1. Abbreviations ...... 56 Appendix 2. References ...... 57 Appendix 3. IAP2 spectrum of public participation ...... 58 Appendix 4. VEHW Risk matrix ...... 59

Tables

Table 1. A summary of the priority watering actions for 2021-22 ...... vii Table 2. Passing flow rules for the Upper Barwon ...... 3 Table 3. Stakeholder engagement for the Upper Barwon River SWP 2021-22 ...... 8 Table 4. Traditional Owner values and uses ...... 14 Table 5. Social, recreational, and economic shared benefits for the Upper Barwon River for 2021-22 ...... 17 Table 6. Hydrological achievement of flow compliance over time at Ricketts Marsh (Conns Lane, Birregurra): 2009-2021 ...... 26 Table 7. Hydrological achievement of flows 2020-21 at the east branch (East Barwon River at Flume) ...... 27 Table 8. Identified emerging patterns in environmental watering in Victoria and their relation to the Upper Barwon ...... 28 Table 9. Shared benefits review ...... 30 Table 10. Environmental watering priorities and the Upper Barwon entitlement beneficiaries ... 32 Table 11. Potential watering actions for 2021-22 ...... 35 Table 12. Planning of environmental watering under different climate scenarios ...... 43 Table 13. Risk assessment for 2021-22 ...... 52 Table 14. VEWH risk rating matrix ...... 59 Table 15. VEWH risk likelihood legend ...... 59 Table 16. VEWH risk consequence matrix...... 60

Figures

Figure 1. The Upper Barwon River System showing adopted study reaches and locations ...... 4 Figure 2. A typical section of the Upper Barwon east branch constrained by willows ...... 5 Figure 3. Red gums on the Upper Barwon ...... 11 Figure 4. River Blackfish (Gadopsis marmoratus) found in the Upper Barwon ...... 16 Figure 5. A comparison of monthly average rainfall at Mount Sabine 2000-2019, 2020 & 2021 19 Figure 6. Daily average stream flow at Ricketts Marsh and Winchelsea, 2020-21 ...... 19

Corangamite Catchment Management Authority ii

Upper Barwon River Seasonal Watering Proposal 2021-22

Figure 7. East branch flow against reach 4 flow recommendations in 2020-21 ...... 21 Figure 8. Dry period east branch flow against reach 4 flow recommendations in 2020-21 ...... 22 Figure 9. Daily average stream flow at Ricketts Marsh and flow recommendations achieved ... 23 Figure 10. Flow recommendations for the Barwon River ...... 31 Figure 11. IAP2 spectrum of public participation ...... 58

Acknowledgement of Country

The Corangamite Catchment Management Authority (CCMA) wishes to acknowledge the Eastern Maar and Wadawurrung, Traditional Owners of the land of the Barwon River. We pay our respects to their Elders past, present and emerging. We commit to continuing to work with all Traditional Owners to ensure their knowledge and culture is included and valued in CCMA planning and delivery.

Corangamite Catchment Management Authority iii

Upper Barwon River Seasonal Watering Proposal 2021-22

Preface for Version 2

Version 2 of the Upper Barwon River Seasonal Watering Proposal 2021-22 supersedes all previous versions. Version 2 has been issued due to a correction to the Upper Barwon, Yarrowee and Leigh Rivers FLOWS study update (Alluvium 2019) which was re-issued in June 2021 as the Upper Barwon Upper Barwon, Yarrowee and Leigh Rivers FLOWS study update (Alluvium 2021).

The 2021 version of the FLOWS study update provides an update to the recommendations provided in the May 2019 version of the original report. These updates include: • Updates to flow frequency recommendations for all reaches • Use of ‘reference’ reaches for nearby waterways not included in this FLOWS study

This has translated to a halving of the frequency of freshes proposed in this Upper Barwon River Seasonal Watering Proposal 2021-22. This affects potential watering actions - priorities 2 and 5. Changes have been made to Table 1 in the Executive Summary, Table 11 in Section 5, and some accompanying text, accordingly. In addition, all references to the FLOWS study update have been revised to the 2021 version throughout version 2 of this document.

This correction has not had any implications for the management of the entitlement to date.

Corangamite Catchment Management Authority iv

Upper Barwon River Seasonal Watering Proposal 2021-22

Executive Summary

This Seasonal Watering Proposal (SWP) outlines the Corangamite Catchment Management Authority’s (CCMA) proposed priorities for the use of environmental water from the West Barwon Reservoir within the Upper Barwon River system in 2021-22, as required under section 192A of the Water Act 1989. The Victorian Environmental Water Holder (VEWH) will use the SWP to inform the development of the Seasonal Watering Plan 2021-22

The Barwon River rises in the Otway Ranges and flows close to the townships of Forrest, Birregurra, Winchelsea and Inverleigh, before flowing through Geelong and the Lower Barwon Wetlands, joining the coast at Barwon Heads. The current environmental water entitlement held in the West Barwon Reservoir can only provide environmental water to the Upper Barwon east branch, the Upper Barwon west branch, with diminishing effect to reaches in the main Barwon River channel.

The Upper Barwon is facing environmental challenges due to a lack of environmental flow, largely due to the ongoing impact of the West Barwon Reservoir with insufficient environmental entitlement. There are a range of other contributing factors including land use change, physical constrictions, a drying climate and groundwater extraction by a range of users. Two key issues have been raised by the Upper Barwon Surface Water Advisory Group (UBSWAG) for acknowledgement in preparing previous proposals.

1. Potential impacts of historical Barwon Downs ground water extraction: Barwon Water has acknowledged potential impacts to the flows in the upper reaches and committed to monitoring to confirm impact, and remediation if required. 2. The river appears to have been disappearing to ground in the mid-Barwon between Winchelsea and Inverleigh gauges: The cause is unknown, but it is likely the water is going underground.

This SWP has been developed in consultation with the UBSWAG. The Traditional Owners of the Upper Barwon, the Eastern Maar Aboriginal Corporation (EMAC), were invited to be involved in the development of this SWP and Wadawurrung Traditional Owner Aboriginal Corporation (WTOAC) were consulted on the elements of the document relating to Wadawurrung Country only.

Corangamite Catchment Management Authority v

Upper Barwon River Seasonal Watering Proposal 2021-22

The environmental watering objective for the Upper Barwon, developed by UBSWAG in 2017, is:

‘To improve the Barwon River’s flow-dependent ecological values and services through the provision of environmental water. The delivery of environmental water will also provide for social and cultural values for future generations.’

In line with this objective, the CCMA proposes to use the entitlement of approximately 1,000ML of water in 2021-22 for ecological outcomes and to realise shared benefits wherever possible, without compromising ecological outcomes. This is due to the entitlement being less than the FLOWS study recommendations.

Lessons from the previous three watering years have informed this year’s SWP. The delivery of environmental water down both the Upper Barwon west and Upper Barwon east branches has been problematic, because both are significantly choked with glyceria and willows. The Upper Barwon, Yarrowee and Leigh rivers FLOWS study update (Alluvium 2021) defines the Upper Barwon east branch as a higher priority for environmental releases than the Upper Barwon west, and the first releases were made down this branch in January 2020. As with releases down the west branch in 2019, releases down the east caused localised flooding due to flow constrictions, despite delivering a reduced peak of 15 ML/d down from the recommended 35 ML/d. Flow peaks were subsequently reduced further to 9 ML/d to avoid flooding. This experience has informed delivery planning in 2020- 21 and 2021-22. Constriction issues pose a significant problem for environmental flows in the Upper Barwon. CCMA is working towards defining the extent of the problem and investigating solutions.

The Upper Barwon, Yarrowee and Leigh rivers FLOWS study update (Alluvium 2021) has recommended that an additional 44GL/year of water is required to return the Barwon system to within 75% of the natural flow regime and allow for the provision of all environmental flow recommendations. This includes 29GL down the Upper Barwon section (excluding the Yarrowee-Leigh). An additional 2.34GL/year is required just to meet dry period low and dry period fresh recommendations down the Upper Barwon. The current allocation of 1GL/year is drastically insufficient to meet the river’s health requirements, even when just considering the reaches that are immediately downstream of where the entitlement is held.

As the entitlement cannot meet all flow recommendations for the Upper Barwon east and west branches, watering actions have been prioritised, as summarised in Table 1 below.

Corangamite Catchment Management Authority vi

Upper Barwon River Seasonal Watering Proposal 2021-22

Table 1. A summary of the priority watering actions for 2021-22 Environmental allocation: ~1,000ML/year Is this in line with the FLOWS study update? Priority 1: Upper Barwon east branch low flows of 0.5 ML/day between Yes December – May Priority 2: 2 x 9-15ML/day freshes in the Upper Barwon east branch over No, the FLOWS study recommends two days between December – May 35 ML/day, however the current flow constrictions don’t allow this. Where water is available: Priority 3: Upper Barwon west branch low flows of up to ~30ML/day Yes between December – May Priority 4: Upper Barwon east branch low flow of 10ML/day (or natural if Yes available) between June – November Priority 5: 5 x ~50ML/day freshes in the Upper Barwon west branch over No, the FLOWS study recommends 6 days, between December – May 100 ML/day, however the flow constrictions and the current entitlement does not allow this. Priority 6: Maintain Upper Barwon west branch low flow of ~50ML/day No, the FLOWS study recommends between June – November 100 ML/day or natural, however the flow constrictions current entitlement does not support this.

Corangamite Catchment Management Authority vii

Upper Barwon River Seasonal Watering Proposal 2021-22

1. Introduction

This SWP outlines the CCMA’s proposed priorities for the use of environmental water in the Upper Barwon River system in 2021-22, as required under section 192A of the Water Act 1989 and outlined in the Central Sustainable Water Strategy (Department of Environment, Land, Water and Planning, 2006). The VEWH will use the SWP to inform the development of the Seasonal Watering Plan 2021- 22.

1.1 System overview

The Barwon River rises in the Otway Ranges and flows close to the townships of Forrest, Birregurra, Winchelsea, and Inverleigh before flowing through Geelong and the Lower Barwon Wetlands, joining the coast at Barwon Heads. The Leigh River, a major tributary, rises near Ballarat and joins the Barwon River at Inverleigh. Two other tributaries, Birregurra and Boundary Creeks, flow into the Barwon from the western part of the catchment

The Barwon River is a major water supply for Geelong, the smaller urban centres, and farm water supply for the region. The system is significantly altered due to on-stream reservoirs, extensive farm dam storages, and many diversion licenses. Inter-basin transfers can potentially occur from Lake Colac (via the Lough Calvert drainage scheme) and Lake Corangamite (via the Woady Yaloak drainage scheme) into the Barwon River. Parts of the landscape zone near the headwaters of the Barwon River and several of its tributaries include the Otway Ranges. Parts of both the Great Otway National Park and Otway Forest Park are in the catchment.

The Upper Barwon is facing environmental challenges due to a lack of environmental flow, largely due to the ongoing impact of the West Barwon Reservoir with insufficient environmental entitlement. There is a range of other contributing factors including land use change, physical constrictions, a drying climate and groundwater extraction by a range of users. Two key issues have been raised by the UBSWAG for acknowledgement in preparing previous proposals.

1. Potential impacts of historical Barwon Downs ground water extraction. Barwon Water has acknowledged potential impacts to the flows in the upper reaches and committed to monitoring to confirm impact, and remediation if required. 2. The river appears to have been disappearing to ground in the mid-Barwon between Winchelsea and Inverleigh gauges. The cause is unknown, but it is likely the water is going underground.

Corangamite Catchment Management Authority 1

Upper Barwon River Seasonal Watering Proposal 2021-22

1.2 Environmental entitlement

The Upper Barwon Environmental Entitlement was established in 2018 to provide water for the environment in the Upper Barwon River system in Victoria. The Victorian Environmental Water Holder (VEWH) is entitled to a 2000ML share of storage capacity in the West Barwon Reservoir, and 3.8% of inflows. This results in approximately 1,000ML per year specific to the West Barwon Reservoir.

