Seasonal Watering Proposal for the River System 2020-21

Report prepared for: Victorian Environmental Holder Report prepared by: Wimmera CMA April 2020

Wimmera CMA

For further information on any of the information contained within this document contact:

Greg Fletcher – Wimmera CMA

Wimmera River at Antwerp, February 2020

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Wimmera CMA

Publication details Acknowledgements Wimmera Catchment Seasonal Watering Proposal for The following individuals or Management Authority the Wimmera River System – groups have assisted in the www.wcma.vic.gov.au 2020-2021 preparation of this report. 24 Darlot Street Horsham VIC 3400 Date of publication: 17 April 2020 Erin Round Telephone 03 5382 1544 Tony Baker Facsimile 03 5382 6076 Ben Muir Author: David Brennan Copyright Greg Fletcher Stuart Harradine © Wimmera Catchment Kym Wilson Management Authority 2020 Scott Smith Richard Mintern Disclaimer Publications produced by the However, it is acknowledged that Wimmera Catchment the contents and views expressed Management Authority may be of within this report are those of the assistance to you, but the Wimmera Catchment Wimmera Catchment Management Authority and do not Management Authority and its necessarily reflect the views of employees do not guarantee that the parties acknowledged below. the publication is without flaw of any kind or is wholly appropriate VEWH for your particular purpose and Barengi Gadjin Land Council therefore disclaims all liability for GWMWater any error, loss or other CEWO consequence which may arise from you relying on any information in any Wimmera Catchment Management Authority publication.

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Executive summary

The Wimmera was again faced with challenging conditions in 2019-20 with another year of well below average streamflows. This continues to hamper the scale of possible watering actions and ecological outcomes within the region. Although this should not diminish the importance of the achievements to date with the focus on management being vital for the ongoing survival of water dependent fauna.

These achievements include: • additional water delivered to the Ranch Billabong, near consolidating the environmental and cultural benefits; • avoidance of major flow/ related incidents (i.e. significant kills and algal blooms) despite very dry conditions and record high temperatures in December 2019; • conditions were suitable for the community to enjoy a full suite of recreational benefits on the Wimmera River with anglers enjoying the best fishing outcomes for many years.

This proposal is for the use of available water in the Wimmera Catchment to maximise environmental water related outcomes in 2020-21 to prevent critical losses if conditions remain dry or enhance conditions if wetter conditions prevail. The proposal focuses on the regulated waterways of the lower Wimmera River, Burnt Creek, MacKenzie River, Bungalally Creek and Mt William Creek. The delivery of environmental water to these waterways is intended to support the environmental assets within these waterways such as riparian vegetation, iconic Freshwater Catfish and Platypus , locally vulnerable Southern Pygmy Perch and River Blackfish populations and threatened such as Glenelg Spiny Crayfish and Western Crayfish. These waterways also contain many shared benefits including important cultural heritage sites, provide water for agriculture and public open and sustains a variety of recreational activities such as fishing, swimming, boating and camping.

Conditions continue to be extremely dry, although 2019-20 was marginally better than the record dry conditions in 2018-19. There were some natural flows from the upper Wimmera catchment for the first since 2017 with modest but vital flows continuing along the Wimmera River through from late autumn to mid- spring. This enabled a postponement of environmental water deliveries until late spring to conserve volumes for use in 2020. The dry conditions led to allocations for the Victorian Environmental Water Holder entitlement only reaching 42% in March 2020 and so water carried over from earlier years was again vital for achieving outcomes in 2019-20. Therefore, regulated water availability is steadily reducing and as forecast, complete usage of Commonwealth Environmental Water Holder allocations took place in early 2020. Environmental watering has aimed to provide and minimising deteriorations in water quality. They have to date been successful in achieving these aims with no major negative outcomes such as fish .

This proposal outlines the range of environmental watering actions for the Wimmera River system for the 2020-21 water year. Assuming the dry conditions experienced since 2017 persist, the focus for 2020-21 is again to prevent loss of high value refuge habitat and mitigating water quality declines (especially ) and a key to this will be the effective management of drought refuge pools throughout the system. This in turn reduces the likelihood of fish deaths, algal blooms and die back of fringing vegetation. Should conditions be wetter, than the objective is to continue to pursue vegetation and fish objectives by implementing baseflows and freshes. Fish objectives are achieved by providing baseflows throughout the year as well as spring/summer freshes to stimulate native fish breeding. They will provide opportunities for movement and increase available habitat given water has only been delivered to short sections of these waterways in recent years. Vegetation objectives are provided by implementing baseflows to maintain edge and freshes to maintain existing , promote the establishment of new seed/plants in the growing and maintain and encourage germination of aquatic plants. For the Wimmera River it is very important to provide regular baseflows and freshes to ensure adequate water quality through keeping salinity and dissolved oxygen concentrations at acceptable levels, particularly in the absence of large flows in recent years that would have mobilised and dispersed large quantities of organic material and salt.

Environmental water will be adaptively managed as environmental conditions unfold throughout the year. Four management scenarios have been developed to cover the range of possible conditions. These scenarios and associated watering actions are outlined in Table 21. A wide variety of shared benefits will be provided by environmental watering actions, including watering for cultural outcomes at The Ranch in Dimboola as well as the recreational activities the Wimmera River provides that lead to enormous positive economic and health outcomes for the region. 4 Seasonal Watering Proposal for Wimmera River System | April 2020 | https://login.wcma.vic.gov.au/EDMS/Projects/6715 EWR Planning and Impementation/Final Seasonal Watering Proposal Wimmera River System 2020-21.docx

Table of Contents

Executive summary ...... 4 1. Introduction ...... 7 1.2 Purpose ...... 7 1.3 System Overview ...... 7 1.4 Flow Regime ...... 8 1.5 Priority reaches and measuring points ...... 8 1.7 Water sources ...... 10 2. Engagement ...... 10 3. Shared Benefits ...... 11 3.1 Community Values ...... 11 3.2 Aboriginal Cultural Values ...... 12 4. Flow objectives and recommendations ...... 15 5. Seasonal review ...... 17 5.1 Climatic conditions this year and seasonal outlook...... 17 5.2 Review of 2019-20 watering, ecological observations and monitoring ...... 19 5.2.1 Wimmera River summary ...... 19 5.2.2 Ranch Billabong summary ...... 25 5.2.3 MacKenzie River summary ...... 26 5.2.4 Burnt Creek summary ...... 31 5.2.5 Bungalally Creek summary ...... 35 5.2.6 Mt William Creek summary ...... 35 6. 2020-21 Priority watering actions ...... 39 6.1 Wimmera River Reach 4 Priority Watering Actions ...... 39 6.2 MacKenzie River Reach 3 Priority Watering Actions ...... 39 6.3 MacKenzie River Reach 2 Priority Watering Actions ...... 40 6.4 Upper Burnt Creek Priority Watering Actions ...... 40 6.5 Lower Burnt Creek Priority Watering Actions ...... 41 6.6 Bungalally Creek Priority Watering Actions ...... 41 6.7 Upper Mt William Creek Priority Watering Actions ...... 41 6.8 Lower Mt William Creek Priority Watering Actions ...... 42 6.8 Ranch Billabong Priority Watering Actions ...... 43 6.10 Dock Lake Priority Watering Actions...... 43

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7. Scenario Planning ...... 44 8. Delivery Constraints ...... 46 9. Increasing Knowledge ...... 46 10. Risk Management ...... 47 11. Approval and endorsement ...... 53 12. References ...... 54 Appendix 1: Media Information Regarding Environmental Water Releases ...... 56 Appendix 2: Environmental Flow Recommendations ...... 57 Appendix 3: Flow components that have been delivered from 2005 to 2018...... 66 Appendix 4: Priority Watering Actions ...... 68

Wimmera River at Antwerp, October 2019

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1. Introduction

1.1 Background

Environmental entitlements are available to be released from storages when needed and delivered to waterways to protect or enhance their environmental values and condition. They also lead to a number of broader social, cultural and economic benefits as well. In the Wimmera, environmental entitlements are held by the Victorian Environmental Water Holder (VEWH) and the Commonwealth Environmental Water Holder (CEWH). The Wimmera Catchment Management Authority (Wimmera CMA) is responsible for ensuring environmental water is delivered to streams and in its region through developing and submitting seasonal watering proposals to the VEWH for consideration and managing the delivery of environmental water in accordance with the VEWH’s seasonal watering statements and agreements with the CEWH.

The VEWH prepares a statewide seasonal watering plan each water (financial) year. The plan describes the desired environmental water use for rivers and wetlands across in the coming year, based on seasonal watering proposals submitted by CMAs and Water. The VEWH then prepares seasonal watering statements that authorise CMAs and Melbourne Water to undertake the agreed watering activities. As water availability and seasonal conditions change, the VEWH may prepare additional seasonal watering statements.

In late 2017 Wimmera CMA, VEWH and CEWH developed a partnership agreement under which Wimmera CMA could use CEWH allocations in conjunction with VEWH allocations to meet environmental watering objectives. A new agreement will need to be developed for 2020-21 in the unlikely event that they receive allocations given the current agreement will expire in 2020. 1.2 Purpose

The purpose of the Seasonal Watering Proposal for the Wimmera System is to: • identify the environmental water requirements of the lower Wimmera River, MacKenzie River, Burnt Creek, Mt William Creek, Bungalally Creek and Dock Lake in the coming year under a range of climatic scenarios to protect or improve their environmental values and health;

• inform the development of environmental water priorities in the VEWH’s seasonal watering plan; and

• Inform the development of CEWH plans for its portfolio management in 2020-21.

The proposal is informed by scientific studies and reports that identify the flow regimes required to meet the ecological objectives of the priority waterways. This proposal was prepared in consultation with key stakeholders and partners and has been approved by the Wimmera CMA. It is required under section 192A of the Water Act 1989.

1.3 System Overview

Located in western Victoria, the Wimmera River has a total catchment area of 24,011 km2. Regulated waterways within the Wimmera River catchment include the lower Wimmera River, MacKenzie River, Burnt Creek, Mt William Creek and Bungalally Creek. A proportion of flow in the Wimmera River also flows up the – a creek. Refer to Figure 1 for the location of these waterways. Stretches of the Wimmera River and MacKenzie Rivers have been reserved as National Park, State Park and Natural Features Reserves. Sections of the lower Wimmera River are listed under the Heritage Rivers Act 1992.

These waterways support a diverse and abundant native fish community including Freshwater Catfish, River Blackfish, Southern Pygmy Perch, Australian Smelt, Flat-headed Gudgeon, Common Galaxias, Carp Gudgeon, Obscure Galaxias, Golden Perch and Silver Perch. Occasional captures of Murray Cod and Short- finned Eels have been noted too. The associated floodplain habitats support largely Red Gum-dominated grassy woodland communities, and numerous threatened species of state and national conservation significance. The waterways and associated and floodplain habitats also contain many important cultural heritage sites, provide water for agriculture and public open spaces, and support a variety of recreational activities such as fishing and bushwalking. More detail around the Wimmera River system is available in the Wimmera River System Environmental Water Management Plan (Wimmera CMA, 2015). This document is currently being updated to incorporate subsequent work on wetlands in the system (Dock Lake and the Terminal Lake system) and improvement linkages with other environmental water planning documents. 7 Seasonal Watering Proposal for Wimmera River System | April 2020 | https://login.wcma.vic.gov.au/EDMS/Projects/6715 EWR Planning and Impementation/Final Seasonal Watering Proposal Wimmera River System 2020-21.docx

1.4 Flow Regime

The Wimmera River, MacKenzie River, Burnt Creek, lower Mt William Creek and Bungalally Creek have been regulated for decades, significantly altering their flow regimes. Under natural conditions these waterways would have received much greater flows, particularly during winter/spring. They have been further modified due to processes like channel incision, infilling of deep pools with and dryland salinity which means that releasing environmental water is vital for retaining their values. More detail around the flow regime is available in the Wimmera River System Environmental Water Management Plan (Wimmera CMA, 2015).

1.5 Priority reaches and measuring points

Environmental flow recommendations for waterways in the Wimmera Catchment were initially developed in 2003. They were revised in 2013 to provide more relevant environmental objectives that were endorsed by a community advisory group and considered new knowledge obtained after drought and (Table 1). These recommendations also included adaptable components based on different climatic conditions (drought, dry, average and wet). Flow recommendations for upper Mt William Creek are based on work completed in 2005 (SKM 2005). To facilitate the flow volume determination, process the waterways were divided into reaches with similar channel morphology, flow regimes and ecological values (Figure 1). Refer to the table below for the priority waterway reaches, compliance monitoring points, flow recommendations and report references.