The Upper Barwon, Yarrowee and Leigh rivers FLOWS study update (Alluvium 2021) was undertaken to identify the flow requirements of freshwater reaches of these river systems. It replaces an earlier study. The new study divides the Barwon River downstream of the West Barwon Reservoir into seven reaches above the confluence with the Leigh River, based on geomorphology, hydrology, system operation and natural values, as outlined below in Figure 1. The current entitlement in the West Barwon Reservoir can provide environmental water directly to two reaches: the Upper Barwon east branch and the Upper Barwon west branch. The entitlement has a diminishing effect on reaches in the main Barwon channel past the confluence of the Upper Barwon east and west branches. It should be noted that although the West Barwon Reservoir is situated on the Upper Barwon west branch, water can be released down the Upper Barwon east branch (through a diversion channel) as well as to the Upper Barwon west branch.

The 2021 FLOWS study update has recommended that an additional 44GL/year of water is required to return the Barwon system to within 75% of the natural flow regime and allow for the provision of all environmental flow recommendations. This includes 29GL down the Upper Barwon section (excluding the Yarrowee-Leigh). An additional 2.34GL/year is required just to meet dry period low and dry period fresh recommendations down the Upper Barwon. The current allocation of 1GL/year is drastically insufficient to meet the river’s health requirements, even when just considering the reaches that are immediately downstream of where the entitlement is held.

Passing flows are an important source of water for the Upper Barwon River and where opportunity exists, the environmental entitlement will be used to enhance these flows. Passing flow rules for the Upper Barwon are outlined in Table 2. Barwon Water must provide an instantaneous flow below the diversion weirs of the lesser of the minimum passing flow as specified in Table 2 and the natural flow.

Corangamite Catchment Management Authority 2

Upper Barwon River Seasonal Watering Proposal 2021-22

Table 2. Passing flow rules for the Upper Barwon Minimum Passing Flows, April to December (inclusive) System storage volume is less than 40,000ML System storage volume is greater than 40,000ML West Barwon River 4 5 East Barwon River 1 5 except during September

Minimum Passing Flows, January to March (inclusive) System storage volume is less than System storage is greater than for January - 26,100ML for January - 26,100ML for February - 22,900ML for February - 22,900ML for March - 20,900ML for March - 20,900ML West Barwon River 4 4 East Barwon River 1 Pass natural Flow

Corangamite Catchment Management Authority 3

Upper Barwon River Seasonal Watering Proposal 2021-22

Figure 1. The Upper Barwon River System showing adopted study reaches and locations

Corangamite Catchment Management Authority 4

Upper Barwon River Seasonal Watering Proposal 2021-22

The FLOWS study update (Alluvium, 2021) states that effective delivery of environmental water to achieve flow objectives in relevant reaches will only be possible through an integrated program of complementary actions and environmental water delivery. Importantly these complementary actions must include management of flow limiting infrastructure and choking weed infestations in the upper reaches, as captured in Figure 2 below. Flow limitations were observed during the first summer fresh delivered down the west branch in February 2019 and down the east branch in January 2020. These issues are further outlined below in Section: 7 Delivery Constraints and Section 8 Confounding Factors.

Figure 2. A typical section of the Upper Barwon east branch constrained by willows

Corangamite Catchment Management Authority 5

Upper Barwon River Seasonal Watering Proposal 2021-22

2. Engagement

The CCMA has engaged with the UBSWAG during the development of this plan. The UBSWAG was established by the CCMA in 2017 to support the development of SWPs. The group also support other important scientific studies relating to flows in the river. The UBSWAG is a passionate and dedicated group of individuals, community groups and government representatives that have a broad combination of skills including technical knowledge, historical information and an understanding of government policy and community values. In 2018 the UBSWAG played a key role in determining the ecological values, objectives, threats, and opportunities for the Upper Barwon River to inform the new Upper Barwon-Yarrowee Leigh FLOWS study update (Alluvium, 2021). The group also has a key role in informing the watering priorities in the SWP each year.

Together with the UBSWAG, CCMA engaged with Traditional Owners, the WTOAC on all activities relating to the management of environmental water in the Barwon River on Wadawurrung Country, including this SWP. The WTOAC collaborated on the technical panel of the FLOWS study update 2021, a state first. The partnership that CCMA has with the WTOAC has led to the recognition of the cultural values of rivers on Wadawurrung Country within this and other SWPs on Wadawurrung Country. The UBSWAG are notified of all environmental flow releases throughout the year, and CCMA also work with stakeholders individually on specific issues related to the management of environmental water as they arise.

EMAC have recently acquired registered aboriginal party (RAP) status. The CCMA has also reached out to the EMAC to incorporate their views and priorities into the management of environmental water in the upper reaches of the Barwon River, but they were unable to participate. The CCMA will continue to seek their input into the future.

This watering proposal is underpinned by technical expertise and advice; However, local and Traditional Owner knowledge and input from the Wadawurrung regarding their Country has added significant value, in particular:

• Feedback and advice on the landscape characteristics of the reaches and any other localised considerations or observations relating to the rivers • The realities and feasibility of water delivery volumes and timing • Anecdotal observation and accounts of environmental watering in 2019-20 • New and emerging shared benefits because of the watering

Corangamite Catchment Management Authority 6

Upper Barwon River Seasonal Watering Proposal 2021-22

In line with the Victorian Government best practice for public participation guidelines, Table 3 below defines the level of participation, timing and method of engagement with stakeholders during the development of the SWP. The International Association for Public Participation (IAP2, 2018) spectrum of public participation is designed to assist with the selection of the level of participation that defines the public’s role in any community engagement program and can be found in Appendix 3.

Corangamite Catchment Management Authority 7

Upper Barwon River Seasonal Watering Proposal 2021-22

Table 3. Stakeholder engagement for the Upper Barwon River SWP 2021-22 Who Stakeholders IAP2 Engagement method Engagement level purpose Community • Friends of the Barwon Involve Membership on UBSWAG • Seek user input groups and • Land and Water to the environment Resources Otway • Meeting to discuss and seek input on draft proposal development of groups the proposal. Catchment (LAWROC) • Review of draft proposal and opportunity to provide formal feedback. • Review previous • Geelong Field environmental • Response to stakeholders on how their feedback influenced Naturalists Club watering actions • Otway Agroforestry the SWP and why. and seek Network feedback on any • Winchelsea Landcare Direct engagement (1-on-1). outcomes and capture Group Attendance at community forums. observations. • Upper Barwon • Provide an Landcare Network opportunity for • Environment Victoria individuals, agencies and groups to Government • Department of Involve Membership on UBSWAG contribute to the agencies Environment, Land, proposed Water and Planning • Meeting to discuss and seek input on draft proposal watering actions and intended (Water & Catchments). • Review of draft proposal and opportunity to provide formal outcomes. • Barwon Water feedback. • Southern Rural Water • Identify • Response to stakeholder on how their feedback influenced the • VEWH opportunities to SWP and why. achieve shared • Partnership meetings with links or relevance to seasonal benefits. water proposal development. • Assist in

increasing Direct engagement (1-on-1) (UBSWAG). awareness and Attendance at community forums. understanding of

Corangamite Catchment Management Authority 8

Upper Barwon River Seasonal Watering Proposal 2021-22

Who Stakeholders IAP2 Engagement method Engagement level purpose Landholders • Individuals represented Involve Membership on UBSWAG the purpose and /farmers & on UBSWAG objectives of the recreational • Meeting to discuss and seek input on draft proposal environmental users • Review of draft proposal and opportunity to provide formal watering program feedback. for the Upper • Response to stakeholder on how their feedback influenced the Barwon River. SWP and why.

Direct engagement (1-on-1).

Attendance at community forums. Traditional Wadawurrung Traditional Consult • Directly consulted on the applicable cultural aspects within the Owners Owners Aboriginal 2021-22 SWP draft. Corporation (WTOAC) • Invited to attend community forms • Meeting to discuss and seek input on draft proposal • Review of relevant sections of draft proposal and opportunity to provide formal feedback. • Partnering to create the FLOWS study update (Alluvium 2021), which underpins the SWP. Eastern Maar Aboriginal Inform • Invited to participate (NB: involvement sought via email as Corporation (EMAC) recommended)

Local Colac Otway SC Consult Membership on UBSWAG Government • Meeting to discuss and seek input on draft proposal • Review of draft proposal and opportunity to provide formal feedback. • Response to stakeholder on how their feedback influenced the SWP and why.

Direct engagement (1-on-1).

Attendance at community forums.

Corangamite Catchment Management Authority 9

Upper Barwon River Seasonal Watering Proposal 2021-22

2.1 Notable feedback

The Upper Barwon Seasonal Watering Proposal 2021-22 was presented and distributed to UBSWAG and other community and agency members in February 2021. Individuals had two weeks to provide feedback to CCMA.

Feedback from community included enquiries around fish monitoring on the Upper Barwon River and mechanisms for recovering more water for the river. The latter enquiry was made in the context of frustration regarding the insufficiency of the environmental entitlement. Excellent observations on shared benefits were also provided by community.

Detail of the comments received, and CCMA’s responses can be found in the Upper Barwon SWP 2021-22 Comments Register. Detail of the comments received (other than letters of support) and CCMA responses are provided to the UBSWAG. Other individuals or organisations can contact the CCMA at [email protected] to request a copy of the Upper Barwon SWP 2021-22 Comments Register.

Corangamite Catchment Management Authority 10

Upper Barwon River Seasonal Watering Proposal 2021-22

3. Values and uses of waterways

The primary purpose of environmental water entitlement is to achieve environmental outcomes. However, the delivery of environmental water is likely to provide other benefits that depend on the condition of our waterways, such as supporting social and cultural values. Shared benefits are the many recreational, social, economic and Aboriginal cultural benefits that occur because of environmental watering, such as fishing, boating, bird watching, community events and supporting Traditional Owner values and events. Opportunities for shared benefits are incorporated into planning and watering decisions if they do not compromise environmental outcomes.

The CCMA is flexible in its delivery approach and aspires to realise shared benefits that arise from the delivery and use of the water, where possible.

Through the management of the Upper Barwon Environmental Entitlement 2018, the CCMA consults with stakeholders to ensure that consideration is given to social, cultural and economic matters relevant to water management for the Upper Barwon. Figure 3 shows the shared benefit of amenity on the Upper Barwon.

Figure 3. Red gums on the Upper Barwon (CCMA, 2017)

Corangamite Catchment Management Authority 11

Upper Barwon River Seasonal Watering Proposal 2021-22

3.1 Aboriginal cultural values and uses of waterways

The Barwon River has important social, cultural and economic values. Both Eastern Maar and Wadawurrung Traditional Owners have a strong connection and place a high cultural value on the Barwon River. Many Eastern Maar and Wadawurrung people in the region have a connection and a long history with the river.

The reaches of the Barwon River that can be most influenced by water delivered from the West Barwon Reservoir sit in Eastern Maar Country, upstream of Winchelsea. In February 2020, EMAC received RAP status over a large portion of land in south-west Victoria, which includes the Barwon River upstream of Winchelsea. This status recognises Eastern Maar as the primary guardians, keepers and knowledge holders for the management and protection of Aboriginal cultural heritage within the determined area. EMAC (2015) Country Plan (Meerreengeeye ngakeepoorryeeyt) identifies healthy country and sustainable use of natural resources as a goal. While cultural values have not yet been formally defined with the Eastern Maar there are opportunities within relevant reaches for actively managed shared benefits in the future.

The WTOAC released their Paleert Tjaara Dja - let’s make Country good together 2020-2030 - Wadawurrung Country Plan in 2020 (WTOAC, 2020). Yulluk – waterways, rivers, estuaries and wetlands, is a key value identified in the plan to be looked after. Consultation is ongoing, and meetings are held regularly with the Wadawurrung to help progress future projects and work together to expand on the opportunities for shared benefits.