Table 1. Summary of waterway reaches, compliance points and flow study reference. Waterway Compliance Key ecological values identified FLOWS Study reach point Lower Wimmera Alluvium 2013

River Reach 2 Horsham Contains a self-sustaining of Freshwater Catfish. Golden Lower 415200 Perch and Silver Perch are also present (stocked). High quality Wimmera Alluvium 2013 macroinvertebrate population within well-vegetated sections. Supports River Reach 3 abundant native fish, waterbirds, turtle, frog and rakali populations. Lower Lochiel Wimmera Railway Bridge Alluvium 2013 River Reach 4 415246 Contains sections of valuable riparian vegetation which provides No current Lower Burnt important habitat connectivity for terrestrial and aquatic species. Recent compliance Alluvium 2013 Creek fish monitoring indicates that high value fish species are present which point warrants a review of management objectives and flow recommendations. Very high variety and proportion of native fish including River Blackfish, East Southern Pygmy Perch, Obscure Galaxias. Key location for Southern Upper Burnt Wonwondah Pygmy Perch and Obscure Galaxias breeding. Contain a regionally Alluvium 2013 Creek 415223 vulnerable Western Swamp Crayfish population. High quality macroinvertebrate population within well vegetation sections. Very high proportion of native fish including River Blackfish, Southern Upper Mt None Pygmy Perch, Obscure Galaxias. Key location for breeding Southern SKM 2005 William Creek applicable Pygmy Perch, River Blackfish and Obscure Galaxias. Contain a Lake Lonsdale regionally vulnerable Western Swamp Crayfish population ( Lower Mt tail gauge , 2017b). Good quality vegetation within National park Alluvium 2013 William Creek 415203 boundaries with remnant vegetation along the rest of the waterway. No current Bungalally Contains sections of valuable riparian vegetation which provides compliance Alluvium 2013 Creek important habitat connectivity for terrestrial and aquatic species. point Regionally valuable Platypus population which has shown evidence of MacKenzie breeding. Very high proportion of native fish including River Blackfish, No current River Reach 1 Southern Pygmy Perch and Obscure Galaxias. Contain a regionally compliance vulnerable Glenelg Spiny Crayfish population (Ecology Australia, 2017b). Alluvium 2013 points Good quality vegetation within national park boundaries with remnant MacKenzie River Reach 2 vegetation along the rest of the waterway. Excellent quality macroinvertebrate population. Contains sections of valuable riparian vegetation which provides McKenzie MacKenzie important habitat connectivity for terrestrial and aquatic species. Also Creek Reserve Alluvium 2013 River Reach 3 contains good populations of Obscure Galaxias and Southern Pygmy 415251 Perch when it contains water.

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Figure 1. Wimmera system reaches, measurement points and target locations.

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1.7 Water sources

Water available for use in the lower Wimmera River, MacKenzie River, Burnt Creek, Mt William Creek and Bungalally Creek include: • regulated environmental entitlements held by the VEWH and the CEWH • unregulated flows; and • passing flow requirements as detailed in Table 1 in Schedule 1 of the Wimmera and Glenelg Rivers Environmental Entitlement. Forecasts for regulated water availability in comparison to priority watering actions are included in Table 2. In addition to these sources there are periodic transfers between headworks storages which provide environmental benefits.

Table 2. Environmental water volumes required for priority watering actions and forecast allocations for 2020/21 water year under a range of climatic scenarios. WIMMERA REGULATED WATERWAYS EXTREME Inflow Probability of Exceedance VERY DRY DRY AVERAGE WET DROUGHT (likelihood of inflows being more than 90% 75% 50% 20% 95% % indicated) Environmental water required to deliver Tier 1 priority watering actions (ML) for 10,000 10,000 15,000 18,000 29,445 the Wimmera System Forecast carryover (ML) to share between the Wimmera and Glenelg 22,000 Systems Current forecast environmental allocation (ML) for the Wimmera and 30,000 36,000 42,000 52,000 62,560 Glenelg Systems in October 2020 (not including Glenelg compensation flow)

2. Engagement In developing this proposal, consultation with key stakeholders is summarised in Table 3. In addition to consultation listed in Table 3 the Wimmera CMA have had regular discussions with stakeholders and community members including recreational users during the implementation of water releases.

Day-to-day environmental release operations are communicated to the public via a registered SMS service. Quarterly media updates have been published in local newspapers, on the Wimmera CMA website and on social media to update the community regarding environmental releases planned and delivered, fish and vegetation survey results and water quality results. Examples of media updates developed are included in Appendix 1.

Throughout the year the Wimmera CMA have undertaken a number of activities to engage with the community about the environmental watering program, including; • Environmental Water Management Forum (September 2019), Wimmera CMA invited agency and community representatives to attend an information night at the Dimboola Rowing Clubrooms. Presentations were made on the findings from the socio-economic study into Wimmera River by Wayne Street from Street Ryan. An additional presentation was made regarding environmental water delivered and planned, recent monitoring results, current conditions and environmental water availability. Feedback was requested from all groups and agencies with an interest in environmental water in the region around the effectiveness of watering actions; • The Eavesdrop on Nature event in Birchip in April 2019 involved presentations by renowned sound recordist Andrew Skeoch and Goulburn-Broken CMA’s Jo-Anne Deretic around the incredible complexity of sounds in nature and recent advances in acoustic monitoring of wetlands. This was aimed at increasing awareness around frog and bird values at Wimmera Pipeline wetlands; • The Wimmera Machinery Field Days provided an opportunity for Wimmera CMA staff and community members to share information around environmental watering; • A fish monitoring demonstration on the Mt Cole Creek as part of the Project Platypus Landcare Network Christmas breakup given their interest in the feasibility of environmental water to be provided to the creek; and • A short film clip was produced that emphasised the link between water in the Wimmera River and community well-being. It was narrated by well-known marathon swimmer and advocate for river health, Tammy Van Wisse. 10 Seasonal Watering Proposal for Wimmera River System | April 2020 | https://login.wcma.vic.gov.au/EDMS/Projects/6715 EWR Planning and Impementation/Final Seasonal Watering Proposal Wimmera River System 2020-21.docx

It should also be noted that Wimmera CMA participates in a number of groups and committees that provide an opportunity to exchange information around environmental watering actions and outcomes. They include the Yarriambiack Creek Advisory Committee (Yarriambiack Shire), Ranch Billabong Project Committee (Barengi Gadjin Land Council), Diverters’ Committee (GWMWater) and Wimmera River Stakeholders Advisory Group (Hindmarsh Shire).

3. Shared Benefits 3.1 Community Values During dry years, such as 2019-20, water for the environment makes up a large proportion of flows in waterways. Whilst there were natural flows which refilled pools and improved water quality in winter/spring, without subsequent environmental watering conditions to support community values would have diminished through summer and autumn. During dry and drought climatic conditions, environmental flows play a critical role in providing social and recreational benefits for regulated waterways. Events that have directly benefitted from environmental water releases for the Wimmera River this year include; • Water skiing at the Horsham and Dimboola weir pools including for the Kannamaroo Festival (Horsham); • Rowing at Horsham and Dimboola, including the Dimboola Rowing Regatta; • Wimmera River Duck Race to raise money for Wimmera Health Care Group; and • The Horsham, Dimboola and fishing competitions. The status of the Jeparit competition is currently uncertain given the Coronavirus situation.

Other events that indirectly benefit include the New Year’s Event Celebration and weekly Park Run in Horsham, using the Wimmera River as a scenic backdrop. Unfortunately, the Horsham Triathlon did not go ahead in February with concerns cited by the committee around river levels and water quality in the lead up to the event. However, their concerns were ill-founded with the river being very suitable for the event.

Security around water in the Wimmera River continues to mean that the overall community benefits continue to expand. This was exemplified by the Peter Taylor Memorial Barefoot Water Ski Tournament and Night Jump, now in its third year it was moved to late March instead of its usual time in October/November. This was because it was going to serve as a lead-up event to the World Barefoot Titles in New South Wales in April. Organisers predicted that the event would generate $280,000 for Dimboola from the 1,800 attendees. Unfortunately, the event had to be postponed due to the Coronavirus, leading to a substantial blow to the local economy. Horsham Rural City Council have recently purchased paddleboats for regular use in the weir pool and have more broadly made concerted efforts to build linkages between Horsham’s central activities district and the river precinct. At Jeparit, Hindmarsh Shire Council is looking to redevelop the section where the Wimmera River passes the town’s caravan park and recreation reserve.

Street Ryan has continued their work capturing the socio-economic benefits of water in the region’s waterways in 2018-19 enabling a comparison over the three years since the surveys commenced in 2016-17 (it should be noted that the surveys were extended by another month compared to previous ones). Highlights include: • Out of 328,187 participants using the 27 recreational/environmental water sites across the Wimmera Southern Mallee, 84,566 were at the Wimmera River at Horsham and 23,780 were at the Wimmera River at Dimboola. They continue to have the highest and third highest number of participants in the region; • Estimated expenditure for locations on the Wimmera River was $1.55 million, an increase of 13% on 2017-18; • Overnight visitors to the Wimmera River at Horsham, Dimboola and Jeparit contributed an average of $47, $31 and $24 per night respectively. For day visitors these figures were $13, $15 and $8. • Physical and mental health benefits are estimated to total of just over $5 million across the 27 sites, of which the three sites on the Wimmera River at Jeparit, Horsham and Dimboola contributed a large proportion.

The Wimmera CMA will continue to actively support community events including the ones listed previously by consulting with local community groups around environmental water releases and where possible supporting them with environmental water releases where this aligns with environmental objectives and environmental outcomes are not compromised. The benefits for the community along the Wimmera River system since the return of regular flows in 2010 have been enormous through increased recreation opportunities and tourism as well as the sense of wellbeing that comes through seeing water in a waterway 11 Seasonal Watering Proposal for Wimmera River System | April 2020 | https://login.wcma.vic.gov.au/EDMS/Projects/6715 EWR Planning and Impementation/Final Seasonal Watering Proposal Wimmera River System 2020-21.docx

and the life it brings. There is also strong alignment with the Our Catchments, Our Communities program with community values from environmental water being enhanced by improved facilities at Horsham and Dimboola Weir pools (new shelters/rowing pontoons/fish habitat/erosion control/canoe launches). Other waterways (MacKenzie River, Burnt Creek, Mt William Creek) are valued for angling opportunities albeit not to the same degree as the Wimmera River. Dadswell’s Bridge has a walking track featuring the Mt William Creek. Dock Lake is also a renowned bird watching site when it contains water.

Pontoons installed in Dimboola Weir Pool in 2019 to reduce erosion risks 3.2 Aboriginal Cultural Values The Ranch Billabong near Dimboola is a prime example of enhancing aboriginal cultural and environmental values. The site is managed by Barengi Gadjin Land Council on behalf of the and listed as a significant place in their Country Plan, Growing What is Good (BGLC, 2017) which represents the views of a wide cross-section of the Wotjobaluk Traditional Owner community. The billabong is currently connected to the Wimmera River channel by a road culvert constructed by Hindmarsh Shire Council (Walker 2017). The culvert is very high up on the riverbank would only be able to receive flows when the Wimmera River is in . The Country Plan lists as priority goals restoring a natural flooding regime to the billabong system and restoring indigenous and habitats, with particularly attention to controlling priority weeds (BGLC, 2017). There are also plans to improve the site’s amenity and suitability for gatherings and events such as earth oven and bark canoe re-creations (Ben Muir, Wimmera CMA, pers. comm.).

There was the first watering of The Ranch Billabong in December 2018 which was marked by a launch event attended by numerous community members, in particular traditional owners. This was followed by a workshop to map out aspirations for the site going forward. The watering was extremely well received and led to a spark of activity from frogs and birds as well as halving salinity levels. A subsequent watering event took place in late March 2019 as well to further consolidate outcomes through replacing water lost to seepage and evaporation over summer. Additional watering took place in October 2019 which coincided with the Wotjobaluk Cultural Festival and reflected more ‘natural’ timing of inundation.

It should also be emphasised that the whole waterway system in the Wimmera is important to the Wotjobaluk people, being valued in its entirety with heritage values existing through the environment. Furthermore, Native Title is held along much of the lower Wimmera River, the first successful claim in Victoria, reinforcing the significance of these values.

Ranch Billabong – December 2018 (left) and October 2019 (right) showing the improvement in River Red Gum canopy condition 12 Seasonal Watering Proposal for Wimmera River System | April 2020 | https://login.wcma.vic.gov.au/EDMS/Projects/6715 EWR Planning and Impementation/Final Seasonal Watering Proposal Wimmera River System 2020-21.docx

Table 3. Consultation undertaken regarding environmental water management for the Wimmera River System. IAP2 Who Purpose of consultation Form and timing of consultation Issues identified/comments Engagement Wimmera Wimmera CMA Monthly updates of EWR actions in Board reports. Review and NA Informing the Board regarding actions and communication approaches. Nil CMA Board approve draft Seasonal Watering Proposal Involve VEWH in development of proposal to assist with aligning document with Direct engagement and via formal advisory groups (meetings between VEWH Discussion of the likely seasonal forecast for environmental water VEWH requirements Glenelg Hopkins CMA, GWMWater, Wimmera CMA & VEWH, allocation, priority watering actions for a range of environmental Glenelg Hopkins throughout the year such as during Storage Manager Reference Justification for water use in Wimmera River system allocations and risk management issues. Program CMA Group and Western Rivers Advisory Group). Partners Direct engagement and via formal advisory groups. The WCMA are Consult with storage manager to identify operational issues with proposed constantly consulting with GWMWater regarding the seasonal outlook, It is important to receive feedback on water delivery constraints, GWMWater Collaborate releases and likely availability under different scenarios improvements to monitoring and delivery of priority watering actions planned maintenance and upgrades etc. to inform the proposal. through the Storage Manager Reference Group, and directly. Communicate environmental monitoring outcomes, research project outcomes Direct engagement (periodic phone conversations and e-mail DELWP fund a number of projects associated with environmental DELWP and project delivery for a number of projects. updates). water delivery and engagement in the region. Discuss proposed watering actions that can include CEWH water in the unlikely Need to understand local priorities to inform portfolio management CEWH Direct engagement. (periodic phone conversations/e-mail). event that it is available in 2020-21 given dry conditions. and determine outcomes of watering activities. Yarriambiack Shire Discuss likely flow regimes for the Wimmera River and the impact this has on Direct engagement and via formal advisory groups. Attend See Yarriambiack Creek Advisory Committee Council the Yarriambiack Creek Yarriambiack Creek Advisory Committee meetings. Northern Consult Periodic contact throughout the year and via annual environmental The impact of environmental flows on levels in Lake Lonsdale is Councils and Grampians Shire Outline planned flow regimes for the Mt William Creek watering forum e.g. e-mails/phone calls around Mt William Creek an ongoing concern to the council. Agencies Council flows. Hindmarsh Shire Periodic contact throughout the year regarding weir management Councils are very interested in environmental water allocations Work with council to manage weir heights to facilitate events whilst enabling Council such as via onsite meetings, e-mails and via annual environmental available and its impact on the region’s economy, tourism and the flows to pass downstream and mitigating erosion in the weir pool. Also to Involve watering forum. Participation in Wimmera River Stakeholders environment. Also weir management for events (such as Horsham Rural City communicate proposed environmental watering actions and seasonal outlook Advisory Group run by Hindmarsh Shire. paddleboat trial day), maintenance works, erosion issues etc. is Council (HRCC) in relation to likely environmental water allocation for 2020-21 an ongoing requirement. Victorian Fisheries Fisheries Victoria are interested in environmental watering activities to inform Periodic contact throughout the year and via annual environmental Useful to share information on fish population responses Authority fish stocking. watering forum. Consult Parks Victoria are interested in monitoring outcomes and flows relating to land Periodic contact throughout the year and via annual environmental Parks Victoria Nil they manage in the Grampians and the Wimmera Heritage River sections. watering forum. Environmental Yarriambiack Creek Discuss likely flow regimes for the Wimmera River and the impact this has on Direct engagement and via formal advisory groups. Attend The committee are interested in the role of structures (e.g. Groups Advisory Committee the Yarriambiack Creek Yarriambiack Creek Advisory Committee meetings. bridges, culverts) on flows along the creek. Friends of Consult Keen to see more flows along the Bungalally and Burnt Creek. Consult with members of the group in relation to flows for Bungalally Creek and Direct engagement. Periodic discussions with group members and Bungalally and Timing of lower Burnt Creek flows to fill pools is important given Burnt Creek. attend meetings throughout the year when requested. Burnt Creek Group low water availability in Lake Wartook.

The Lake Lonsdale Action Group want to ensure that Direct engagement and via environmental watering forum. Regular environmental water is supplied by a series of storages to share Lake Lonsdale Discuss impact of releases on storage levels with respect to recreation, water discussions with members and attend meetings throughout the year the impacts on water levels. Cease to flow periods coincided with Action Group quality etc. when requested. peak recreation period (December – January) and higher volumes were shared between Lake Lonsdale and Taylors Lake. Contacted Natimuk Field and Game via e-mail with offer to review Field and Game NA draft seasonal watering proposal VRFish Invite to attend annual environmental watering forum. Interested in fish outcomes from ongoing environmental watering Wimmera CMA works with HRCC and the ski club to temporarily Consult raise the water levels to allow water skiing for during the Natimuk Lake Periodic contact throughout the year and via annual environmental Kanamaroo Festival (November 2019) as well as another event in Water Ski Club watering forum. Recreational March 2020. Following the event environmental water was users released to improve the water quality downstream. Ski club has been undertaking revegetation works to reduce Communicate proposed environmental watering actions and seasonal outlook erosion impacts of water skiing. Management of the weir pool in relation to likely environmental water allocation for 2020/21 next watering Dimboola Water Ski Periodic contact throughout the year and via annual environmental level as been important in allowing vegetation to establish. Also year. Club watering forum. the water levels in Dimboola Weir Pool for the planned Peter

Taylor Memorial Comp in late March was a focus given the shift in

timing from the usual timing of the event in Oct/Nov.

Dimboola Fishing Periodic contact throughout the year and via annual environmental Flows have been sufficient to enable the competition to again be a Classic watering forum. success in November 2019. Horsham Triathlon Periodic contact throughout the year and via annual environmental Called off triathlon blaming poor water quality despite no evidence Committee watering forum. to substantiate this. Wimmera Anglers’ Periodic contact throughout the year and via annual environmental Infrequent discussions occur to share information in particular Association watering forum. around instream woody habitat and water levels Dimboola Rowing Periodic contact throughout the year and via annual environmental Infrequent discussions occur to share information around planned Club watering forum. flows for November regatta.

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IAP2 Who Purpose of consultation Form and timing of consultation Issues identified/comments Engagement Angling Club have passed on concerns around water levels Jeparit Anglers’ Periodic contact throughout the year and via annual environmental impacting on their ability to conduct their Easter fishing Club watering forum. competition. Club appears to be in recess given low water levels in Wimmera Hindmarsh Ski Club Invitation to annual environmental watering forum. River and is dry. Horsham Fishing Water level remains stable in the lead up to the event to remove misconception Periodic contact throughout the year, including on-site meetings and Consulted with the committee to ensure the flows and weir pool Competition that environmental flows affect the number of fish caught at the competition via annual environmental watering forum. levels were suitable for the competition. Committee Highlight the value of the Wimmera River for potential canoeing events given Will consider the river as a potential event in the upcoming Canoeing Victoria One off contact via e-mail the positive impact of environmental watering on water levels. calendar of events if there is sponsorship Traditional Owners Consult with the council regarding environmental water delivery and Contact throughout the year as part of the Ranch Billabong Project Barengi Gadjin It is assumed Ranch watering would again be desirable in Collaborate communicate likely deliveries for next season and next watering year. Obtain Committee and via annual environmental watering forum. Fortnightly Land Council 2020/21 information around cultural values where available. meetings about BGLC and CMA shared interests.

Consult with community on environmental water delivery, particularly of those Landholders/ Important to give the community knowledge of what environmental Wimmera from storages with high recreational value, and communicate likely deliveries Media releases and advertisements have been published in local farmers flows are being delivered, environmental benefits recorded and community for next season and next watering year. Raise community awareness regarding newspapers and on our web site. provide an opportunity for discussion and feedback. members, environmental water releases. Inform especially Some landholders appreciate being notified of flows being landholders Inform community (especially landholders) around flows and changes to flow Direct engagement on flow changes via SMS or indirect via CMA released to inform stock movement. Anglers appreciate updates rates. webpage around freshes given they have noted fish are more active when freshes occur.

Consultation with Horsham Fishing Competition around water levels in the lead up to the event has been a focus which resulted in positive feedback.

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4. Flow objectives and recommendations

Environmental Objectives

Long-term environmental objectives that form the basis of this proposal are from the Wimmera River Environmental Flows Study (Alluvium, 2013). These objectives where identified by the Wimmera CMA at the time in consultation with the Wimmera CMA’s Rivers and Streams Advisory Group. The study outlines the flow components that are required to affect the functions and processes that contribute to the over-arching objectives for nominated environmental assets. The Wimmera River Environmental Flows Study supersedes the previous information contained within the Wimmera Bulk Entitlement Conversion – Environmental Flows Study (SKM, 2003) that had previously been the guiding document for environmental watering in the region.

This study included revised and more relevant environmental objectives that was endorsed by community advisory group members. It considered new knowledge obtained after drought and floods and improved understanding of waterway ecology to provide a more rigorous and adaptable set of flow recommendations for different climatic conditions (drought, dry, average and wet).

The environmental objectives and flow components for each asset are summarised in Table 4 and outlined in detail in Appendix 2. They are consistent with the Wimmera River Environmental Flows Study (Alluvium 2013). The exception is the upper Mt William Creek, which was not part of the scope of that study and have been drawn from a previous report, Environmental Recommendations for the Mt William Creek (SKM 2005). The Wimmera River System Environmental Water Management Plan (Wimmera CMA, 2015) outlines in more detail the objectives, recommendations and other matters pertaining to environmental water management (e.g. system operation) in the Wimmera. It is currently being reviewed to include improved objectives to link with broader environmental watering documents required under the Basin Plan.

Studies providing environmental watering recommendations have also been undertaken for the Wimmera River’s terminal lakes system (Jacobs, 2019) and Dock Lake (Jacobs, 2015). These lakes are not normally targeted for regulated environmental water releases but chiefly rely on passing and/or unregulated flows to provide suitable inundation to achieve ecological outcomes although regulated releases are of some value for enhancing terminal lake levels (Jacobs, 2014). Although currently there is no capacity to deliver regulated flows to Yarriambiack Creek, a small percentage of flows in the Wimmera River pass into the Yarriambiack Creek. The flow requirements of Yarriambiack Creek can only be met by unregulated and passing flows.

Hydrological data illustrates that environmental water availability is often less than the water needed to deliver recommended flows. It should also be noted that most of the larger flow components (e.g. bankfull and overbank) cannot be delivered through regulated releases in almost all cases (see Section 8 Constraints). Other factors (e.g. prohibitive channel losses and risks around inundation private land) also make these releases unfeasible. Overbank flow recommendations will only be provided by natural events.