The following Wadawurrung cultural values and recommendations are applicable across all sites within Wadawurrung Country, including the Barwon River south of Winchelsea:

• Maintaining watering requirements for healthy, thriving, culturally significant species is crucial • Protection of totem species is priority • Recognition of confluences as places of meeting, ceremony and trade • Identifying Clan boundaries with confluences • Maintain deep/permanent waterholes and refuge pools • Maintain access to culturally important sites – story places, ceremonial places • Protection of all Wadawurrung cultural heritage • Use of appropriate Wadawurrung language for places of cultural importance on Wadawurrung Country • Increased opportunities for Wadawurrung Traditional Owners to be involved in monitoring and evaluation activities on Wadawurrung Country • Increased opportunities for Wadawurrung Traditional Owners in all communications of environmental water releases and activities on Wadawurrung Country

Corangamite Catchment Management Authority 12

Upper Barwon River Seasonal Watering Proposal 2021-22

The CCMA is continuing discussions with EMAC and WTOAC to continue cultural value mapping, to aid understanding of Aboriginal outcomes from environmental water and explore culturally beneficial opportunities. Key Wadawurrung cultural objectives and values as identified in Upper Barwon Yarrowee and Leigh River FLOWS study update (Alluvium 2021) are found below in Table 4.

Corangamite Catchment Management Authority 13

Upper Barwon River Seasonal Watering Proposal 2021-22

Table 4. Traditional Owner values and uses River Traditional Category Objectives & Values & uses How will this opportunity be Owner group opportunities considered environmental watering in 2021-22? Upper Wadawurrung Culturally Maintain or improve Meat and pelt Environmental watering will aim to Barwon Traditional Significant abundance, breeding and provide pool habitat and connectivity Owner Species recruitment of Wad-dirring/ between reaches where possible. Aboriginal Perridak (platypus). Corporation Maintain or improve Meat, important food source sometimes Where possible, environmental watering (WTOAC) abundance of Buniya smoked. aims to provide for pools, habitat and (Eels). food sources, as well as providing water over riffles to allow eels to migrate. Maintain or improve Meat Where possible environmental watering abundance of Turrpurt aims to provide for pools, habitat and (Native trout galaxias spp.) food sources, provide water over riffles to allow fish to move between pools and Maintain or improve Meat breed, feed and find new habitats. abundance of Ware-rap (Blackfish). Maintain or improve Environmental watering aims to maintain Plant food, finger shaped tubers are abundance of Polango/ adequate depth of water in channel crisp and sweet. Cooked in ground Warngare (Water ribbons where possible. oven Triglochin procera). Maintain or improve Tark: Weapon-stems used for spear Where possible, environmental watering condition, extent and shafts for fishing. Reed cut while still aims to maintain adequate depth of water abundance of Tark green to make necklaces, weaving- to limit terrestrial encroachment into (common reed Phragmites bags and baskets; also a food plant. aquatic habitats. This will also support australis), Toolim (Pale Toolim: Weaving baskets growth on terraces, channel edge and Rush Juncus pallidus), and Bal-yan: Fluff used to pack wounds lower bank. Bal-yan (Cumbungi Typha under paperbark bandage latifolia)

Corangamite Catchment Management Authority 14

Upper Barwon River Seasonal Watering Proposal 2021-22

River Traditional Category Objectives & Values & uses How will this opportunity be Owner group opportunities considered environmental watering in 2021-22? Maintain or improve Bark removed for canoe, shelter and abundance of Biyal (River tools, Tarnuk (bowl); nectar drink; red gum Eucalyptus medicinal – gum or sap was used for camaldulensis) burns to shrink or seal them, the sap is high in tannin. Leaves for steam baths. Maintain or improve Larrap: Timber used for making club- Environmental watering cannot consider abundance of Larrap shields called Malka. Sap-sucking lerp this in 2021-22 due to various constraints (Manna gum Eucalyptus bug gathered each season Young such as an insufficient entitlement. viminalis) and Kokibainang leaves were fed onto fire near patient. (swamp wallaby grass Poultice of well-chewed leaves applied Amphibromus reservatus). for back ache. Quail flocks attracted to Manna. Kokibainang: Leaves split, dried out and re-constituted in running water. Fibres twisted into rope to make long nets for game hunting. Physical Deep pools The presence of deep pools has Environmental watering will supplement Features cultural significance. in filling and ensuring connectivity to pools where possible. Confluences High cultural value due to historical use Where possible, environmental watering of site as a meeting place for three will aim to supplement adequate depth of different Clans. water for connectivity. Events Holding cultural events on Celebration of culture, family events, Due to a limited entitlement, fresh events the Upper Barwon fishing days, cultural festivals. to support events are not possible on Wadawurrung country due to its lack of proximity to the release point.

Corangamite Catchment Management Authority 15

Upper Barwon River Seasonal Watering Proposal 2021-22

3.2 Social, recreational and economic values and uses of waterways

The adjacent land use of the Upper Barwon River is dominated by grazing for livestock (beef, sheep and dairy) and forestry, and is significant in terms of economic value. There is limited public access to river frontage, therefore social and recreational values and uses of the Upper Barwon are also limited. Recreational use tends to be informal and often on private land in the form of swimming and fishing. There are some public areas through towns such as Forrest, Birregurra and Winchelsea where people may gain access to frontage for camping, swimming, walking or fishing. The CCMA has contacted Colac Otway Shire to enquire if there are any events that we should be aware of and that can be supported through delivery of environmental water. Opportunities to support social, recreational and economic values are incorporated into planning and watering decisions if they do not compromise environmental outcomes.

The presence of environmental water in the river does support a range of informal activities, such as fishing (e-water supports a population of native species such as the River Blackfish (Figure 4) swimming, camping and bird watching. Relevant social, recreational and economic values and uses are listed in Table 5 below.

Figure 4. River Blackfish (Gadopsis marmoratus) found in the Upper Barwon (Photo: ARI 2019)

Corangamite Catchment Management Authority 16

Upper Barwon River Seasonal Watering Proposal 2021-22

Table 5. Social, recreational, and economic shared benefits for the Upper Barwon River for 2021-22 Waterway Beneficiary Connection to the river Values / uses / objectives / How have these benefits been opportunities considered?

Upper Recreation: Recreational fishing is important for A healthy fish population is Environmental watering supports a Barwon fishing social and recreational purposes. important as it provides healthy system. Low flow watering River Recreational fishers have an opportunities for recreational aids in supporting connectivity interest in maintaining a healthy fishing. throughout the reaches and allows system. fish to move. Fresh events aid in maintaining and expanding migratory fish populations as they trigger migration and support their life cycle.

Upper Recreation: Water based recreational activities Adequate water quality, depth and Environmental watering where Barwon e.g. are important for social and connectivity is important for those possible supports a healthy, flowing River canoeing, recreational purposes. Those who who are engaging in recreational and connected system with swimming engage with the natural water activities. adequate depth to ensure more environment are likely to support opportunities for those engaging in the idea of maintaining a healthy recreational water activities. system.

Upper Economic: The Upper Barwon River Adequate water quality, depth and Where possible, environmental Barwon Stock and predominantly flows through private connectivity is important to ensure watering supports a healthy, River domestic property which is sometimes used use as a water supply catchment. flowing and connected system with use for farming purposes. Landholders adequate depth and water quality have an interest in maintaining a to ensure economic values are healthy system. retained.

Corangamite Catchment Management Authority 17

Upper Barwon River Seasonal Watering Proposal 2021-22

4. Seasonal review 2020-21

4.1 Climate

The Barwon South West region has a temperate climate with mild to warm summers and cold winters. Summer average maximum temperatures are around 22 to 24°C near the coast and in elevated areas, and 25 to 27°C inland. Winter average maximum temperatures are around 12 to 14°C. Rainfall occurs mostly in winter and spring and is generally the result of rain-bearing weather systems coming from the west (BoM, 2021).

2020 was the fourth-warmest year on record for Australia, with the averaged mean temperature for the year 1.15 °C above the 1961-1990 average. Mean annual minimum temperatures were also above average and Australia experienced its warmest Spring on record in 2020. Victoria had close to average rainfall in 2020, with April being the third wettest on record, however most other months during the year were drier than average for most parts of the state.

Rainfall in the Upper Barwon was overall above average in 2020 (Figure 5), with 8 months of the year being wetter than average (2000-2019) and 4 months being drier, including July which was significantly below average. The August, September and October rainfall provided a natural winter fresh flow for the Barwon River (Figure 6), where the daily average stream flows in Winchelsea reached 1,465ML/day in late September and peaked higher again at 3,247 ML/day in early October. Flows petered out at the start of November and peaked again in January with record high rainfall of almost 200 mm falling in one day (Figure 5).

Corangamite Catchment Management Authority 18

Upper Barwon River Seasonal Watering Proposal 2021-22

Figure 5. A comparison of monthly average rainfall at Mount Sabine 2000-2019, 2020 & 2021

Figure 6. Daily average stream flow at Ricketts Marsh and Winchelsea, 2020-21

Corangamite Catchment Management Authority 19

Upper Barwon River Seasonal Watering Proposal 2021-22

4.2 Environmental water delivery 2020-21

Priorities for environmental flow delivery in 2020-21 were for dry season low flow and fresh releases down the east branch, followed by dry season low flow down the west.

In the context of significant rainfall maintaining flow, it was agreed with Barwon Water just before Christmas, to delay the start of releases down the east branch for one week initially, to allow repair of a faulty dam gauge. Continuing high rainfall, including a large rain event in early January continued to delay releases. Flow data from a new gauge on the east branch became available during the second week of January, and flows were commenced on January 18 down both the east and west branches which in total varied between 4-6ML/day. As CCMA became familiar with how natural flows down the east were being sustained by ongoing rainfall through a wet summer, all flow releases were switched to the west branch because flow recommendations were being met naturally on the east.

Dry period low flow releases down the east branch varied between 1 and 3 ML/d between January 18 and 29 and can be seen in Figures 7 and 8. Low flow releases down the west branch varied between 3 and 5 ML/d from January 18 onwards, with releases made exclusively down the west branch at a rate of 5 ML/d from January 30. There were no fresh releases made during the dry season, as these flow components were met naturally in the east branch as the result of rainfall, and there is insufficient environmental entitlement to make fresh releases down the west branch. There is no flow gauge currently available on the west branch so low flow releases down this branch have not been graphed, however the result of combined releases and natural flow can be measured further down-stream at Rickett’s Marsh (Figure 9) in reach 7.

Corangamite Catchment Management Authority 20

Upper Barwon River Seasonal Watering Proposal 2021-22

Figure 7. East branch flow against reach 4 flow recommendations in 2020-21

Corangamite Catchment Management Authority 21

Upper Barwon River Seasonal Watering Proposal 2021-22

Figure 8. Dry period east branch flow against reach 4 flow recommendations in 2020-21

Corangamite Catchment Management Authority 22

Upper Barwon River Seasonal Watering Proposal 2021-22

Figure 9. Daily average stream flow at Ricketts Marsh and flow recommendations achieved

Corangamite Catchment Management Authority 23

Upper Barwon River Seasonal Watering Proposal 2021-22

4.3 Hydrological achievement

Water monitoring gauges can be used to assess whether releases from the West Barwon reservoir are meeting environmental flow recommendations downstream and are used to monitor compliance and inform planning and delivery. The Upper Barwon system does not have a formal compliance point as yet, because operating arrangements and a metering program for this system are still being drafted by VEWH in consultation with Barwon Water and CCMA. Historically, monitoring of flow compliance for environmental watering on the east branch has been assessed via flow rate data provided by Barwon Water immediately downstream of the Upper Barwon east branch release point. In 2020 the King Ck Junction gauge was installed on the east branch. This gauge will be used in the future to assess flow delivery against recommendations in the east branch. Flow compliance in reach 7 will continue to be monitored through the Rickett’s Marsh gauge, just downstream of Birregurra. It is expected that one or both of these gauges may be formalised as compliance points when the Operating Arrangements and Metering Program is finalised in 2021.

East branch recommendations were met naturally through a wet summer. In the west branch, although low flow releases were made, the release volumes were insufficient to have met flow recommendations in this reach, particularly in the context of the on-stream West Barwon Reservoir preventing natural flow peaks (noting that there is no gauge on this branch) . Although no environmental water was delivered over the wet period (June to November), compliance below the confluence of the east and west branches at Ricketts Marsh was achieved naturally for the wet period freshes and winter baseflow was partially met approximately 78% of the time. At the end of October, the flow dropped off at Ricketts Marsh compared to the previous months. A downpour in January resulted in a partial dry period fresh that exceeded the recommended level of 230ML/day over four days. The peak was 464 ML/day, however it fell short in duration by 1 day. Environmental releases for 2022-21 are presented in Figures 8,9 and 10. Flow compliance for the current and previous years as measured at gauging points available is summarised in Tables 6 (reach 7 - Ricketts Marsh) and 7 (reach 4 – East Barwon River at flume) below.

Table 6 shows that over the past decade, the summer low flows and freshes have not been met at Rickett’s Marsh, although a small partial achievement of all summer components this year was assisted by environmental releases. Small winter freshes often occur naturally, and the natural flows managed to fulfil the winter base flow 70% of the time.

It should be noted that compliance for 2009-10 to 2017-18 was assessed against flow recommendations for Reach 1: Upper Barwon River from the old FLOWS study (Lloyd, 2006), and

Corangamite Catchment Management Authority 24

Upper Barwon River Seasonal Watering Proposal 2021-22 during this time there was no environmental entitlement. The last three years have been assessed against the new flow recommendations for Reach 7: Barwon River downstream of Boundary Creek from the updated FLOWS study update (Alluvium, 2021).

Table 7 introduces a check point for Reach 4: Upper Barwon east, adapted from stream flow measurements collected by Barwon Water at the top of the east branch and the new King Ck Junction gauge. Both dry period flow components were achieved, and two wet period components were partially achieved in 2020-21 for Upper Barwon east. However, the year is not over and there is still a small window of opportunity for wet period freshes be completely fulfilled in 2021.

Corangamite Catchment Management Authority 25

Upper Barwon River Seasonal Watering Proposal 2021-22

Table 6. Hydrological achievement of flow compliance over time at Ricketts Marsh (Conns Lane, Birregurra): 2009-2021 Flow Hydrological achievement of flow components over time Ecological outcomes/observations relating to the Compon 2009/10 to 2020/21 achievement of PWA in 2020-21 ent Flow component 18- 19- 20- (Lloyd, (FLOWS, 2021) 19 20 21

2006) for Reach 7:

for Reach Barwon River

10 11 12 13 14 15 16 17 18

------1: Upper - D/S of Boundary

Barwon Creek.

2010 2011 2012 2013 2014 2015 2016 2017 River 2009 Summer Dry period low E E EO Summer low flow supplemented, approx. 25% compliance low flow flow since Dec 1 (as of 24/02/21).

Summer Dry period fresh E U UO One event (Jan 2021) partially met (naturally), volume low flow exceeded rec (peak of 464ML/d), however 1 day short. freshes

Winter Wet period low U U UO Winter base flow was partially met, approximately 78% of the baseflow flow time.

Winter Wet period fresh U U UO Three events (natural), all above recommended volume and small high two longer than recommended. flow fresh Large Bankfull U UO Early October for one day. In August there was a flow of 2,700 high flow ML/d which is not compliant as the recommended magnitude is fresh 3000 M, but should still be noted as it still would have achieved ecological outcomes.

No significant part of the flow component achieved E Managed environmental water release O Consumptive water en route/other managed flow (including passing flows) Flow component partially achieved U Unregulated (natural)

Flow component has been completely achieved, i.e., complete duration, X Unknown at this stage frequency and volume was achieved

Corangamite Catchment Management Authority 26

Upper Barwon River Seasonal Watering Proposal 2021-22

Table 7. Hydrological achievement of flows 2020-21 at the east branch (East Barwon River at Flume) Flow component (FLOWS, Hydrological achievement of flow components Reach 2021) Upper 19-20 20-21 Ecological outcomes/observations relating to the achievement of PWA in

Barwon 2020-21 east EO EO Flow achieved by a combination of environmental releases and passing/natural Dry period low flow branch flow. 0.5ML/d OU Environmental water was not required as 2 fresh events achieved naturally, both Dry period fresh at the start of January. They exceeded the recommended volume substantially, 35ML/d peaking at approximately 218 ML/day on the 5th of January. Wet period low flow OU Achieved 81% of the time naturally. 10ML/d Wet period fresh OU Three events that reached the recommended volume but fell short in duration 160ML/d (August & September). Bankfull Largest volume recorded was 218ML/day in January. 800ML/d

No significant part of the flow component achieved Flow component partially achieved Flow component has been completely achieved, i.e., complete duration, frequency and volume was achieved E Managed environmental water release O Consumptive water en route/other managed flow (including passing flows) U Unregulated (natural) X Unknown at this stage

Corangamite Catchment Management Authority 27

Upper Barwon River Seasonal Watering Proposal 2021-22

4.4 Key ecological observations

The local community reported that platypuses were sited on multiple occasions at an area called ‘The Meadow’ at Birregurra over December and January, and crayfish holes were observable on the river flat near Main Road after flooding.

In 2020, Stage 6 of the Victorian Environmental Flows Monitoring and Evaluation Program (VEFMAP) led by the Arthur Rylah Institute (ARI) identified some of the patterns associated with fish responses to environmental flows across Victoria. Stage 6 is now complete, and Stage 7 will also look at how changing spring flow pulses and baseflow recommendations may affect fish retention and survival.

Stage 6 of VEFMAP identified some emerging patterns from environmental watering in Victoria (see Table 8). The VEFMAP program does not cover all systems comprehensively in the state where environmental water is delivered. Representative systems are chosen for monitoring and assessment, with assumptions then made about similar systems such as the Upper Barwon. Therefore, this information has been included and its relevance to the Upper Barwon River is addressed below. The CCMA will continue to seek funding from investment sources for ecological monitoring and observation resources.

Table 8. Identified emerging patterns in environmental watering in Victoria and their relation to the Upper Barwon ARI observations Upper Barwon consideration Given that high discharge rates in early spring increase the This is not relevant to Upper number of galaxiids in rivers, spring environmental flow Barwon system as there is releases are not expected to provide detectable benefits at insufficient entitlement to provide the population scale within rivers when a large natural flow spring releases. pulse has already occurred during spring. These environmental flow releases are best used in years with relatively low spring discharge (e.g. Werribee River in 2017). To provide conditions for upstream dispersal, instream Dry season base flow in the east habitat and survival of galaxiids and Tupong, maintain recent branch is the priority watering base flow targets that have been shown to provide enough action, given fish dispersal is not depth for the upstream migration and sustain suitable water blocked by the reservoir wall. quality for galaxiids and Tupong. Consider prioritising summer or early autumn freshes to Summer or early autumn freshes provide connectivity for large-bodied species or, during high are already prioritised according to recruitment years (e.g. years with high spring flows for the FLOWS study; however, flow galaxiids), to enhance the upstream dispersal of juvenile constrictions and the limited nature

Corangamite Catchment Management Authority 28

Upper Barwon River Seasonal Watering Proposal 2021-22

ARI observations Upper Barwon consideration diadromous fishes. However, sufficient base flows are of the entitlement mean that fresh considered a priority. releases will have limited effect on juvenile diadromous fishes in the middle to lower reaches.

Environmental base flows and fresh releases will not benefit See comments above. This is also upstream dispersal of diadromous fishes in rivers where noted in the FLOWS study. CCMA barriers (natural or artificial) prevent their movement. has a program of prioritised fish barrier removal throughout the Barwon-Moorabool system.

4.5 Shared benefit review

This section should be read in conjunction with section 3.1 which outlines how stakeholders’ values are considered wherever possible in the environmental delivery of water. Table 9 provides more detail where benefits are general in nature and linked to the overall watering activities, and of specific outcomes achieved in 2020-21 water year, where they exist. The CCMA is flexible in its delivery approach and aspires to achieve shared benefit opportunities that arise from the delivery and use of environmental water. Wherever possible, CCMA times releases to coincide with long weekends and school holidays.

As the environmental entitlement is small, the increased flow down the upper reaches of the Barwon is small and mainly experienced through private farming properties. One community member stated that the river at Birregurra was quite extensively used for swimming in January and February. Further specific shared benefits were not reported, however assumptions can be made that active and passive recreation benefits would occur downstream through the provision of water in the river, such as recreational fishing and walking.

Corangamite Catchment Management Authority 29

Upper Barwon River Seasonal Watering Proposal 2021-22

Table 9. Shared benefits review Beneficiary Review of benefits / outcomes Traditional Traditional Owner wellbeing is closely tied to healthy Country. Owners Environmental flows that support and improve the health of the Upper Barwon River may therefore benefit Traditional Owners. Values include maintaining healthy, thriving culturally significant species. Several of the cultural values and objectives as outlined in 5 for the Wadawurrung were supported in the 2020-21 watering year as a result of natural rainfall and the release of environmental flow, however it should be noted that the ability of the current releases to influence values on Wadawurrung Country is limited due to the small volume of the entitlement. These values include maintaining and improving the abundance of culturally significant species such as Wad-dirring/Perridak (Platypus), Bunyia (Eels), Turrpurt (native trout galaxias spp, Ware-rap (Blackfish), Polango Warngare (water ribbons Triglochin procera, Tark (common reed Phragmites australis, Toolim (Pale Rush Juncus pallidus), Bal-yan (Cumbungi Typha latifolia) and maintaining deep pools and confluences.

Landholders Low flow releases and freshes that are delivered throughout the dry period help to prevent declines in water quality, potentially improving quality of supply for landholders who use the water for stock and domestic purposes. Environmental water may have assisted with maintaining a level of flow that mitigates invasive terrestrial vegetation intruding the channel, which would cause constrictions and impact negatively on the landholder’s property as it could potentially cause flooding.

Recreational The dry period low flow released throughout summer and autumn in both users/environment the east and west branches would have had a subtle freshening impact groups/local which may have improved water quality and connectivity. This may have businesses benefited passive recreation for those participating in swimming, kayaking, bushwalking, camping or fishing. It was reported that the section of the river that flows through Birregurra was a popular swimming spot over summer. A member of community reported multiple platypus and crayfish hole sightings, serving aesthetic and intrinsic benefits.

Corangamite Catchment Management Authority 30

Upper Barwon River Seasonal Watering Proposal 2021-22

5. Environmental objectives and scope of environmental watering

“To improve the Barwon River’s flow-dependent ecological values and services through the

provision of environmental water. The delivery of environmental water will also provide for social

and cultural values for future generations.” (UBSWAG endorsed long-term watering objective for

the Upper Barwon, 2017).

Figure 10. Flow recommendations for the Barwon River

Corangamite Catchment Management Authority 31

Upper Barwon River Seasonal Watering Proposal 2021-22

5.1 Water delivery objectives

The FLOWS study update (Alluvium 2021) highlights that the volume of water in the environmental entitlement is insufficient to meet all the recommended flow components identified (Figure 10), and sets prioritised targets for water recovery to maintain and improve flow-dependent ecological values into the future.

An overview of the reaches of the Barwon River, that are situated downstream of the West Barwon Reservoir and can therefore be influenced by the entitlement, are presented in Table 10. The priority of each reach is also presented.