White Browed Babbler – Ranch Billabong – February 2020

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Table 4. Ecological objectives and flow recommendations for Wimmera Catchment rivers/creeks (not terminal lakes). Flow Ecological Flow (ML/day) Waterway Compon Ecological Objectives Value Environmental Objective ent Reach 1 Reach 2 Reach 3 Reach 4 Provide variable flow during low flow season for macroinvertebrates (over woody Wimmera Macroinverteb Achieve SEPP compliant debris to increase as a food source). Flush surface 10-100 ML/d Baseflow NA 15-30 ML/d River rates macroinvertebrate communities from hard substrates for macroinvertebrates. Maintain edge habitats in deep pools and runs, and shallow water habitat availability for macroinvertebrates. Maintain self-sustaining Freshwater Catfish population in the Wimmera River. Maintain endemic fish communities (provide freshes Oct-Dec to assist Maintain endemic and recreational fish spawning/nesting). Restore endemic fish community diversity and abundance by Wimmera Baseflow/ 10-100 ML/d (baseflow) 35 – 400 ML/d ML (fresh) 15-30 ML/d (baseflow) 70 – 200 Native fish communities and self-sustaining providing flow variability to maintain water quality and a diversity of habitats. Provide NA River fresh ML/d (fresh) freshwater catfish population adequate water quality/habitat for fish refuge locations in dry periods. Provide native fish passage. Provide increased flow and variability to support fish movement and diversity of habitat. Maintain submerged and emergent aquatic vegetation quality, diversity and extent Wimmera Baseflow/ Maintain healthy and diverse mosaics for fish habitat. Maintain near permanent inundated stream channel for riparian 10-100 ML/d (baseflow) 35 – 400 ML/d ML (fresh) 15-30 ML/d (baseflow) 70 – 200 Vegetation NA River fresh of water-dependent vegetation vegetation and to prevent excessive in stream terrestrial growth. Prevent ML/d (fresh) terrestrialisation of the lower banks from invasive phragmites. MacKenzie Baseflow/ Sustain a platypus population and facilitate its dispersal into the Wimmera River. 2-27 ML/d baseflow 5-130 ML/d fresh 10 ML/d baseflow 35-190 ML/d Platypus Maintain platypus populations NA River freshes Provide flow variability to maintain diversity of habitat. fresh Protect and restore riparian and floodplain EVCs. Maintain edge habitats in deeper pools and runs, and shallow water habitat availability. Maintain submerged and MacKenzie Baseflow/ Maintain healthy and diverse mosaics emergent aquatic vegetation quality, diversity and extent for fish habitat. Inundate 2-27 ML/d baseflow 5-130 ML/d fresh 10 ML/d baseflow 35-190 ML/d Vegetation NA River freshes of water-dependent vegetation riparian vegetation to maintain condition and facilitate recruitment.. Maintain fresh permanent inundation of stream channel to prevent excessive in stream terrestrial species growth. Maintain edge habitats in deeper pools and shallow water habitat availability for Baseflow/ macroinvertebrates. Provide variable flow (freshes) during low flow season for 2-27 ML/d baseflow 5-130 ML/d fresh, 500-900 ML/d bankfull and 10 ML/d baseflow 35-190 ML/d MacKenzie freshes/ Macroinverteb Achieve SEPP compliant macroinvertebrates (over wood debris to increase biofilm abundance as a food overbank freshes 500-1,000 ML/d bankfull NA River bankfull/ rates macroinvertebrate communities source). Flush surface sediments from hard substrates to support and overbank flows overbank macroinvertebrates. Entrain organic debris in the channel to support macroinvertebrates. Maintain structural integrity of stream MacKenzie Bankfull/ Geomorpholo Maintain the structural integrity of the channel. Maintains floodplain geomorphic 500-1,000 ML/d bankfull and bed and channel and prevent loss of 500-900 ML/d bankfull and overbank flows NA River overbank gy features. overbank flows channel capacity MacKenzie Baseflow/ Increase the baseflow water depth to provide for fish movement. Provide 2-27 ML/d baseflow 5-130 ML/d fresh 10 ML/d baseflow 35-190 ML/d Native fish Maintain endemic fish communities NA River freshes flow variability to maintain water quality and diversity of fish habitats. fresh Baseflow Upper Lower Inundate riparian vegetation to maintain condition and facilitate recruitment. Maintain /freshes/ Maintain healthy and diverse mosaics Burnt Creek Vegetation edge habitats and shallow water habitats and inundated stream channel for riparian 1 ML baseflow, 30-160 ML/d fresh 400 bankfull 1,000ML/d bankfull/ of water-dependent vegetation 45 ML/d bankfull 90 ML/d overbank vegetation and prevents excessive instream terrestrial growth. overbank overbank Entrain organic debris in the channel to support macroinvertebrates. Maintain edge habitats and shallow water habitats and shallow water habitat availability for fish and Macroinverteb Achieve SEPP compliant 1 ML baseflow, 30-160 ML/d fresh 400 bankfull 1,000ML/d Burnt Creek Freshes macroinvertebrates. Also flushes surface sediments from hard substrates for 45 ML/d bankfull 90 ML/d overbank rates macroinvertebrate communities overbank macroinvertebrates. Disturb the /bacteria/organic biofilm present on rock or wood debris to support macroinvertebrate communities. Native fish Maintain edge habitats and shallow water habitats and shallow water habitat Burnt Creek Freshes and water Maintain endemic fish communities 1 ML baseflow, 30-160 ML/d fresh NA availability for fish. Provide variable flow for fish movement and diversity of habitat. quality Maintain structural integrity of stream Bankfull/ Burnt Creek Geomorphic bed and channel and prevent loss of Maintain structural integrity of channel. Maintains floodplain geomorphic features. 400 bankfull 1,000ML/d overbank 45 ML/d bankfull, 90 ML/d overbank overbank channel capacity Baseflow/ Upper Lower Maintain structural integrity of stream Mt William freshes/ Geomorphic bed and channel and prevent loss of Maintain structural integrity of channel. Maintains floodplain geomorphic features. Creek bankfull/ >500 ML/d bankfull/overbank 750/d ML/d bankfull 1,500 ML/d overbank channel capacity overbank Baseflow/ Maintain edge habitats and shallow water habitat availability for near-permanent Mt William freshes/ Maintain healthy and diverse mosaics inundated stream channel for riparian vegetation and prevents excessive instream 5 ML/d baseflow 20-500 ML/d freshes 750 ML/d bankfull 1,500 ML/d Vegetation >500 ML/d bankfull/overbank Creek bankfull/ of water-dependent vegetation terrestrial species growth. Inundate riparian and floodplain vegetation to maintain overbank overbank condition and facilitate recruitment. Provide variable flow during low flow season for fish movement and to maintain Native fish Mt William Baseflow/ water quality and diversity of habitat. Prevent water quality decline by flushing pools 5 ML/d baseflow 20-500 ML/d freshes 750 ML/d bankfull 1,500 ML/d and water Maintain endemic fish communities >24 ML/d baseflow, >1 ML/d - > 52 ML/d fresh Creek freshes during low flows. Wet low and highest benches, entraining organic debris and overbank quality promoting diversity of habitat. Baseflow/ Maintain edge habitats and shallow water habitat availability for macroinvertebrates. Mt William freshes/ Macroinverteb Achieve SEPP compliant Provide variable flow during low flow season for macroinvertebrates (over wood 5 ML/d baseflow 20-500 ML/d freshes 750 ML/d bankfull 1,500 ML/d >24 ML/d baseflow, >1 ML/d - > 52 ML/d fresh Creek bankfull/ rates macroinvertebrate communities debris to increase biofilm abundance as a food source). Flush surface sediments overbank overbank from hard substrates to support macroinvertebrates. Bungalally Bankfull/ Maintain healthy and diverse mosaics Protect and restore riparian and floodplain EVCs. Inundate riparian vegetation to 60 ML/d bankfull 150 ML/d overbank Vegetation Creek overbank of water-dependent vegetation maintain condition and facilitate recruitment. Maintain structural integrity of stream Bungalally Bankfull/ Maintains the floodplain geomorphic features and the structural integrity of the 60 ML/d bankfull 150 ML/d overbank Geomorphic bed and channel and prevent loss of Creek overbank channel channel capacity

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5. Seasonal review 5.1 Climatic conditions this year and seasonal outlook

Whilst better than 2018, conditions in 2019 were very dry and this has continued a sequence of three years over well below average inflows since 2016. Conditions started off in a promising fashion with very good rainfall in May and June, with July and early August being just below average rainfall. In early to mid-August this led to reasonable volumes of runoff from the upper Wimmera River (which did not flow at all in 2018). Unfortunately, rainfall was very limited from mid-August onwards and so inflows steadily dropped away through early to mid-spring. Figure 2 illustrates the cumulative rainfall deficits of three very dry winter/springs and the importance of undertaking more restrained watering actions than might have been the case given the volumes carried over from the wet conditions in 2016.

Figure 2. Bureau of Meteorology rainfall deficiencies from 1 March 2017 to 29 February 2020 http://www.bom.gov.au/jsp/awap/rain/archive.jsp?colour=colour&map=decile&year=2020&month=2&period=3 6month&area=vc).

In contrast to 2018-19, the conditions in in 2019-20 were relatively mild (apart from late December to January) which lessened evaporation losses. Inflows to all storages were very modest (Figure 3), with Lake Lonsdale receiving the proportionally greatest inflows. However this was not ideal from a water resource perspective given its high evaporation losses and poor water quality due to its topographical and catchment characteristics. The more ‘reliable’ and useful storages in the Grampians (Wartook, Moora Moora, Bellfield) had only very small inflows.

Inflows to storages to the end of February 2020 totalled 42,740 ML, tracking along 90% probability of exceedance. This comes on the back of 2017-18 with 70,320 ML and 2018-19 with 46,490 ML in comparison to 2016-17’s 244,600 ML. It rivals drought years like 2006-07 and 2015-16 in terms of inflows, both being just under 30,000 ML of inflows. Therefore, as of March 2020, allocations for high reliability entitlements (VEWH product for Wimmera/Glenelg Rivers) were at 42% whilst CEWH allocations remained at 0% with no prospect of any allocations in the coming months.

Similar to 2017, there was a notable spatial discrepancy in rainfall across the catchment from south-west to north-east except it was reversed with comparatively more rain in the north-east compared to the south-west. Comparisons with 17 Seasonal Watering Proposal for Wimmera River System | April 2020 | https://login.wcma.vic.gov.au/EDMS/Projects/6715 EWR Planning and Impementation/Final Seasonal Watering Proposal Wimmera River System 2020-21.docx

2016 (a wet year with about 30% probability of exceedance) and 2017 and 2018 (very dry years with a 90% probability of exceedance) are shown in Table 5. Although MacKenzie River at Wartook is mostly regulated by Lake Wartook upstream, there have been flows due to upstream pickup and releases to meet target levels at Lake Wartook. Since 2017 most flows have been due to releases for environmental watering and Horsham’s water supply.

Table 5. Annual streamflows from 2016-2019 at gauges in unregulated reaches (Mt William Ck and Wimmera River) and regulated reach (MacKenzie River) Location Flow 2016 (ML) Flow 2017 (ML) Flow 2018 (ML) Flow 2019 (ML) Mt William Creek at 35,022 3,614 264 11,472 Mokepilly Wimmera River at 116,737 3,824 0 11,708 Glenorchy MacKenzie River at 19,572 13,003 8,956 5,752 Wartook

Passing flows in 2019/20 have again been very limited due to the dry conditions however they were very important for providing winter/spring baseflows and freshes for the Wimmera River. Passing flow volumes held in Lake Lonsdale prolonged these flows when they were released in November following the cessation of unregulated flows from the upper Wimmera River. Whilst well below historical averages, it was much better than 2018 when for the first time there was no Wimmera River flows measured at Glenorchy (Table 5) however these limited passing flows led again to a high reliance on regulated releases. Dry conditions were particularly noted in the MacKenzie River/Burnt Creek system with Lake Wartook being at its lowest level since the Millennium Drought which again increased reliance on regulated flows or flows were simply not able to be delivered. Drought contingency planning continues for Lake Wartook in consultation with VEWH and GWMWater, given the ramifications low storage levels has on critical consumptive and environmental water needs.

Table 6. Passing flows for 2016/17-2019/20 for Mt William Creek at Lake Lonsdale and Wimmera River at Huddleston’s Weir Location Passing Flow Passing Flow Passing Flow Passing Flow 2016/17 (ML) 2017/18 (ML) 2018/19 (ML) 2019/20 (ML) Mt William Creek at 3,321 2,078 335 690 Lake Lonsdale Wimmera River at 51,064 1,750 0 262 Huddleston’s Weir

Summer 2019/20, was reasonably mild (apart from late December through to January) and noted for the isolated thunderstorm activity. This led to some minor benefits such as stormwater contributions from Horsham for the Wimmera River, offsetting evaporation at refuge pools and brief increases in MacKenzie River flows. However, virtually all flows in regulated waterways from late spring through to early autumn were due to environmental watering. Therefore significant rainfall in autumn and winter 2020 will be required to fill pools/dams and generate streamflows. With a shortfall in system operating water currently forecast, allocations are likely to be 0% at the start of 2020-21 and this will also affect passing flows (should they take place) through restrictions as prescribed in the Environmental Entitlement.

Low flows on Wimmera River at Wail – October 2019

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Figure 3. GWMWater storage volume comparison to start of March 2020 (GWMWater 2020).

5.2 Review of 2019-20 watering, ecological observations and monitoring

The Wimmera system’s regulated environmental water usage in 2019-20 was planned to be up to 5,900 ML from 1 July to 31 March and up to 4,638 ML from 1 April to 30 June on the volume authorised by VEWH (Seasonal Watering Statements #1, 1a and 1b). In addition to this 1,562 ML was available from the CEWH entitlement. This water was authorised to provide a proportion of baseflows and freshes for several waterways. Some unregulated flows meant that regulated releases were not required for some watering actions and there is a concerted focus on conserving water for watering in 2020-21 given the current resource situation. Results are summarised for various waterways in Table 7. Planning through to the end of June (as of March 2020) indicates that approximately 7,385 ML of regulated water will be used.

Table 7. Summary of the environmental water delivered compared to what was authorised and required to achieve compliance of priority watering actions (PWA).* Does not include Lake Lonsdale releases for Wimmera River Waterway Estimated water required to achieve Tier 1 PWA compliance Planned to be Delivered by under scenario (ML) 31st March (ML) Dry Average Wimmera River 12,740 15,030 5,100 MacKenzie River 3,230 5,060 1,715 Burnt Creek 1,150 1,485 Mt William Creek 900 2,245 670* Bungalally Creek 300 0 Dock Lake 400 0 Total 18,230 24,520 7,385

5.2.1 Wimmera River summary

With very low water environmental water availability coming into 2019-20 and modest unregulated flows over winter and early spring, no releases took place until November. Flows at Lochiel prior to releases commencing were mostly due to unregulated and passing flows from the upper Wimmera catchment with minor additional flows due to 19 Seasonal Watering Proposal for Wimmera River System | April 2020 | https://login.wcma.vic.gov.au/EDMS/Projects/6715 EWR Planning and Impementation/Final Seasonal Watering Proposal Wimmera River System 2020-21.docx

stormwater contributions from Horsham and flows from downstream tributaries (i.e. Norton Creek). However, when the unregulated flows ceased as conditions dried out in October, releases commenced from Lake Lonsdale in November with a combination of withheld passing flows and regulated releases. Releases stopped over the Christmas/New Year’s break to provide a planned cease-to-flow in January. They recommenced early in the new year from Taylor’s Lake to again provide baseflows and summer freshes to Reach 4, with flows arriving in late February due to low release rates and warm conditions over January.

Unfortunately, like two previous years, the hot summer conditions have led to substantial instream losses and the low levels in Lake Wartook have prevented releases for the MacKenzie River from being able to contribute any flows to the Wimmera River. in 2019 the trigger for irrigation diversions from the Wimmera River was met, following the last two years when flows were insufficient to meet the trigger. Although volumes are not expected to be massive (≈40ML) they are cumulative effects when combined with extraction for stock and domestic supply and urban park watering which is probably greater than irrigation use (although unmetered so cannot be confirmed).

Refer to Figure 4. following for flows measured at the Lochiel gauge, downstream of Dimboola from 1st of April 2019 until early March 2020. Releases are planned for the Wimmera River until the end of June (at least) from Taylors Lake and Lake Lonsdale. As shown in Table 8 and Figure 4. environmental water releases have been important in providing habitat and mitigating the impacts of poor water quality.

Flow and Salinity for Wimmera River at Lochiel (415246) with Taylors Lake and Lake Lonsdale releases 200 3000 180 2500 160 140 2000 120 100 1500 µS/cm) 80

1000 Flow (ML/day) Flow

60 ( Salinity 40 500 20 0 0

Flow Lonsdale Releases Taylors Releases Salinity

Figure 4. Flow and salinity at the Wimmera River at the Lochiel gauge (415246) April 2019 - March 2020. Flow peaked at 693 ML/d in August but the Y-axis has been modified to focus on lower flows.

Table 8. Summary of Priority Watering Actions (PWA) delivered for Reach 4 of the Wimmera River 2019/20. PWA delivered for Flow magnitude/ Comment reach 4 Wimmera River duration/ frequency Partially delivered mostly due to a combination of unregulated and regulated Winter/Spring baseflow 30 ML/d flows. Dry conditions meant that it fell short in late spring Summer/Autumn 15 ML/d Limited achievement of this due to low water availability and dry conditions. baseflow Summer/Autumn Not achieved to date, planned for late autumn although only two are likely to 70 ML/d 2-7 days x 3 freshes be delivered. Three delivered (July, August, September). Dry conditions in spring meant Winter/Spring freshes 70 ML/d 5 days x 4 that one more was not able to be achieved. Potential for one in June 2020. One achieved (August) and one almost achieved (July) with flows between Winter/Spring freshes 200 ML/d 3 days x 3 150 ML/d and 170 ML/d 1,300 ML/d 3 days x Unregulated flows insufficient to provide component. (Not regulated water Winter/Spring freshes 2 objective unless unregulated component is large given capacity constraints) 2,000 ML/d 2 days x Unregulated flows insufficient to provide component. (Not regulated water Anytime bankfull 1 objective) Unregulated flows insufficient to provide component. (Not regulated water Winter/Spring overbank 6,000 ML/d 1 day x 1 objective)

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Risks to ecological and physical objectives for the Wimmera River Reaches 3 and 4 are included in Table 9 and Table 10 below. The results highlight for Reach 3 there has been a reduction in risks to all objectives brought about due to the wet conditions in winter/spring 2016, followed by environmental water releases since then, especially in relation to baseflows. This has been important for building resilience to cope with reduced flows compared to previous years should dry conditions continue. Unfortunately the low water availability and high losses due to hit weather and extraction in summer/autumn have led to increases in the risk profiles for Reach 4. This illustrates the contrasting circumstances affecting the two reaches with the section through to Dimboola being in comparatively good condition when contrasted with the section downstream.

Table 9. Risk indices for Fish (blue), Macroinvertebrates (yellow), Vegetation (green), Geomorphology (grey) and Water Quality (pink) for Reach 3 of the Wimmera River.

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Table 10. Risk indices for Fish (blue), Macroinvertebrates (yellow), Vegetation (green), Geomorphology (grey) and Water Quality (pink) for Reach 4 of the Wimmera River.

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A key indicator of the impact of flows on waterway condition in the lower Wimmera River is the salinity levels at (refer to Figure 5). It can be seen how rapidly salinity levels increase when flows reduce or cease. They reached heights not seen since the peak of 45,000 µS/cm in winter 2016 after a prolonged period of 15 months of no flow. The flow that reached the site in April 2020 drastically dropped salinity levels. Whilst no major ecological impacts have been noted as a result of these exceptionally high levels, another year of very low flows would pose more severe risks. Salinity impacts were much less from 2016-2018 and so biota will be coming off higher environmental stress levels going into 2020-21. It should be noted that elsewhere salinity levels were much lower (typically 1000-3000 µS/cm).

Tarranyurk (415247) Salinity and Flow 2019/20 45000 30

40000 25 35000

30000 20

25000 15

µS/cm 20000 ML/day

15000 10

10000 5 5000

0 0

Salinity Flow

Figure 4. Tarranyurk July 2019 to March 2020 flow and salinity measurements.

Wimmera River Angler Report Card Fish Surveys The third round of fish surveys were held in February 2019 by staff from Arthur Rylah Institute (ARI) at eight sites along the Wimmera River from upstream of Horsham (Longerenong) to Jeparit using a combination of fyke nets and electrofishing. Whilst the focus was on angling species of interest (Golden Perch and Freshwater Catfish), there were observations of all the small-bodied fish species that inhabit the lower Wimmera River as well as Carp, Goldfish and Redfin. Four Freshwater Catfish were caught, of which three were juveniles and was a better result than the two collected in 2017 and 2018. It should be noted however Freshwater Catfish are difficult to catch in monitoring work with numbers being typically in single figures in surveys over the years. Pleasingly, the spike in Golden Perch numbers continued with 38 caught in 2019, comparable with the 41 in 2018 and much higher than 11 in 2017. Silver Perch numbers are also steadily increasing with 10 collected this year compared to two and three trapped in 2018 and 2017 respectively. It is planned to undertake another round of surveys in autumn 2020.

Wimmera Carp Monitoring Program Austral Research and Consulting continued the carp monitoring program established in 2016. The program involves repeated surveys at a varying number of sites across the region with varying characteristics (size, habitat, connectivity). The aim is to determine the efficacy of multiple carp removal attempts using boat electrofishing and to determine carp population dynamics to inform the implementation of future actions around environmental watering and potentially the release of the Koi Herpes Virus.

The results again showed that there had not been a large carp breeding event and numbers remain relatively static (Table 11), with very few (five) young of year were caught. This is corroborated by the results of the 2020 Horsham Fishing competition where carp numbers caught have plummeted since 2016 and remain relatively static (Figure 6) with there being a distinct lack of small fish (all carp were over 500g). Golden Perch, Freshwater Catfish, Redfin and Goldfish were also captured. The steady increase in average weights of stocked species is also pleasing and indicative of a healthy functioning foodweb (Figure 6).

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Table 11. Carp numbers caught as part of the Wimmera Carp Monitoring Program 2016-19. Sites labelled c are control sites. Sites in black are riverine sites and in red are weir pool sites (Austral, 2018). Sites are listed in most upstream to most downstream by group. Oct 16 Dec 16 Jan 17 April 17 June 17 June 18 Feb 19 May 19 Lwr Norton c 2 34 7 Quantong 15 15 22 24 9 23 Polkemmet 15 17 47 7 23 Lochiel 2 16 26 42 10 Spears 0 3 17 12 0 19 19 Crossing Antwerp 0 31 21 61 1 23 99 12 d/s Jeparit 45 49 70 31 28 18 23 Weir Bigwater 11 12 26 19 - Horshamc 46 10 17 10 Dimboola 7 4 19 10 17 27 24 19 Jeparit 6 2 13 13 9

Horsham Fishing Competition Results 900 1000

800 900

800 700 700 600 600 500 500 400

400

Number of Fish of Number Ave. Weight (g) Weight Ave. 300 300 200 200

100 100

0 0 2014 2016 2017 2018 2019 2020

Natives Carp Golden Perch Silver Perch

Figure 5. Native fish and carp capture numbers and average weight of stocked native fish species at the Horsham Fishing Competition

5.2.2 Ranch Billabong summary The supply of 5.7 ML in October 2019 led to continuing reductions salinity levels and an increase in waterbird and frog activity. Salinity levels were extremely high prior to the first watering in December 2018 (21,900 µS/cm) which decreased approximately 50% following the watering (9,170 µS/cm) which is still very high. However following the October watering it was down to 3,450 µS/cm in places which was slightly higher than the adjacent river (≈2000 µS/cm). Unfortunately, it was noted that a few very large carp were using the improved conditions to breed. There is a noted increase in birdlife at the wetland, particularly woodland birds and Australian Wood Ducks and Grey Teal continue to use an area that was virtually desolate 12 months previously. A particularly pleasing outcome has been the vast improvement in canopy condition (see below) with River Red Gums in previously poor condition having a prolific burst of leaf growth (Figure 6).

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Figure 6. Ranch Billabong December 2018 (left) and October 2019 (right). 5.2.3 MacKenzie River summary

Conditions for the MacKenzie River similar to those seen in 2018-19 but slightly drier again. As in 2018, the tail end of releases in June was supplemented by very small unregulated flows (Figure 7). Given the precarious state of Lake Wartook with respect to water availability over coming years if conditions remain dry, it was decided to maintain the drought refuge management approach developed in early 2019. After spilling in 2017, two very dry years means that it is still at the lowest levels since the Millennium Drought (Figure 9). It is critical that there is sufficient water available for flows to protect the extremely fragile and important platypus and native fish populations. It is also the main water supply for Horsham, Natimuk and Supply System 6 of the Wimmera Mallee Pipeline.

The refuge pools in the lower MacKenzie River remained at suitable levels through winter and most of spring due to the small unregulated flows and rain on the pools. As conditions became warmer and drier through late spring, releases commenced periodically from Distribution Heads to top up the pools. Unregulated flows from local runoff and transfers to deliver water from Distribution Heads were sufficient to maintain conditions in the mid-MacKenzie River through to summer when releases took place to target refuge pools in the lower MacKenzie River and Burnt Creek.

There are three priority refuge pools in the lower MacKenzie River, the two upstream pools are comparatively close to Distribution Heads and have been targeted for more regular environmental watering (Figure 8) . The most downstream one (at the McKenzie Creek Reserve Gauge) requires a lot more water to reach it however is the largest, deepest and holds water much better due to the base being rock instead of clay/sand so only receives occasional top ups (last in December 2019). From an operational perspective, flows for the lower MacKenzie River from Distribution Heads were again also sourced from Moora Moora Reservoir to reduce the draw on Lake Wartook (Table 12.)

Flow at MacKenzie River at McKenzie Creek Reserve Gauge 2019-20 and Environmental Water Released 40 35 30 25 20

ML/day 15 10 5 0 1/07/2019 1/08/2019 1/09/2019 1/10/2019 1/11/2019 1/12/2019 1/01/2020 1/02/2020 1/03/2020

Flow Distribution Heads Releases Dad and Dave Releases

Figure 7. Flow summary for Reach 3 of MacKenzie River at McKenzie Creek Reserve stream gauge (415451).