Table 10. Environmental watering priorities and the Upper Barwon entitlement beneficiaries Ability of Reach Reach Name Priority entitlement to No. influence Upper Barwon west (u/s Moderate (as a means to get more 3 High Boundary Creek) water for reaches 9 & 10). 4 Upper Barwon east High High

Barwon River (d/s 7 Not assigned in FLOWS study. Medium Boundary Creek) 9 Winchelsea Highest Minor

10 Lower Barwon Highest Minor

The current environmental entitlement falls well short of the volume required to meet recommended flow components for all branches, and the physical location of the entitlement only allows provision of environmental water to the Upper Barwon east and west branches, and to a lesser extent the reaches immediately downstream, with diminishing effect. Water can reach the township of Winchelsea, however the river is prone to drying out, particularly downstream of Winchelsea before the Leigh River enters the system.

With the limited entitlement, the CCMA will deliver the water available down the Upper Barwon east as a priority, then down the Upper Barwon west in order to deliver water through to priority reaches 7, 9 located downstream. Delivery peaks will be modified to prevent flooding due to channel constricting weed infestations. Delivery of this water will assist in supporting the environmental objectives defined in the FLOWS study update (Alluvium 2021).

Corangamite Catchment Management Authority 32

Upper Barwon River Seasonal Watering Proposal 2021-22

The environmental objectives are as follows; • Maintain or improve abundance, breeding and recruitment of migratory fish • Maintain or improve abundance, breeding and recruitment breeding and recruitment of resident non-migratory fish • Maintain or improve abundance, breeding and recruitment of macroinvertebrates as a food source for fish, frog and platypus populations • Maintain or improve abundance, breeding and recruitment of growling grass frog • Improve condition and extent of growling grass frog • Maintain or improve, abundance, condition and extent of platypus • Maintain or improve condition, extent and diversity of in-stream, emergent, riparian and floodplain vegetation.

Delivery of environmental water also helps to improve and maintain good water quality and channel form.

Helping to guide the prioritisation of environmental watering, key cultural objectives identified by the Wadawurrung for the reaches of the Barwon River that flow through Country downstream of Winchelsea can be found in section 3.1 Aboriginal cultural values and uses of waterways.

It should be noted that the CCMA continues to work to build the case for more water in the Barwon River though projects such as the ‘Analysis of the social and economic values dependent on a flowing Barwon River through Geelong and lower Moorabool River’, which is currently underway. CCMA are also engaged in the DELWP led project of preparing the new Central and Gippsland Regions Sustainable Water Strategy (SWS) and would encourage the community to do the same through the DELWP community consultation. The CCMA also plans to work on managing points of constriction out of the system over time to allow flow releases to match FLOWS recommendations, but in the short- term flow releases will need to be modified.

5.2 Flow recommendations and potential watering actions

The FLOWS study update (Alluvium 2021) recommends a flow regime for the Upper Barwon River, consisting of a number of flow components to be delivered at specific flow rates and frequencies. These are the basis for the potential watering actions in any given year.

Potential watering actions produce an ‘expected watering effect’ in the river that will help to achieve an environmental objective. The ‘expected watering effects’ relate to physical, chemical, biological or behavioural responses to specific components of the watering regime. Environmental objectives,

Corangamite Catchment Management Authority 33

Upper Barwon River Seasonal Watering Proposal 2021-22

such as ‘Maintain or improve abundance, breeding and recruitment of migratory fish’, are measurable outcomes that are not solely linked to environmental watering and are often achieved through a range of complementary management activities, such as instream and riparian improvements (See Section 8 Confounding Factors).

Flow prioritisation is an important part of flow delivery planning for the Upper Barwon River due to the limited amount of water available within the entitlement and to ensure the water is used for the greatest environmental benefit. The FLOWS study update (Alluvium 2021) was developed to determine the volume, priority and ecological objectives for flow components in the Barwon River under different climatic scenarios. It prioritises flows in the following order, with flows in the east branch prioritised over the west: 1. provision of dry season low flows 2. provision of dry season freshes 3. provision of wet season freshes 4. provision of wet season low flow

Whilst the FLOWS study update (Alluvium 2021) recommends delivering all the Upper Barwon east branch flow recommendations before putting water down the west, these priorities are a trade-off, particularly considering the flow volume limitations of the Upper Barwon east branch preventing delivery of wet period freshes, bank full and overbank recommendations; the exception being the ability to supplement wet period low flow. On balance, provision of water down both upper branches in the dry period has been prioritised as the only practicable option.

The potential watering actions for the coming water year are detailed below in Table 11. The table reflects the potential watering actions in order from highest to lowest priority. It is expected that with an average year forecast and the limited entitlement there will only be enough water for priorities 1 and 2, with some water available for priority 3. However, some flow components, such as winter base flows, are likely to be partially achieved through rainfall. If climate conditions change as the water year progresses, flow planning may be amended to reflect revised water availability. In the table below the letters next to expected watering effects indicate which environmental objective that watering effect contributes to.

Corangamite Catchment Management Authority 34

Upper Barwon River Seasonal Watering Proposal 2021-22

Table 11. Potential watering actions for 2021-22 Potential Priority 1: Dry period low flow (Dec-May 0.5-5ML/d) – East branch/ reach 4 watering action Expected • Provide water in pools for habitat and food sources (C) watering effects • Provide pool habitat (K) • Maintain adequate depth of permanent water in channel (M) • Maintain adequate depth of permanent water in stream channel to limit terrestrial encroachment into aquatic habitats (N) • Maintain a shallow water table with low salinity throughout the year (P) Environmental • C. Maintain abundance of resident freshwater fish, including galaxias, objectives smelt, big-headed gudgeon and Yarra pygmy perch. • K. Maintain abundance of platypus • M. Maintain or improve condition and extent of instream vegetation to provide structural habitat for macroinvertebrates and various fish species. • N. Maintain or improve condition, extent, and diversity of emergent macrophyte vegetation to provide structural habitat and channel/lower bank stability to low and moderate flows. • P. Maintain or improve condition and extent of floodplain vegetation as part of endangered EVCs. Application of Magnitude (ML) Duration Frequency Timing potential (days) (per year) (months) watering action in 2021-22 Dry 0.5-5 or natural Continuous Continuous Dec to May Average 0.5-5 or natural Continuous Continuous Dec to May Wet 0.5-5 or natural Continuous Continuous Dec to May Rationale for This flow is required for the survival of high value species; to provide essential proposed habitat for aquatic fauna; and to provide moisture to instream and emergent application in macrophyte vegetation. The water entitlement must be delivered down the 2021-22 Upper Barwon east or Upper Barwon west branches, and the Upper Barwon east branch has been identified as the higher priority. Dry period low flow is the highest flow priority. A flow range up to 5ML/d has been proposed to achieve an average of the recommended flow of 0.5ML/day.

Corangamite Catchment Management Authority 35

Upper Barwon River Seasonal Watering Proposal 2021-22

Potential Priority 2: Dry period freshes (Dec-May 9-35ML/d for 2 days x 2) – East watering action branch/ reach 4 Expected • Provide water over riffles to allow fish to move between pools to breed, watering effects feed and find new habitats (C) • Submerge and clean woody debris and hard surfaces to provide breeding substrate (D) • Sustain macroinvertebrate communities during the dry period (F) • Provide longitudinal connectivity between reaches (L) • Provide a mosaic of spatially and temporally differentially wetted areas within stream channel, on benches and on lower banks (N) • Support growth on terraces, channel edge and lower bank (N), (O) • Provide minimum velocity to establish mixing and flushing of pools (Q) • Scour sediment from base of pools to maintain pool and to use bed sediments to scour algae from riffles (R) • Mobilise sediment from base of pools (S) Environmental • C. Maintain abundance of resident freshwater fish, including galaxias, objectives smelt, big-headed gudgeon and Yarra pygmy perch. • D. Improve breeding and recruitment of resident freshwater fish including River blackfish. • F. Maintain abundance of macroinvertebrates as a food source for fish, frog and platypus populations. • L. Improve condition and extent of platypus. • N. Maintain or improve condition, extent, and diversity of emergent macrophyte vegetation to provide structural habitat and channel/lower bank stability to low and moderate flows. • O. Maintain or improve condition, extent, and diversity of riparian vegetation as part of endangered Ecological Vegetation Class (EVC). • Q. Reduce prolonged stratified conditions in pools and promote adequate levels of water quality to allow fish and macroinvertebrate populations to persist. • R. Improve and maintain abundance and condition of pools, large wood and riffles to provide structural habitat for macroinvertebrates and various fish species. • S. Maintain channel capacity, shape and form to support flora and fauna values and objectives. Application of Magnitude (ML) Duration Frequency Timing potential (days) (per year) (months) watering action in 2021-22 Dry 35 (9-15) 2 2 Dec to May Average 35 (9-15) 2 2 Dec to May Wet 35 (9-15) 2 3 Dec to May Rationale for These freshes provide flushes that assist in maintaining adequate water proposed quality and the opportunities for migration of fish and other fauna. Without application in these freshes, there is the potential for regional extinction and many species 2021-22 will not be able to move to new habitats and reproduce. Flow constrictions in the Upper Barwon branch will only allow delivery of less than 35ML/d to prevent localised flooding. Peak fresh volumes will be modified based on delivery experience gained from the 2019-20 and 2020-21 water years and ‘real time’ local knowledge around constriction impacts and management.

Corangamite Catchment Management Authority 36

Upper Barwon River Seasonal Watering Proposal 2021-22

Potential Priority 3: Dry period low flow (Dec-May, up to 30ML/d, as water availability watering permits) – West branch/ reach 3 action Expected • Provide water in pools for habitat and food sources (C) watering • Provide pool habitat (K) effects • Maintain adequate depth of permanent water in channel (M) • Maintain adequate depth of permanent water in stream channel to limit terrestrial encroachment into aquatic habitats (N) • Maintain a shallow water table with low salinity groundwater throughout the year (P) • Provide minimum velocity to maintain mixing in pool (Q) Environmental • A. Maintain abundance of migratory fish including short-finned eels, objectives Australian grayling, and tupong. • C. Maintain abundance of resident freshwater fish, including galaxias, smelt, big-headed gudgeon and Yarra pygmy perch. • M. Maintain or improve condition and extent of instream vegetation to provide structural habitat for macroinvertebrates and various fish species. • N. Maintain or improve condition, extent, and diversity of emergent macrophyte vegetation to provide structural habitat and channel/lower bank stability to low and moderate flows. • P. Maintain or improve condition and extent of floodplain vegetation as part of endangered EVCs. • Q. Reduce prolonged stratified conditions in pools and promote adequate levels of water quality to allow fish and macroinvertebrate populations to persist. Application of Magnitude (ML) Duration Frequency Timing potential (days) (per year) (months) watering action in 2021- Dry Up to 30 or natural Continuous Continuous Dec to May 22 (likely to be 2-4) Average Up to 30 or natural Continuous Continuous Dec to May (likely to be 2-4) Wet Up to 30 or natural Continuous Continuous Dec to May (likely to be 2-4) Rationale for As mentioned above, low flows are required for the survival of high value proposed species, to provide essential habitat for aquatic fauna and to provide moisture to application in instream and emergent macrophyte vegetation. While the next priority in the 2021-22 FLOWS study is wet period freshes, such freshes cannot be delivered down the Upper Barwon east branch due to flow constrictions. It has therefore been decided that delivering dry period low flow down the Upper Barwon west branch should be the next priority. This can be done at the recommended rate of 30ML/d depending on water availability, which makes it likely to be delivered at a much lower rate (due to the small entitlement) but combined with the flow down the Upper Barwon east will help deliver more of this top priority component to the higher priority Winchelsea reach downstream.