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Figure 8. Refuge Pool locations on the lower MacKenzie River and Burnt Creek. 27 Seasonal Watering Proposal for Wimmera River System | April 2020 | https://login.wcma.vic.gov.au/EDMS/Projects/6715 EWR Planning and Impementation/Final Seasonal Watering Proposal Wimmera River System 2020-21.docx

Figure 9. Storage levels for Lake Wartook 2019-20, including forecast levels from October 2019 based on a range of inflow scenarios (Source: Storage Manager, Wimmera-Glenelg System)

Table 12. Summary of Priority Watering Actions (PWA) delivered for Reach 3 of the MacKenzie River. PWA delivered for Flow magnitude/ Reach 3 MacKenzie Comment duration/ frequency River Dry conditions have prevented this with almost no unregulated flows and Baseflows 10 ML/d or natural limited volumes in Lake Wartook/Moora Reservoir. Summer/Autumn Not an objective given the low levels in Lake Wartook and preference is to 35 ML/d 2-7 days x 3 - 4 freshes conserve volumes for flows in future years. Not an objective given the low levels in Lake Wartook and preference is to Winter/Spring freshes 35 ML/d 2-7 days x 5 conserve volumes for flows in future years. Unregulated flows insufficient to provide component. (Not regulated water Winter/Spring freshes 190 ML/d 1-2 days x 1 objective unless unregulated component is large given capacity constraints) Unregulated flows insufficient to provide component. (Not regulated water Winter/Spring freshes 500 ML/d 1 day x 1 objective). Average to wet years only. Unregulated flows insufficient to provide component. (Not regulated water Anytime bankfull 1,000 ML/d 1 day x 1 objective). Wet years only

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Risks to ecological and physical objectives for the MacKenzie River Reach 3 is included in Table 13 below. The high risks that exist for most values are in response to the lack of flows that are due to the current low water availability in Lake Wartook and need to focus on retaining volumes for refuge pool watering should 2020 be dry.

Table 13. Risk indices for Fish (blue), Macroinvertebrates (yellow), Vegetation (green), Geomorphology (grey) and Water Quality (pink) for MacKenzie River Reach 3.

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Josh Griffiths with platypus captured during May 2019 MacKenzie River survey (Photo: M. Pouliot)

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Platypus Surveys and Genetic Analysis Platypus monitoring for the MacKenzie River took place in May and September 2019. A total of four platypuses were caught, including three that have not been caught before. The Catch Per Unit Effort (CPUE) was 0.042 in May and 0.06 in September). This is within the bounds of previous trapping results (e.g. CPUE April 2018 = 0.056). A very positive aspect was that three of the platypuses were caught downstream of Dad and Dave Weir which indicates the increasing repopulation of this reach following the loss of platypuses from there during the Millennium Drought. Indications from eDNA sampling are that the entire reach from Dad and Dave to Distribution Heads is now colonised (cesar, 2019) and bodes well for future recolonization of reaches further downstream should sufficient environmental water be available to provide habitat. There is also a population that has re-established upstream of MacKenzie Falls which was previously lost, coinciding with works to upgrade dam safety at Lake Wartook about twenty years ago.

Preliminary planning is underway to translocate platypuses into the Wimmera River to bolster overall numbers and provide contingencies given that whilst the MacKenzie River population is trending in the right direction, the population is still in a very precarious situation.

Ecology Australia Dry Conditions Planning Surveys Ecology Australia undertook rapid fish surveys at three identified refuge pool sites in January 2019 (Figure 8). Good numbers of native species were found at the two most upstream sites (near the Bos and McInnes Rd sites). However, this was not the case at the McKenzie Creek Reserve Gauge refuge pool (near the downstream McKenzie Creek Reserve Road). Western Swamp Crayfish were found at the most upstream refuge pool on the MacKenzie River, a first for the MacKenzie River (Ecology Australia, 2019). Repeat surveys in June 2020 showed that most of the target species (Western Swamp Crayfish, Southern Pygmy Perch and Obscure Galaxias) were persisting in these pools. It should be noted that wet conditions in June meant that there was much more available habitat (i.e. the pools were full and connected) which would have affected the CPUE. It was also noted that there were young of year Southern Pygmy Perch which was a bonus given the limited flows. The success of this approach in terms of topping up these refuge pools summer/autumn 2018-19 meant that it was applied in summer/autumn 2019-20.

Table 14. Survey results for rapid fish surveys at refuge pools on the MacKenzie River (Ecology Australia, 2019)

5.2.4 Burnt Creek summary

Regulated releases were not required initially due to wet conditions meaning that runoff from the MacKenzie River downstream of Lake Wartook was being transferred via Burnt Creek to Taylors Lake. This continued through the rest of winter and into early spring however (like 2018) volumes were very low (Table 15). One flow briefly in mid-August provided the winter/spring fresh (55 ML/d), this is aligned with the recommended frequency and duration under a drought scenario although another fresh in July was close to this threshold (Figure 10). The relatively dry conditions in spring meant that regulated releases commenced in November from Distribution Heads to maintain habitat through the upper Burnt Creek.

Table 15. Flows during winter/spring for the Burnt Creek at Wonwondah East (415223) Year 2016 2017 2018 2019 Winter/Spring Flow (ML) 20833 4767 2110 2819

No attempts were made to use environmental water to provide recommended flows beyond the provision of drought refuges for high value fish and crayfish species based on the recommendations of Ecology Australia (2019) (Figure 11). It should be noted that some flows were at such low rates that they seeped through the flow measurement control weir and so would not have been recorded. Releases during November were sufficient to just push water through to the end of the Burnt Creek. This helped reduce the decline of fringing and riparian vegetation in the lower Burnt Creek and produced a notable frog response. The infrequent inundation of the lower Burnt Creek has largely precluded the establishment of fish populations, however judging by the extent of frog calls this has in turn seemed to have benefitted frogs with limited of eggs and tadpoles.

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Flow at Burnt Creek at Wonwondah East Gauge 2019-20 and Environmental Water Releases 60

50

40

30 ML/Day 20

10

0 1/07/2019 1/08/2019 1/09/2019 1/10/2019 1/11/2019 1/12/2019 1/01/2020 1/02/2020 1/03/2020

Flow Distribution Heads Dad and Dave Releases

Figure 10. Burnt Creek streamflow at Wonwondah East gauge (415223) and environmental water releases at Distribution Heads and Dad and Dave Weir.

Table 16. Summary of Priority Watering Actions (PWA) delivered for upper Burnt Creek recorded at the Wonwondah East gauge (415223). PWA delivered for upper Flow magnitude/ Comment Burnt Creek duration/ frequency Delivered mostly by unregulated flows from July until regulated releases Baseflow all year 1 ML/d started in November. Cease to flow duration has been greater than recommended due to focus on drought refuge management. Summer/autumn freshes 30 ML/d 3-7 days x 3 Not an objective this year due to low water availability in Lake Wartook 55 ML/d 3-7 days x 1- Unregulated flows achieved the one fresh recommended under a drought Winter/spring freshes 5 scenario. 160 ML/d 1-3 days x Unregulated flows insufficient to provide component. (Not regulated water Winter/spring freshes 1-3 objective). Dry-Wet years only. Unregulated flows insufficient to provide component. (Not regulated water Any time bankfull 400 ML/d 2 days x 1 objective). Ave-Wet years only. Unregulated flows insufficient to provide component. (Not regulated water Overbank 1,000 ML/d 1 day x 1 objective). Wet years only.

Ecology Australia Dry Conditions Planning Surveys As discussed in Section 5.2.2, Ecology Australia undertook rapid fish surveys in January 2019 in the upper Burnt Creek to ascertain the location and value of refuge pools. Two sites were identified between Graham’s Bridge Road and Francisco’s Road that have significant refuge value, especially for Southern Pygmy Perch. The most downstream refuge pool at the Wonwondah East Gauge also contained Southern Pygmy Perch. Western Swamp Crayfish were found at all three refuge pool sites on the Burnt Creek. Live mussels were also found in the middle and lower refuge pool sites on the Burnt Creek – illustrating that these sites don’t completely dry out. Similar to the results for the MacKenzie River, repeat surveys in June indicated that most species persisted. There was also evidence of Southern Pygmy Perch recruitment with young of year individuals caught and gravid female Obscure Galaxias caught at the lower refuge pool in the June survey.

Table 17. Survey results for rapid fish surveys at refuge pools on the Burnt Creek (Ecology Australia, 2019)

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Risks to ecological and physical objectives for the Upper Burnt Creek is included in Table 18 below. The results highlight either a maintenance or slight increase of risks to ecological objectives despite the prevailing dry conditions which is reflected in the limited monitoring results from 2019.

Table 18. Risk indices for Fish (blue), Macroinvertebrates (yellow), Vegetation (green), Geomorphology (grey) and Water Quality (pink) for upper Burnt Creek.

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Gravid female Obscure Galaxias caught from Burnt Creek at Wonwondah East refuge pool, June 2019 (Photo: C. Bloink)

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5.2.5 Bungalally Creek summary

No regulated environmental flows were delivered to Bungalally Creek in 2019-20, which means its last flow was in June 2018 when Burnt Creek flows reaching the Toolondo Channel were routed to the Bungalally Creek The creek typically has a very small, shallow channel which does not retain water well, so preventing the establishment of fish populations. Unfortunately, it is unlikely that there will be sufficient volumes to provide flows prior to June 2020 due to the low volumes in Lake Wartook and need to conserve volumes for higher priority flows should 2020 be dry. There is no stream flow monitoring available on Bungalally Creek.

5.2.6 Mt William Creek summary

Regulated releases were not initially required given unregulated flows coming from the creeks flowing from the north- eastern edge of the Grampians (e.g. Briggs Creek, Mud Hut Creek). The rocky catchment of the northern Grampians means that it is relatively responsive to rainfall events as opposed to the upper Mt William Creek which has a catchment of agricultural land and the eastern edge of the Grampians. The streamflow gauge is located at the very upstream end of this reach, immediately below the reservoir and so flows measured there do not factor in these contributions. However a Portable Automated Logger System (PALS) Unit located downstream at Roses Gap provides water level and salinity data after most tributaries have entered the Mt William Creek (Figure 11). Figure 12 shows the flows at Lake Lonsdale Tailgauge in response to regulated releases and passing flows as well as flows at Mokepilly which is unregulated given it is immediately upstream of Lake Lonsdale (see also Table 19). It highlights that despite reasonably dry conditions in 2019, there were reasonable flows into Lake Lonsdale. This had local benefits but due to the high evaporation rates and comparative pool water quality attributed to Lake Lonsdale they were not widespread.

As in past years, salinity levels were very low when unregulated flows were happening but rose very steeply when passing flows and regulated releases commenced for the Wimmera River via the Mt William Creek as unfortunately water quality in Lake Lonsdale is much poorer than that coming from streams flowing from the Grampians. It incrementally increased both during and following environmental water releases. Unfortunately indications from carp removal works at Roses Gap in March are that local fish populations have been impacted by the dry conditions. Whilst pool habitat has been reasonable the massive annual fluctuations in water quality, with salinity levels changing in levels of magnitude is an ongoing challenge given the need to refill pools and provide flows for the Wimmera River from Lake Lonsdale. Furthermore a small fish event in the Mt William Creek in autumn 2019 (a handful of dead carp) and blue green algal blooms in summer 2020 are indicative of systemic poor water quality in the system. A decision was made following the fish death in autumn 2019 to cease flows given the inherent risks. Releases have taken place from late spring onwards at larger flow rates to reduce risks of blackwater.

Releases took place in March for the upper Mt William Creek given the dry conditions in the upper Mt William Creek with fish monitoring works to determine the effectiveness of watering. This was via the outlet from Fyans Outlet Channel.

Water Level and Salinity for Mt William Creek at Roses Gap 2500 2 1.8 2000 1.6 1.4 1500 1.2 1

1000 0.8 (m) Level

0.6 Salinity (µS/cm) Salinity 500 0.4 0.2 0 0 3/07/2019 3/08/2019 3/09/2019 3/10/2019 3/11/2019 3/12/2019 3/01/2020 3/02/2020 3/03/2020 0:00 0:00 0:00 0:00 0:00 0:00 0:00 0:00 0:00

Salinity Level

Figure 11. Mt William Creek water levels and salinity at Roses Gap

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Flows at Lake Lonsdale Tailgauge (415203) and Mokepilly (415252) and Environmental Water Releases

300

250

200

150 ML/day

100

50

0 1/07/2019 1/08/2019 1/09/2019 1/10/2019 1/11/2019 1/12/2019 1/01/2020 1/02/2020 1/03/2020

Tailgauge flow Mokepilly flow Passing Flows Regulated Releases

Figure 12. Mt William Creek streamflows and regulated releases/passing flows. Flows peaked at about 800 ML/day at Mokepilly in August.

Table 19. Summary of Priority Watering Actions (PWA) delivered for lower Mt William Creek recorded at the Lake Lonsdale Tail gauge (415203) and upper Mt William Creek PWA delivered for lower Flow magnitude/ Comment Mt Wiliam Creek duration/ frequency Delivered by unregulated flows from July until September. Regulated releases started in November, trading off water quality verses pool depth Baseflow all year 5 ML/d or natural considerations. Cease to flow duration < 90 days recommended for drought scenario. 20-30 ML/d 2-7 days Summer/autumn freshes Two achieved (December, February), one more planned (April). x 3 100 ML/d 3-7 days x Winter/spring freshes Achieved the one fresh recommended under a drought scenario. 1-5 500 ML/d 1-3 days x Unregulated flows insufficient to provide component. (Not regulated water Winter/spring freshes 1-3 objective). Dry-Wet years only. 750 ML/d 2-4 days x Unregulated flows insufficient to provide component. (Not regulated water Any time bankfull 1 or natural objective). Ave-Wet years only. Unregulated flows insufficient to provide component. (Not regulated water Overbank 1,500 ML/d 1 day x 1 objective). Wet years only. PWA delivered for upper Flow magnitude/ Comment Mt Wiliam Creek duration/ frequency Boosted habitat availability and water quality. Fish monitoring results to come Refuge pool filling N/A (150 ML total) in later autumn 2020.

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Risks to ecological and physical objectives for the lower Mt William Creek is included in Table 20 below. The results highlight that risks are increasing due to the dry conditions although a focus on providing summer/autumn freshes will lower this risk. The risk posed by shortfalls in winter/spring low flows are not representative of the risk to the entire reach (given the gauge is immediately below Lake Lonsdale) which receives unregulated flows from tributaries like Briggs and Mud Hut Creeks.

Table 20. Risk indices for Fish (blue), Macroinvertebrates (yellow), Vegetation (green), Geomorphology (grey) and Water Quality (pink) for lower Mt William Creek.

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Mt William Creek at Tobacco Rd – November 2019 (left) and February 2020 (right) 38 Seasonal Watering Proposal for Wimmera River System | April 2020 | https://login.wcma.vic.gov.au/EDMS/Projects/6715 EWR Planning and Impementation/Final Seasonal Watering Proposal Wimmera River System 2020-21.docx

6. 2020-21 Priority watering actions

With inflows in 2019-20 again being very low there have been modest allocations, reaching 42% in March 2020 for the Victorian Environmental Water Holder (VEWH) regulated entitlement. No allocation for the Commonwealth Environmental Water Holder (CEWH) product can be foreseen in 2019-20 under any scenario. A conservative approach to watering since 2017 has focussed on setting aside reasonable volumes of carryover for future years should conditions remain dry although there is some uncertainty about if the targeted carryover volume will be achieved going into 2020-21. The targeted carryover volume means that drought refuge protection actions can take place intended to prevent critical losses, but they fall well below the minimum recommended watering requirements under a drought scenario. Actions like water trade or use of the Wimmera Mallee Pipeline to fill refuge pools as per the Wimmera River Drought Refuge Management Strategy (Alluvium, 2018) should be given the utmost consideration given the circumstances and Wimmera CMA has communicated this to VEWH for consideration.

Given at least 42,337 ML is needed to deliver all Priority Watering Actions (PWAs) for the Wimmera River system (not including wetlands) from a combination of regulated, unregulated and passing flows, wet conditions are required to provide unregulated and passing flows as well as boost allocations to avoid shortfalls. Wet conditions also provide high flow rates (e.g. bankfull flows) that cannot be provided by regulated watering actions. Priority Watering Actions are outlined initially in Table 21 and in further detail in Appendix 4. 6.1 Wimmera River Reach 4 Priority Watering Actions

Reach 4 of the Wimmera River is a priority reach based on managing risks to environmental values and the critical role of flow in maintaining water quality for aquatic and riparian . Delivering PWAs to this reach will also facilitate social outcomes such as fishing competitions, rowing regattas and triathlons through improved water quality in town weir pools. In 2020-21 flows will be important in sustaining habitat and water quality to levels that reduce the risks of extreme events like fish deaths and major algal blooms. There is a very high risk that they will take place if these actions do not take place and the risk has increased given the relatively limited flows that took place in 2019-20. It will also help to prevent what was experienced during drought conditions in 2014 and 2015 which meant that the river did not flow beyond Dimboola for 18 months with extremely high and lack of habitat with all but the deepest pools drying out. The ability to provide regulated water will be critical for trying to manage potential blackwater events and/or hypersaline conditions. The limited flows from the upper catchment have meant that large quantities of organic material have built up and could create blackwater conditions should there be a small flow from the upper catchment that can mobilise the organic matter but not provide sufficient subsequent flows to maintain dissolved oxygen levels. Likewise, with increasing salinity levels, there is a need to provide the necessary flows for adequate dilution to avoid mobilising and transporting a slug of hypersaline water downstream.

There are continued positive responses by aquatic vegetation in response to improved water quality and concerted carp removal works. Beds of pondweed (Potamageton spp.) and prolific growth of eelgrass (Vallisneria spp.) have been noted to be supporting large numbers of glass shrimp which in turn have been a ready food source for small- bodied and juvenile large-bodied native fish. Relatively regular flows have also been vital for the maintenance of abundant phytoplankton and populations which is underpinning a productive . Community feedback on condition of the Wimmera River from Horsham through to Dimboola is overwhelmingly positive and attribute this to environmental watering. These gains are at threat should priority watering actions not take place and these pools dry out or contain little water. Flows in this reach will also assist with the planned watering of Ranch Billabong to boost riparian and wetland plant condition, in conjunction with cultural outcomes. 6.2 MacKenzie River Reach 3 Priority Watering Actions

Very high environmental values mean that the MacKenzie River lifts its priority for environmental watering. Important populations of indigenous fish species, platypuses and riparian vegetation rely on flow in the MacKenzie River to persist and disperse. Southern Pygmy Perch and Obscure Galaxias are clinging on in refuge pools targeted for top up flows in 2019-20 and going by recent investigations should have been able to have some limited recruitment (Ecology Australia, 2019). However, River Blackfish remain tucked up at the top of Reach 2 and so having suitable habitat for them to repopulate is important as they can rapidly recolonise areas should conditions be suitable (Zeb Tonkin, ARI, pers. comm.) and there are good numbers in Reach 1.

Surveys in Reach 3 have revealed the presence of Flora and Fauna Guarantee Act-listed Western Swamp Crayfish (Ecology Australia, 2019) therefore making it a priority for ongoing environmental water delivery. This crayfish species does not create its own burrows to live in when waterways dry out and so will die unless it can find a burrow created by other species (i.e. Common Yabby). Should conditions remain dry then the focus will continue to be on maintaining the refuge pools in the upper-mid section of Reach 3 through intermittent baseflows given the low volumes that may 39 Seasonal Watering Proposal for Wimmera River System | April 2020 | https://login.wcma.vic.gov.au/EDMS/Projects/6715 EWR Planning and Impementation/Final Seasonal Watering Proposal Wimmera River System 2020-21.docx

be available from Lake Wartook and Moora Moora Reservoir (Figure 9). Unfortunately, there are unlikely to be sufficient volumes available to maintain shallower pools and the large refuge pool at the McKenzie Creek Reserve Gauge which is the most downstream one. However these pools are located in an outcropping section of sandstone and so retains water comparatively well compared to upstream pools that are underlain by sand and/or clay.

Should conditions improve with wet-average conditions over winter/spring 2020 then priority watering actions will revert to fulfilling environmental flow recommendations with a focus on:

• Longer cease to flows and smaller freshes/baseflows over summer/autumn that may be beneficial in limiting the growth of the Eastern Gambusia population in this reach (Ecology Australia, 2014). Gambusia are a small- bodied, aggressive pest fish species that compete with native fish a frog species for habitat and . Indications are that cease to flows are also important for the growth and recruitment of aquatic vegetation in this reach given the shallow water/ habitat they provide (Chris Jones, ARI, pers.comm.); • A fresh in late autumn will assist in the dispersal of juvenile platypuses into this reach (Melody Serena, Australian Platypus Conservancy. pers. comm.) This is becoming increasingly important as platypuses have appear to have fully repopulated the upstream reach; • A six to seven day fresh has been recommended for this reach in August/September for vegetation outcomes and low flows in autumn will assist in the germination of Water Ribbons (Cycnogeton sp.) (Chris Jones, ARI, pers.comm.); and • Winter flows are also recommended for this reach to facilitate Obscure Galaxias spawning and larval survival (Ecology Australia, 2017a).

Water quality in the MacKenzie River is typically excellent so flows in this reach are important in boosting water quality in the Wimmera River. Prior to spring 2016, due to drought conditions, Reach 3 was completely dry for almost 18 months so native fish and other water-dependent fauna populations have since been recolonising this reach to various degrees depending on the flows delivered. Not providing water to at least protect the refuge pools in Reach 3 will eliminate these gains. The high environmental values of the MacKenzie River provide several flow-on social benefits through the numbers of people who enjoy fishing and birdwatching when environmental water releases are taking place. There was also some community outcry to the lack of flows along the lower MacKenzie River in 2019-20 with an online petition being established. 6.3 MacKenzie River Reach 2 Priority Watering Actions

The MacKenzie River Reach 2 supports the source population of indigenous fish that populate MacKenzie River Reach 3 and Burnt Creek during wet conditions. Platypuses appear to have fully recolonised this reach after disappearing in 2007 when the reach dried out. Expanding the size and spread of the platypus population in the MacKenzie River is vitally important as the upper Wimmera River population is now functionally extinct (Josh Griffiths, cesar, pers. comm.). Also having the River Blackfish population expand along the length of Reach 2 (and ideally into Burnt Creek and Reach 3) is a long-term goal of environmental water management in this reach. Priority Watering Actions for Reach 3 typically remove the need for Priority Watering Actions for Reach 2. However if conditions are exceptionally dry and preclude delivering water to Reach 2 then small volumes will be required to support the environmental values in Reach 2. 6.4 Upper Burnt Creek Priority Watering Actions

As with MacKenzie River Reach 3, priority watering actions may be confined to drought refuge management if conditions remain dry. Refuge pools have been identified at the upper, mid and lower section of this part of Burnt Creek (Figure 8). With only limited volumes potentially available from Lake Wartook and Moora Moora Reservoir if conditions remain dry then the priority will be to maintain these pools through intermittent flows from late spring through to late autumn. Unregulated flows should maintain them during winter and early spring.

Should conditions improve, year-round baseflows will assist the restoration and maintenance of fish communities in the upper reaches of Burnt Creek, especially when in combination with enhanced aquatic vegetation growth and recruitment. Populations of the FFG Act-listed Western Swamp Crayfish have been identified in this reach of Burnt Creek (Biosis, 2013, Ecology Australia, 2017) and surveys in January 2019 have found them at the downstream extent of this reach. Like the MacKenzie River, this section of Burnt Creek is valued by the local community which like to see regular flows and the environmental benefits they provide.

As Burnt Creek is supplied from the MacKenzie River or Moora Moora Reservoir and is therefore highly regulated, without environmental watering the only flows taking place along this reach are typically transfers of inflows into the mid-MacKenzie River to Taylor’s Lake in winter/spring. Therefore, environmental water releases will be critical to supplement these flows, especially in the drier months. During winter/spring baseflows and freshes may be provided by catchment pickup or transfers from Moora Moora Reservoir or Lake Wartook to Taylor’s Lake or releases to lower Burnt Creek, particularly if conditions are average or wet. This will offset the need to make a specific release to target 40 Seasonal Watering Proposal for Wimmera River System | April 2020 | https://login.wcma.vic.gov.au/EDMS/Projects/6715 EWR Planning and Impementation/Final Seasonal Watering Proposal Wimmera River System 2020-21.docx

outcomes in the upper Burnt Creek. A two to three day fresh has been recommended for this reach in August/September for vegetation outcomes (Chris Jones, ARI, pers. comm.) which also aligns with the flow recommendations. Also as with the MacKenzie River, low flows in autumn will assist in the germination of Water Ribbons (Cycnogeton sp.). 6.5 Lower Burnt Creek Priority Watering Actions

Lower Burnt Creek has valuable riparian vegetation in some sections which provides important habitat for terrestrial and aquatic species. Releases in previous years have been noted to lead to enhancement in the presence of frogs and waterbirds, including one of the first discoveries of a Peron’s Tree Frog in the region. Environmental water releases provide a lifeline for maintenance of its values given the complete absence of flow from this reach apart from in periods of flood due to its extremely high levels of regulation. Despite the limited flows, a reasonable diversity of native fish species was captured in this section of the creek in November 2017 which have moved downstream from the Upper Burnt Creek, indicating the potential environmental outcomes that can be achieved. Unfortunately, the absence of flows over summer meant that these fish disappeared. It is anticipated that if water availability substantially improves then these fish outcomes could then be pursued again. There is a contrast in the morphology of the lower compared to upper Burnt Creek in that it still retains a larger number deep pools which can contain water for long periods (>1 month).

Fish monitoring results in the past were not as good which is somewhat attributable to the effect of barriers to fish movement from upstream (Biosis, 2013). However, the use of an undershot weir gate to pass flows through to this reach in conjunction with a pipe outlet (instead of just the pipe outlet) will improve this slightly. A passing flow for the creek has been recommended as part of the review of the storage management rules which may be able to meet some PWAs when it is eventually implemented. There is a strong desire amongst adjacent landholders to see increased flows for this reach and there has been good uptake of riparian enhancement projects to increase its environmental values.