Corangamite Catchment Management Authority 37

Upper Barwon River Seasonal Watering Proposal 2021-22

Potential Priority 4: Wet period low flow (June-Nov, 10ML/d or natural)– East branch/ watering reach 4 action Expected • Provide connectivity to allow fish to migrate downstream to breed (B) watering • Provide prolonged seasonal inundation of vegetation beds and instream effects benches as habitat to stimulate invertebrate hatching and fish breeding (E) • Create and extend aquatic habitats for macroinvertebrates (F) • Allow growth and reproduction of macroinvertebrate communities (G) • Provide a mosaic of spatially and temporally differentially wetted areas within stream channel, on benches and on lower banks (N) • Support growth on terraces, channel edge and lower bank (O) • Scour sediment from base of pools to maintain pool and to use bed sediments to scour algae from riffles (R) • Maintain volume and size of transported sediments (S) Environmental • B. Improve breeding and recruitment of migratory fish including broad finned objectives galaxias and common Jollytail. • E. Improve breeding and recruitment of resident freshwater fish, including galaxias, smelt, big-headed gudgeon, and Yarra pygmy perch. • F. Maintain abundance of macroinvertebrates as a food source for fish, frog and platypus populations. • G. Improve breeding and recruitment of macroinvertebrates as a food source for fish, frog and platypus populations. • N. Maintain or improve condition, extent, and diversity of emergent macrophyte vegetation to provide structural habitat and channel/lower bank stability to low and moderate flows. • O. Maintain or improve condition, extent, and diversity of riparian vegetation as part of endangered Ecological Vegetation Class (EVC). • R. Improve and maintain abundance and condition of pools, large wood and riffles to provide structural habitat for macroinvertebrates and various fish species. • S. Maintain channel capacity, shape and form to support flora and fauna values and objectives. Application of Magnitude (ML) Duration Frequency Timing potential (days) (per year) (months) watering action in 2021- Dry 10 or natural Continuous Continuous June to Nov 22 Average 10 or natural Continuous Continuous June to Nov Wet 10 or natural Continuous Continuous June to Nov Rationale for These flows play an important role in channel shape and form over long time proposed scales. Failure to provide these flows over long periods of time may result in application in reduction of available habitat due to deposition of material in pools and other 2021-22 changes in channel form. Wet period low flow is the next priority after dry period low flow; dry period freshes which can be delivered (albeit modified); and wet period freshes which cannot be delivered due to water and flow volume constraints. This flow component can be delivered at the recommended volume if water becomes available or higher priorities are met naturally. Due to the fact that this priority watering action is recommended at the start of a water year it makes it difficult to deliver as it is a lower priority than those that come after it, especially considering that the higher priority watering actions may exhaust the entitlement.

Corangamite Catchment Management Authority 38

Upper Barwon River Seasonal Watering Proposal 2021-22

Potential Priority 5: Dry period fresh (Dec-May modified from 100ML/d to ~50ML/d for 6 watering days x5)– West branch/ reach 3 action Expected • Provide water over riffles to allow fish to migrate upstream from estuary (A) watering • Provide water over riffles to allow fish to move between pools to breed, feed and effects find new habitats (C) • Submerge and clean woody debris and hard surfaces to provide breeding substrate (D) • Sustain macroinvertebrate communities during the dry period (F) • Provide longitudinal connectivity between reaches (L) • Provide a mosaic of spatially and temporally differentially wetted areas within stream channel, on benches and on lower banks (N) • Support growth on terraces, channel edge and lower bank (N), (O) • Provide minimum velocity to establish mixing and flushing of pools (Q) • Scour sediment from base of pools to maintain pool and to use bed sediments to scour algae from riffles (R) • Mobilise sediment from base of pools (S)

Environmental • A. Maintain abundance of migratory fish including short-finned eels, Australian objectives grayling, and tupong. • C. Maintain abundance of resident freshwater fish, including galaxias, smelt, big- headed gudgeon and Yarra pygmy perch. • D. Improve breeding and recruitment of resident freshwater fish including River blackfish. • F. Maintain abundance of macroinvertebrates as a food source for fish, frog and platypus populations. • L. Improve condition and extent of platypus. • N. Maintain or improve condition, extent, and diversity of emergent macrophyte vegetation to provide structural habitat and channel/lower bank stability to low and moderate flows. • O. Maintain or improve condition, extent, and diversity of riparian vegetation as part of endangered Ecological Vegetation Class (EVC). • Q. Reduce prolonged stratified conditions in pools and promote adequate levels of water quality to allow fish and macroinvertebrate populations to persist. • R. Improve and maintain abundance and condition of pools, large wood and riffles to provide structural habitat for macroinvertebrates and various fish species. • S. Maintain channel capacity, shape and form to support flora and fauna values and objectives. Application of Magnitude (ML) Duration Frequency Timing potential (days) (per year) (months) watering action in 2021- Dry 100 6 5 Dec to May 22 Average 100 6 5 Dec to May Wet 100 8 6 Dec to May Rationale for As above, after all the flow components that can be physically delivered down the proposed Upper Barwon east have been achieved, the next priority is to target a dry period application in fresh down the Upper Barwon west branch following a dry period low flow. 2021-22 These freshes provide flushes that assist in maintaining adequate water quality and the opportunities for migration of fish and other fauna. Without these freshes, there is the potential for regional extinction and many species will not be able to move to new habitats and reproduce.

Corangamite Catchment Management Authority 39

Upper Barwon River Seasonal Watering Proposal 2021-22

Potential Priority 6: Wet period low flow (June-Nov) modified from 100 ml/d to watering 50ML/day)– West branch/ reach 3 action Expected • Mobilise sediment from base of pools for sustained duration (S) watering • Provide water in pools for habitat and food sources (A), (C) effects • Provide pool habitat (K) • Maintain adequate depth of permanent water in the channel, with natural seasonal drawdown to promote recruitment (M) • Maintain adequate depth of permanent water in stream channel to limit terrestrial encroachment into aquatic habitats (N) • Maintain a shallow water table with low salinity groundwater throughout the year (P) • Provide minimum velocity to maintain mixing in pool (Q)

Environmental • S. Maintain channel capacity, shape and form to support flora and fauna objectives values and objectives. • A. Maintain abundance of migratory fish including short-finned eels, Australian grayling and tupong. • C. Maintain abundance of resident freshwater fish, including galaxias, smelt, big-headed gudgeon and Yarra Pygmy perch. • K. Maintain abundance of platypus. M. Maintain or improve condition and extent of instream vegetation to provide structural habitat for macroinvertebrates and various fish species. • N. Maintain or improve condition, extent and diversity of emergent macrophyte vegetation to provide structural habitat and channel/lower bank stability to low and moderate flows. • P. Maintain or improve condition and extent of floodplain vegetation as part of endangered EVCs. • Q. Reduce prolonged stratified conditions in pools and promote adequate levels of water quality to allow fish and macroinvertebrate populations to persist. Application of Magnitude (ML) Duration Frequency Timing potential (days) (per year) (months) watering action in 2021- Dry 100 or natural (50) Continuous Continuous June to Nov 22 Average 100 or natural (50) Continuous Continuous June to Nov Wet 100 or natural (50) Continuous Continuous June to Nov Rationale for As mentioned above, these flows play an important role in channel shape and proposed form over long time scales. Failure to provide these flows over long periods of application in time may result in reduction of available habitat due to deposition of material in 2021-22 pools and other changes in channel form. While the next flow component priority after dry period freshes is wet period freshes, they are not required in a dry year (as forecast), and are undeliverable at anywhere near the recommended volume, with the current restrictions. Wet period low flow is therefore the next priority and can be achieved in a modified form if the water is available.

Corangamite Catchment Management Authority 40

Upper Barwon River Seasonal Watering Proposal 2021-22

6. Scenario Planning

6.1 Outlook for 2021-22

The Barwon South West region has a temperate climate, with mild to warm summers and cold winters. Summer average maximum temperatures are around 22 to 24°C near the coast and in elevated areas, and 25 to 27°C inland. Winter average maximum temperatures are around 12 to 14°C. Rainfall occurs mostly in winter and spring and is generally the result of rain-bearing weather systems coming from the west (DELWP, 2015).

Australia’s temperature and rainfall variability are influenced by global warming caused by human activities, with the nation’s climate warming by around 1.44 °C since 1910 (Bureau of Meteorology, 2021). In 2021, the BOM predicts February to April is likely to be wetter than average for much of Australia. Whilst the outlook indicates wetter than average conditions, the southern part of Australia is in its drier season, therefore even if rainfall is above average it is not likely to be enough to relieve long-term rainfall deficits. Additionally, mean minimum temperatures are very likely (more than 80%) to be higher than the long-term mean. The 2020– 21 La Niña is nearing its end, with most oceanic indicators of the ENSO now at neutral levels. While around 40% of past La Niña events have re-strengthened for a second year, there are currently no models suggesting that La Niña will return during winter.

In this context, the FLOWS study update (Alluvium 2021) recommendations for the Upper Barwon will be in line with an ‘average conditions regime’ and watering actions prioritised based on the available entitlement. Regular monitoring of water levels and discharge through DELWP’s Water Measurement Information System (WMIS) and field observations will be important to determine the best time to release and in what volume. Even in wetter years, monitoring is important to determine how flows generated from natural rainfall events are meeting the flow recommendations for the river, and allow flow planning to be adapted accordingly.

6.2 Scenario planning

Planning for this year’s environmental watering has been tailored to average rainfall conditions but may be adapted if conditions change. The average year scenario has been highlighted in Table 12 below, which outlines how achievement of priorities may change under a range of resource availability and climate scenarios. In the driest scenarios the priority is to avoid critical losses or catastrophic events, while in wetter years the priority is to maximise recruitment and maintain geomorphic processes.

Corangamite Catchment Management Authority 41

Upper Barwon River Seasonal Watering Proposal 2021-22

The analysis of hydrological compliance over recent years (Section 4), shows a shortage of water availability especially over the dry months. Depending on climatic conditions it is expected that if available, the entire 1,000ML will be delivered over this dry period, which means wet period flows being reliant on rainfall events. There will be an increased capacity to meet a larger number of priority flow components in wetter years as more elements will be met by naturally occurring flows. Because the current entitlement only secures a fraction of the river’s water requirements, the achievement of environmental flow components is largely dependent on the prevailing climate during the 2021-22 water year.

Corangamite Catchment Management Authority 42

Upper Barwon River Seasonal Watering Proposal 2021-22

Table 12. Planning of environmental watering under different climate scenarios UPPER BARWON Drought Dry Average (predicted) Wet Expected availability No flow at Ricketts Marsh for six No flow at Ricketts Marsh for Low flow at Ricketts Marsh for two High flows throughout winter of environmental months Dec - May. four months Jan - April months Feb-March with very high peak flows and water Only the drought reserve available 20% reduction of water constant steady flow throughout (500ML) No carry over available. available. Planned use of No reduction of water availability. summer Planned use of allocation in West allocation in West Barwon Planned use of allocation in in West No reduction of water Barwon Reservoir = 250ML (half Reservoir =~ 300ML (above Barwon Reservoir = 500ML (above availability. Planned use of of drought reserve). Plus drought reserve of 500ML). drought reserve of 500ML). Plus allocation in West Barwon passing flows and rainfall. Plus passing flows and rainfall. passing flows and rainfall. Reservoir = 1,500ML (above drought reserve of 500ML). Plus passing flows and rainfall. Expected river Disconnected pools in some parts Disconnected pools in some conditions (including of the system. Cease to flow Bankfull flows persistent parts during first half of the year. unregulated water, events. Low flow over summer, high peaks in throughout winter, overbank Cease to flow events. consumptive water, Disconnected refuge habitat winter months conditions in some parts during Disconnected refuge habitat etc.) pools. spring and autumn months. pools Deteriorating water quality. Logic for scenario Water delivery to maintain water The logic here is the same as for Under this scenario, flow compliance The logic here is the same as for quality in refuge habitat pools, in the drought scenario, but it is in the east branch can be maintained the average scenario, but the upper east branch only. Only assumed that we can release with a lower release again, due to a greater benefits can be provided enough water for some low flow low flow down the east at a wetter system. Most east branch to the upper west branch and provision in the east branch. lower rate because the system freshes can be achieved with the lower reaches due to greater will be slightly more wetted up water available, and assumptions volume of water available for than under a drought scenario. have been made with regards to the delivery and the likelihood of However, less water available contributions of passing flow and east branch flow components for delivery because delivery natural achievement based on being met naturally. won’t utilise the drought reserve. previous years. Provide carry over (for critical Provide carry over (for critical environmental needs the Provide carry over (for critical environmental needs the following year). environmental needs the following following year). year).

Corangamite Catchment Management Authority 43

Upper Barwon River Seasonal Watering Proposal 2021-22

UPPER BARWON Drought Dry Average (predicted) Wet Tier 1a Potential • Priority 1 – East branch dry • Priority 1 – East branch dry • Priority 1 – East branch dry • Priority 1 – East branch dry watering actions: period low flow 0.5-5 (may period low flow 0.5-5 (may period low flow 0.5-5 (may need period low flow 0.5-5 expected to be need up to 5 ML/day release need 2.5 ML/day release to 1.5 ML/day release to achieve (release 0 ML/day)- delivered in 2021-22 to achieve 0.5 ML/d in achieve 0.5 ML/d in 0.5 ML/d in channel) achieved naturally channel) – NB a 5 ML/d channel) - NB a 2 ML/d • Priority 2- East branch dry • Priority 2- East branch dry release would only last for ~ release would only last for ~ period freshes x 2 - 9-35 ML/d period freshes x 3 - 9-35 1.5 months, meaning a lower 4 months, meaning a lower (constraints allow <15 ML/day) ML/d (15) – achieved level or series of short level or series of short ML/day for 2 days. naturally. releases would need to be releases would need to be • Priority 3- West branch dry • Priority 3 –West branch– considered. considered. period low flow up to 30 ML/day dry period low flow (partial. Approx. 0.5 ML/d) (modified volume about 8 ML/day)

Tier 1a environmental 250 ML (half of drought reserve) 300 ML (800ML including 500 ML (1000Ml including 500 ML 1500 ML (2000 ML including water demand drought reserve) drought reserve) 500 ML drought reserve)

Corangamite Catchment Management Authority 44

Upper Barwon River Seasonal Watering Proposal 2021-22

UPPER BARWON Drought Dry Average (predicted) Wet Tier 1b Potential • Priority 1 – but full • Priority 1 – but full • Priority 3- West branch dry • Priority 3- The remainder of watering actions: compliance (see above) compliance (see above) period low flow up to 30 ML/day – West branch dry period low delivery is reliant on • Priority 2- East branch dry • Priority 2- East branch dry but full compliance (see above) flow up to 30 ML/day – but additional period freshes x 2 - 9-35 period freshes x 2 - 9-35 • Priority 4- East branch wet full compliance (see above) water/resources ML/d (constraints allow <15 ML/d (constraints allow <15 period low flow 10 ML/day • Priority 4- East branch wet becoming available in ML/day) ML/day for 2 days ML/day) ML/day for 2 days • Priority 5- West branch dry period low flow 10 ML/day 2021-22 • Priority 3- West branch dry • Priority 3- West branch dry period fresh (modified volume) 50 • Priority 5- West branch dry period low flow up to 30 period low flow up to 30 ML/day for 6 days x 5 period fresh (modified ML/day ML/day • Priority 6- West branch wet volume) 50 ML/day for 8 • Priority 4- East branch wet • Priority 4- East branch wet period low flow 50 ML/d (modified days x 6 period low flow 10 ML/day period low flow 10 ML/day volume) • Priority 6- West branch wet • Priority 5- West branch dry • Priority 5- West branch dry period low flow 50 ML/d period fresh (modified period fresh (modified (modified volume) volume) 50 ML/day for 6 days volume) 50 ML/day for 6 x 5 days x 5 • Priority 6- West branch wet • Priority 6- West branch wet period low flow 50 ML/d period low flow 50 ML/d (modified volume) (modified volume)

Tier 1b environmental 17,008 ML 16,547 ML 14,057 ML 12,337 ML water demand Potential NA (current physical constraints NA (current physical constraints NA (current physical constraints do NA (current physical constraints environmental do not allow for tier 2 watering do not allow for tier 2 watering not allow for tier 2 watering actions) do not allow for tier 2 watering watering – tier 2 actions) actions) actions) Tier 2 environmental NA NA NA NA water demand Priority carry over As much as possible up to 500ML 500ML 500ML 500ML requirement Beyond Tier 1 and 2 Water Demands: A water recovery target of 28.6GL/yr. from the West Barwon Reservoir would return the Barwon River environmental flows to within 70% of the natural flow regime.

*Water required to deliver all Tier 1a and Tier 1b demands at the volumes currently permitted by the infrastructure and channel constraints. It includes low flow year-round, and compromised summer freshes down both the east and west Upper Branches.

Corangamite Catchment Management Authority 45

Upper Barwon River Seasonal Watering Proposal 2021-22

7. Delivery constraints

7.1 Temporary constraints

There are minimal temporary delivery constraints in the Upper Barwon.

7.2 Systemic constraints

7.2.1 Flow constriction and diversion points

The FLOWS study update (Alluvium 2021) highlights that many complementary actions will be required to realise the full effectiveness of the environmental entitlement, in particular to release ‘fresh’ events. The dry period fresh flow peak for the east branch has been reduced from 35ML/day to 9- 15ML/day. The need for flow reduction has been demonstrated in the past two watering years where despite the flow rate being significantly reduced each season, some flooding was still experienced. The flooding appeared to be caused by in-channel flow constrictions such as choking Willows and Glyceria, and to a lesser extent, old channel diversions to restricting infrastructure points. See section 8.1 and 8.2 for more information.

7.2.2 Allocation

The FLOWS study update (Alluvium 2021) has recommended a water recovery target of 28.6GL for the Barwon River to get back to 70% of natural flow and meet ecological requirements. Therefore, the current allocation is significantly insufficient to meet the river’s health requirements.

The Upper Barwon Environmental Entitlement 2018 allows for a 2,000ML share of the total storage capacity of the West Barwon Reservoir and allows for storage of 3.8% of the flow into the reservoir, up to the 2,000ML. Modelling has shown that this will typically be about 1,000ML of water each year, but theoretically up to 2,000ML or more could be available if a portion of the stored allocation was used and the 2,000ML storage allocation refilled. CCMA will however aim to always keep approximately 500ML in storage in case of drought.

The Government has begun work on a new Central and Gippsland Sustainable Water Strategy. These documents are a key element for planning Victoria’s water resources well into the future and can be a vehicle for recovering more water for the environment. Sustainable water strategies identify and manage threats to the supply and the quality of a region’s water resources and identify ways to improve waterway health. The new Central and Gippsland Sustainable Water Strategy includes the Upper Barwon River and a draft report was released in 2020 (DELWP, 2020).

Corangamite Catchment Management Authority 46

Upper Barwon River Seasonal Watering Proposal 2021-22

7.2.3 Barwon Water delivery infrastructure limitations

As operators of the West Barwon Reservoir, Barwon Water reports that the maximum release capacity from the reservoir is 320ML/day down the Upper Barwon west branch and 140ML/d down the Upper Barwon east branch. This is not a systematic constraint at this point in time but may be in the future if remediation is undertaken along the Upper Barwon east and west branches to improve channel capacity, and additional water is recovered for environmental release.

Corangamite Catchment Management Authority 47

Upper Barwon River Seasonal Watering Proposal 2021-22

8. Confounding factors

Flow alteration is one of many factors that affect the environmental condition of the Upper Barwon and many environmental watering objectives will not be fully achieved unless other impacts are adequately addressed. In the Upper Barwon system, there are confounding factors that impact negatively on the river’s health that cannot be mitigated by the entitlement alone. Confounding factors can be resolved between agencies and other stakeholders.

8.1 Flow constrictions

Following review of the environmental flow requirements for the Upper Barwon, Yarrowee and Leigh Rivers (Alluvium, 2019), release of the first environmental flow caused some inundation of private properties. This flooding was caused by in-channel flow constrictions from invasive species such as Willow and Glyceria and historic channel diversions and infrastructure. These flow constrictions prevent optimal delivery of the entitlement through the east and west branches of the river and have forced CCMA to reduce the volumes of all flow components in these branches to avoid flooding. The desired resolution is for CCMA, the local community, adjacent landholders and other key stakeholders to work together to remediate the current flow restrictions to allow the entitlement to be adequately delivered. Scoping work as recently been completed to address this issue.

8.2 Riparian rehabilitation

Healthy land supports healthy waterways. Water quality, bank stability and habitat can decline due to a lack of adequate riparian vegetation surrounding the river channel. As many parts of the Barwon River run through agricultural properties, there can be a severe lack of healthy riparian vegetation in some areas and this negatively impacts on the river’s health. To mitigate these impacts, CCMA works directly with landholders to fence off the riparian zone to keep stock away from the waterway and replant and revitalise native vegetation. CCMA has completed 6 projects in the last four years with landholders that equates to 4.7 hectares of rehabilitation.

8.3 Fish barriers

In the Upper Barwon system, there are several barriers to fish passage. This includes weirs, dams and obsolete structures that limit fish migration. To mitigate these impacts, removal or modification will be required. CCMA along with other agencies will seek to remediate these barriers where funding and resources are available.

Corangamite Catchment Management Authority 48

Upper Barwon River Seasonal Watering Proposal 2021-22

9. Increasing knowledge

Increasing our knowledge and addressing priority knowledge gaps is an important part of managing risks associated with environmental water delivery. To this effect, the CMA regularly reviews knowledge needs to enable the organisation to plan for and deliver environmental water in adaptive and effective manner.

9.1 Knowledge gaps 9.1.1 Gauging

Until recently, there was insufficient water gauging on the Upper Barwon River to adequately assess how releases from the West Barwon Reservoir move down the river. A new gauge has been installed on the east branch near Forrest, however it can only record low flow events. Before this new gauge was installed, the nominal compliance point was Conn’s Lane, Ricketts Marsh – just downstream from Birregurra. This can record higher flows, however it is over 52 km downstream of the release point and does not differentiate between flows being delivered down the Upper Barwon east and west branches. The confluence of these branches is only 27.4km downstream of the release point.

Barwon Water has provided access to gauge data on the Upper Barwon east branch just down-stream of the release point for this reach, which has helped CCMA to assess compliance. Barwon Water will also be installing new gauges on the west branch and the main branch just below the confluence of the east and west branches. This will provide further opportunities for monitoring e-flows and refinement of releases.

CCMA is working collaboratively with Barwon Water to ensure the new gauges do not create any unnecessary barriers to fish migration.

9.1.2 Cold water pollution

There has been a question raised by the community about cold water pollution risks in relation to environmental releases from West Barwon Reservoir. The CCMA has sought expert advice, and this has included a statement that a much greater risk to environmental values is posed by a lack of water. The risks are outlined below: • There are only two offtake points in the West Barwon Reservoir and water needs to be one metre above the offtakes to use it; there are situations where releases can be taken from up to 12m deep.

Corangamite Catchment Management Authority 49

Upper Barwon River Seasonal Watering Proposal 2021-22

• CCMA and Barwon Water are aware of the risks to biota because of cold or anoxic releases and have formalised a requirement that environmental flows will always be released from the highest possible point in the reservoir for this reason. • The river branches are monitored upstream and downstream of the reservoir, but the data sets are limited. A review of the limited data set indicates that within one day, there is likely to be 3.5-4.5-degree difference between water that has not been stored in the reservoir and water that is released.

To address the potential risks the CCMA has:

• Worked with Barwon Water to undertake a monitoring program that will result in a larger, more accurate data set that considers seasonal variation and aspect. Monitoring is underway. • Use this to obtain expert advice on the significance of any temperature variation to downstream ecosystems.

Corangamite Catchment Management Authority 50

Upper Barwon River Seasonal Watering Proposal 2021-22

10. Risk management

A risk assessment has been undertaken for the 2021-22 season, with members from Barwon Water (BW), the VEWH, and the CCMA present.

This assessment identifies the risks associated with delivering water for the priority actions. Mitigation actions to reduce risks have been identified and should be undertaken as part of the release plan.

An overview of the risk assessment and management for the current plan with potential risk mitigation measures and associated residual risk assessment is outlined below in Table 13.

Corangamite Catchment Management Authority 51

Upper Barwon River Seasonal Watering Proposal 2021-22

Table 13. Risk assessment for 2021-22 System Risk Risk Risk description Likelihood Conseq Risk Mitigation actions Lead Remains Risk type ID category Rating organisn. med/ Static/ for action high Dynamic after mitign.

Heavy rainfall following • Undertake detailed monitoring of water levels and CCMA environmental adjust delivery plans based on seasonal conditions deliveries may lead to and forecasts. CCMA unintended inundation • Ongoing communication of delivery plans to CCMA/B CE of private land in the landholders. W Upper BA upper Barwon River, • Limiting maximum delivery rates to reduce risk of CCMA/B Barwo 202 Legal resulting in impacts on Possible Minor Low flooding W Static n 0- landowner activities • Undertake regular communications between CMA River 22 and assets. and Barwon Water to identify local risks (using CCMA operator knowledge) and manage releases accordingly • Reassess acceptable flow limits following willow/constraints removal program Inability to engage with • Continue efforts to seek to establish meaningful CCMA Eastern Maar during partnership arrangements with Eastern Maar planning may lead to a people, leading to ongoing inclusion of T.O. values failure to address T.O. into watering proposals values or damage to • Continue to partner and share knowledge with CE Upper heritage/artifacts and T.O.s to build capacity to actively engage in water BA Barwo Cultural may impact on values related issues 202 Possible Minor Low Static n Heritage or heritage 1- River Note: There may also 23 be some reputational risks if Eastern Maar can't be engaged in environmental water processes

Corangamite Catchment Management Authority 52

Upper Barwon River Seasonal Watering Proposal 2021-22

System Risk Risk Risk description Likelihood Conseq Risk Mitigation actions Lead Remains Risk type ID category Rating organisn. med/ Static/ for action high Dynamic after mitign.

Implementing watering • Review and assess potential risk issues for water CCMA actions for new sites delivery actions and develop specific mitigation supplied from West actions. CE Barwon Reservoir may • Continue to support community and stakeholder Upper BA not be successful due information and engagement processes. Barwo Reputati 202 to lack of information Possible Moderate Medium • Continue to implement upper Barwon restoration Static n onal 0- on flow behaviour and project to restore channel capacity for River 24 constraints with the environmental water delivery result that • Expand flow monitoring capability where possible environmental benefits are not achieved. Community concerns • Engage with key objectors to address information CCMA related to gaps and concerns. establishment and implementation of Barwon Water CE Upper groundwater BA Barwo Reputati remediation plan may Dynami 202 Unlikely Moderate Low n onal be extended c 0- River (incorrectly) to Barwon 25 River environmental release plans, leading to a loss of public/political support for activities The availability of • Continue to engage with the local community to CCMA environmental build understanding of the limitations on the CE Upper entitlements creates a available environmental water entitlements and the CCMA BA Barwo Reputati community expectation processes for identifying and prioritising VEWH Dynami 202 Unlikely Moderate Low n onal (which can’t be met) environmental watering actions. c 0- River that regular “natural” • Engagement in the redevelopment of the SWS to 26 cease to flow events in address environmental water needs. the mid-Barwon and • Consider accessing additional water through trade

Corangamite Catchment Management Authority 53

Upper Barwon River Seasonal Watering Proposal 2021-22

System Risk Risk Risk description Likelihood Conseq Risk Mitigation actions Lead Remains Risk type ID category Rating organisn. med/ Static/ for action high Dynamic after mitign.

low flows/BGA issues in the lower Barwon will no longer occur.

Environmental • Ensure licensing authority is aware of planned CCMA releases do not events and alert it to the need to manage CE Upper achieve compliance by all users. BA Barwo Environ planned/specified flow • Work with SRW to improve diversions compliance 202 Likely Minor Low Static n ment targets due to releases management options and shepherding of 0- River being diverted by other environmental flows through the system. 27 users before reaching delivery site.

Corangamite Catchment Management Authority 54

Upper Barwon River Seasonal Watering Proposal 2021-22

11. Approval and endorsement

I, John Riddiford, the authorised representative of the agency shown below, approve the Seasonal Watering Proposal for the Upper Barwon River system 2021-22.

SIGNED FOR AND ON BEHALF OF Corangamite Catchment Management Authority

______

Signature of authorised representative

John Riddiford

Name of authorised representative

Date

Corangamite Catchment Management Authority 55

Upper Barwon River Seasonal Watering Proposal 2021-22

Appendix 1. Abbreviations

ARI Arthur Rylah Institute CCMA Corangamite Catchment Management Authority DELWP Department of Environment Land Water and Planning EMAC Eastern Maar Aboriginal Corporation EVC Ecological Vegetation Class LAWROC Land and Water Resources Otway Catchment RAP Registered Aboriginal Party SRW Southern Rural Water SWP Seasonal Watering Proposal UBSWAG Upper Barwon Surface Water Advisory Group VEWH Victorian Environmental Water Holder VEFMAP Victorian Environmental Flows Monitoring and Assessment Program WTOAC Wadawurrung Traditional Owners Aboriginal Corporation

Corangamite Catchment Management Authority 56

Upper Barwon River Seasonal Watering Proposal 2021-22

Appendix 2. References

Alluvium. (2021). Upper Barwon, Yarrowee and Leigh rivers FLOWS study update. [Report prepared by Alluvium Consulting Australia for CCMA].

Alluvium. (2020, August). Final Report: Upper Barwon Restoration. [Report prepared by Alluvium Consulting Australia for CCMA].

Bureau of Meteorology (2021) Climate Driver Update Archive. http://www.bom.gov.au/climate/enso/wrap-up/archive/20210316.archive.shtml

Bureau of Meteorology (2021) Rainfall and temperature outlooks. http://www.bom.gov.au/climate/ahead/outlooks/

Department of Environment, Land, Water and Planning. (DELWP) (2006) Central Region sustainable water strategy. https://www.water.vic.gov.au/planning-and-entitlements/sustainable-water-strategies/central-region- sustainable-water-strategy

DELWP (2015). Climate ready Victoria– Barwon South West. [Factsheet]. https://www.climatechange.vic.gov.au/__data/assets/pdf_file/0020/60743/Barwon-South-West.pdf

DELWP (2016) Guidelines for Assessing the Impact of Climate Change on Water Supplies in Victoria. Final. December 2016. V7.0. ISBN 978-1-76047-346-4 (pdf/online)

DELWP (2020) The Central and Gippsland Region sustainable water strategy. https://engage.vic.gov.au/ltwra/central-and-gippsland-region-sws

EMAC (2015) Meerreengeeye ngakeepoorryeeyt – Our Country. EMAC Country Plan accessed from www.emac.com.au

IAP2 International Federation. (2018). IAP2 spectrum of public participation https://www.iap2.org.au/resources/spectrum/

Lloyd et al. (2006) . Environmental flow determination for the Barwon River. [Final report – flow recommendations prepared Lloyd Environmental, Fluvial Systems and Ecological Associates Pty Ltd for Corangamite CMA, Colac].

Wadawurrung Traditional Owners Aboriginal Corporation (2020) Paleert Tjaara Dja – Wadawurrung Country Plan. https://wadawurrung.org.au/resources

Corangamite Catchment Management Authority 57

Upper Barwon River Seasonal Watering Proposal 2021-22

Appendix 3. IAP2 spectrum of public participation

Figure 11. IAP2 spectrum of public participation

Corangamite Catchment Management Authority 58

Upper Barwon River Seasonal Watering Proposal 2021-22

Appendix 4. VEHW Risk matrix

Table 14. VEWH risk rating matrix

Likelihood Consequence

Negligible Minor Moderate Major Extreme

Almost certain Low Medium High Extreme Extreme

Likely Low Medium High Extreme Extreme

Possible Low Medium Medium High Extreme

Unlikely Low Low Medium High Extreme

Rare Low Low Low Medium High

Table 15. VEWH risk likelihood legend

Rating Description Probability

Rare 1 Event may occur only in exceptional circumstances 0-5%

Unlikely 2 The event could occur at some time 5-20%

Possible 3 The event might occur 20-50%

Likely 4 The event will probably occur in most circumstances 50-80%

Almost certain 5 The event is expected to occur in most circumstances 80-100%

Corangamite Catchment Management Authority 59

Upper Barwon River Seasonal Watering Proposal 2021-22

Table 16. VEWH risk consequence matrix Rating Environment Business Costs People Political/ Legal Service Delivery Safety and Well- People and Reputational being Culture

Negligible 1 No material effect Cost impact of up to 2.5% On-site first aid Staff disgruntlement Minimal adverse Non-compliance with Insignificant impact to the Harm on the of allocated operational treatment only local attention (1 legislation, identified partnership's capability in environment, budgets (including capital day only) internally and resulting providing its services - no contained locally budget); in internal inconvenience to within a single OR a cost impact of up to acknowledgement and customers/ stakeholders site/ area. $2.5m process review. Environment affected for days

Minor Harm 2 Limited effect on Cost impact between Minor Complaints, Adverse localised Non-compliance with Minimal short-term the environment, 5%- injuries/illness passively upset, and public attention on a legislation or breach temporary impact to the restricted to a 10% of allocated requiring medical uncooperative single issue over a of duty of care, partnership's capability in single township operational budgets attention short period. (up to 1 identified externally providing its services - or locality. (including capital week) and either (1) customers/ stakeholders Environment budget); resolved without slightly inconvenienced affected for OR a cost impact of up prosecution of or weeks. to $5m civil action, or (2) resulting in prosecution or civil action involving low level of resourcing required to defend, exposure to low level remedies or damages, and low- level risk of negative precedent Moderate 3 Moderate effect on Cost impact >10% of Significant Low morale, Adverse Non-compliance with Significant impact to the Harm the environment, allocated operational injury/illness disengagement, localised legislation or breach partnership's capability in impacting on a budgets (including requiring inpatient increased negative of duty of care providing its services - municipality or capital budget); hospitalisation absenteeism public resulting in customers/ stakeholders multiple localities. OR a cost impact of up and workplace attention on a prosecution of, or inconvenienced Environment to $10m conflict single issue civil action, with one affected for months. over a of high level of sustained resourcing required period (up to 2 to defend; exposure months) to high level remedies or

Corangamite Catchment Management Authority 60

Upper Barwon River Seasonal Watering Proposal 2021-22

damages or high- level risk of negative precedent.

Major Harm 4 Major effect on Cost impact Extensive and/or Major morale Serious adverse Non-compliance with Continuing difficulties in the between permanent issues, high public attention on legislation or breach the partnership's capability environment, $10m$50m injury/ illness absenteeism and more than one of duty of care in servicing impacting on a resignations of key issue over a resulting in customers/stakeholders region staff prolonged period prosecution of or civil over a protracted period or multiple (up to 2 years) action (with all high municipalities. level of resourcing Environment required to defend, affected for 1-3 exposure to high level years. remedies or damages, and high-level risk of negative precedent); or public enquiry Extreme 5 Very serious effect Cost impact of over Death or Partnership wide Very serious public Non-compliance Long term detrimental Harm on the $50m permanent morale issues, outcry over a with legislation or effect on the partnership's environment, disability/ illness mass resignations prolonged period breach of duty of capability in providing impacting on the and absenteeism (greater than 2 care resulting in services to customers/ state or multiple years), or leading prosecution of or stakeholders regions. to a formal inquiry, civil action Environment serious (leading to affected for >3 investigation of imprisonment of years another major an officer and/or political event uninsured compensation payments).

Corangamite Catchment Management Authority 61