Approximately 150 – 200 ML is required to fill pools in the creek before the PWA of a bankfull flow can take place. Historically the limited capacity of the waterway as well as the low volumes delivered for environmental and stock and domestic purposes has meant that there are two stream crossings that may be impacted by the PWA (Earth Tech, 2006) although works to address have taken place in March 2019 with Horsham City Council receiving funding from Wimmera CMA to increase the culvert sizes which will reduce risks and improve outcomes if the PWA can go ahead. 6.6 Bungalally Creek Priority Watering Actions

Bungalally Creek has riparian vegetation in some sections which provides habitat for terrestrial and aquatic species and due to high levels of regulation, it only receives flows in of flood or environmental water releases (like lower Burnt Creek). The on-going collaboration between the Storage Manager and Wimmera CMA will be important for maximising the opportunities and outcomes from system water that can be directed to the creek if there are very wet conditions, as what happened in 2016 and 2017. A passing flow for the creek has been recommended as part of the review of the storage management rules which may be able to meet some PWAs when it is implemented. Local landholders have a strong interest in the maintenance and enhancement of its riparian ecological values. In April 2019 Horsham Rural City Council upgraded a stream crossing that may be impacted by the PWA (Earth Tech, 2006) with funding provided by Wimmera CMA. Like the lower Burnt Creek, this will reduce risks and maximise outcomes should the PWA take place.

Due to the high level of regulation of this system and the fact that it would only receive flows during high flow events, the creek bed will most probably be completely dry when watering commences. Previous experience shows that about 100 ML is required to enable this reach to be filled and connected before the PWA (bankfull flows) can be delivered.

6.7 Upper Mt William Creek Priority Watering Actions

The upper Mt William Creek supports good populations of endemic fish species and there are no European carp present in this reach due to the downstream barrier of Lake Lonsdale (Biosis, 2012). Following wet conditions in 2010-2011, several dry years caused Lake Lonsdale to dry out in 2015. Good inflows in 2016 led to it reaching its maximum operating level but water levels have been steadily declining since then although moderate inflows in 2019 have prolonged the forecast time for the lake to go dry under a number of inflow scenarios in 2020 (Figure 13). The small section of the creek upstream of Lake Lonsdale at Mokepilly can provide crucial drought refuge for endemic fish species like Southern Pygmy Perch. Protection of fish habitat in this reach with summer-autumn flows is considered important for maintenance of the fish community in this reach (SKM, 2005). The fish community in this reach in turn replenishes Lake Lonsdale during wet years, which like many lakes in the district provides a significant drawcard for anglers. With a dry or almost dry Lake Lonsdale, the action may be required if again winter/spring proves to be dry.

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A regulator has been constructed to deliver water to this location in early 2017, prior to this pumping or temporary structures were required to provide water to these refuge pools and is planned to be used to provide water to the refuge pool in autumn 2018. The PWA has not related to a flow rate but rather topping up refuge pools to ensure that they provide meaningful habitat. This has been a successfully undertaken in the past, triggering Southern Pygmy Perch breeding events (Austral, 2016).

Figure 13. Projected levels in Lake Lonsdale over 2018/19. The trend in 2019/20 is roughly equivalent, with the lake experiencing almost average inflows in 2019, reaching 20,560 ML in September (Source: Storage Manager Wimmera Glenelg System) 6.8 Lower Mt William Creek Priority Watering Actions

Maintenance of intact native fish populations in the lower Mt William Creek in order to facilitate dispersal to the Wimmera River is considered important, as is the need to provide flushing flows to prevent major declines in water quality (salinity) and habitat availability. The creek has a fish population that is almost unique in the Wimmera with a mix of species that are found in more headwater streams (Southern Pygmy Perch, Obscure Galaxias, River Blackfish) with lowland species (Golden Perch, Flathead Gudgeons, Australian Smelt). Monitoring results are highly variable from year to year which are potentially indictive of the importance of the emigration of species from upstream and downstream and challenges with sustaining meaningful fish populations in this reach over a series of years given the vast fluctuations with water quality and water availability.

The ongoing challenge is to balance the provision of habitat with the fact that environmental water supplied is typically much poorer quality than the receiving , especially with Lake Lonsdale at low levels. Unregulated flows from the northern Grampians during winter/spring have typically excellent water quality with salinity levels about 10% that of those in Lake Lonsdale. There are concerns about the impact of poor water quality on fish populations in this reach given impacts like blue green algal blooms and fish deaths in the last 12 months. Also compounding this is the periodic use of flows from Lake Lonsdale to provide demands for the Wimmera River and also during a series of dry years the lake dries out (such as is likely in 2020-21) which prevents flows for this reach. Infrastructure configurations (high rates of leakage) prevent releases from Lake Bellfield from being an adequate backup option. This means the delivery of environmental water for the Upper Mt William Creek becomes even more critical.

This reach also contains very high value macroinvertebrate and vegetation communities given it flows through or near large tracts of public land, particularly the Grampians National Park. The presence of Lake Lonsdale at the top of this reach and historical diversions for consumptive supply means that this reach has been one of the most flow-stressed in all of Victoria (SKM, 2005a). A week-long fresh has been recommended for this reach in August/September to achieve vegetation outcomes (Chris Jones, ARI, pers. comm.) which also aligns with the flow recommendations. Also low flows in autumn will assist in the germination of Water Ribbons (Cycnogeton sp.) This reach also flows through 42 Seasonal Watering Proposal for Wimmera River System | April 2020 | https://login.wcma.vic.gov.au/EDMS/Projects/6715 EWR Planning and Impementation/Final Seasonal Watering Proposal Wimmera River System 2020-21.docx

the locality of Dadswell’s Bridge which has made a concerted effort to improve the community benefits of the creek through construction of a heritage walking trail focussing on the creek.

Typically there have been opportunities to achieve these PWAs through passing flows or regulated releases from Lake Lonsdale to meet objectives in the lower Mt William Creek and Wimmera River, however this has not always been the case, especially under ongoing dry conditions and shifting operational arrangements. Therefore there is a need to specify specific PWAs for this reach given demands for the Wimmera River are more likely to be provided from Taylor’s Lake given the low levels and poor water quality in Lake Lonsdale. 6.9 Ranch Billabong Priority Watering Actions

Three watering events in December 2018, March and October 2019 were successful in terms of raising water levels and significantly dropping salinity. It also led to a rapid responses from frogs and waterbirds. The salinity levels rise in the months after water was supplied and so additional watering events are recommended to further dilute salinity levels and provide suitable habitat for frogs and ducks. The watering will also lead to continued improved health of River Red Gums currently experiencing stress from the dry conditions and saline water remaining in the billabong. It will also lead to improved conditions for culturally significant vegetation species like Old Man Weed (Centipeda cunninghamii). Barengi Gadjin Land Council are also investigating other options such as lowering the height of the culvert with respect to the weir pool water levels. 6.10 Dock Lake Priority Watering Actions

Successful outcomes such as Whiskered Tern and other waterbirds breeding following the water provided to the lake by unregulated flows/spills in spring 2016 indicates the value of Dock Lake becoming a PWA in line with the environmental flow study for the lake (Jacobs, 2015). Given the episodic nature of wetland watering in the Wimmera, and the= low water availability leading into 20120-21 the PWA applies during wet conditions. Environmental water delivery would need to ensure that Green Lake (through which water must be routed to reach Dock Lake) would not increase in volume as a result with water being outfalled at the same water level when inflows commence. This currently requires Green Lake to be nearly full, given the outfall at lower lake levels has silted up as it has not been used for almost 20 years. Green Lake is likely to have high water levels in wet conditions from inflows from its own catchment and Storage Manager operations to protect water quality in Taylor’s Lake.

Mt William Creek at Roses Gap (February 2020)

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7. Scenario Planning Table 21. Summary of the Wimmera System environmental conditions, ecological objectives and environmental water requirements under a range of climatic (inflow) scenarios. Probability of Exceedance (POE) indicates likelihood of inflows being less than the % indicated based on historic inflows (e.g. a 95% Probability of Exceedance year means 95% of years will have greater inflows). Tier 1 are highest priority demands and within Tier 2 (lower priority demands), their relative priorities are in yellow (high), grey (medium) and brown (low). *Extreme Drought scenario allocation forecast estimated based on extrapolation from Very Dry scenario allocation forecast. Wimmera EXTREME DROUGHT VERY DRY DRY AVERAGE WET Catchment 95% POE 90% POE 75% POE 50% POE 25% POE October VEWH Allocation 12,000 ML Allocation against October VEWH Allocation 8,000 ML (20%)* October VEWH Allocation 20,000 ML (50%) October VEWH Allocation 30,000 ML (75%) October VEWH Allocation 40,560 ML (100%) environmental (30%) entitlements (VEWH October CEWH Allocation 0 ML CEWH Allocation 0 ML CEWH Allocation 0 ML CEWH Allocation 0 ML CEWH Allocation 0 ML shared with Glenelg VEWH Carry-over 22,000 ML, CEWH Carry-over 0 ML and not including Spill loss 0 ML Spill loss 0 ML Spill loss 0 ML Spill loss 0 ML Spill loss 0 ML Glenelg compensation flow) Total Available 30,000 ML Total Available 36,000 ML Total Available 42,000 ML Total Available 52,000 ML Total Available 62,560 ML Assumed available to 10,000 ML 10,000 ML 15,000 ML 18,000 ML 28,497 ML the Wimmera Expected climatic Effectively no unregulated or passing flows (< Very little unregulated flow (~ 2000 ML for Some unregulated flows (~ 10,000 ML for Good unregulated flows (~ 50,000 ML for the Significant unregulated flows (>100,000 ML for the conditions and water 1000 ML total flows at Glenorchy) the Wimmera River at Glenorchy) the Wimmera River at Glenorchy) Wimmera River at Glenorchy) Wimmera River at Glenorchy) available Regular unregulated flows for Reach 2 MacKenzie Periodic unregulated flows for Reach 2 Periodic unregulated flows for Reach 2 Regular unregulated flows for Reach 2 MacKenzie River, Expected river Periodic unregulated flows for Reach 2 River, Upper Burnt Creek, lower Mt William Creek. MacKenzie River, Upper Burnt Creek, MacKenzie River, Upper Burnt Creek, lower Upper Burnt Creek, lower Mt William Creek. Frequent conditions (inc. MacKenzie River, Upper Burnt Creek, lower Mt Reasonable passing flows and unregulated releases lower Mt William Creek. Regulated Mt William Creek. Regulated releases passing flows and unregulated releases for the Wimmera unregulated and, William Creek. Regulated releases provide for the Wimmera River and lower Mt William Creek. releases provide flows at other times and provide flows at other times and locations River and lower Mt William Creek. Regulated releases consumptive water) flows at other times and locations Regulated releases provide flows at other times and locations. apart from modest passing flows. provide flows at other times and locations locations. Estimated Passing 0 ML 1000 ML 5000 ML 15,000 ML 50,000 ML Flows

Max. Tier Tier Tier Tier Comment Tier 1b Tier Tier 1 Tier 1b Tier 2 Tier 1 Tier 2 Combined action Comment Tier 1a vol. 1a 1b Comment 1a Comment Comment 1b assuming 1b (ML) 2 (ML) (ML) (ML) (ML) (ML) (ML) (ML) (ML) (ML) (ML) (ML) Reach 3 Baseflows Reach 4 Reach 4 Reach 4 PWAs Reach 4 PWAs meet and freshes PWAs partially PWAs partially partially meet Reach 4 PWAs meet these these (summer/autumn) meet these meet these these Assumes water Reach 3 Baseflows Reach 4 Reach 4 Reach 4 PWAs Assumes water delivered delivered for Reach 4 and freshes PWAs partially PWAs partially partially meet 13170 for Reach 4 PWAs and 12870 PWAs and 5000 ML (winter/spring) meet these meet these these 6000 ML passing flows passing flows 1 flow for 3 flows for Reach 4 Baseflows Assumes refuges with refuges with Assumes Taylors Assumes Taylors Lake Wimmera and freshes 2980 9625 2980 3080 Taylors Lake 6060 2290 750 8350 2320 650 9550 1125 long cease to long cease to Lake source source River (summer/autumn) source flow period flow periods One flow to Two flows to Assumes minor top up pools in Reach 4 Baseflows top up pools passing/unreg Tier 1a assumes 9800 late spring Tier 1 assumes 6000 ML

and freshes 4500 11040 (Aug/Nov) 4500 2160 flows. 3440 7900 ML passing/unreg 2000 9880 7350 6000 and/or supply passing flows (winter/spring) and/or mitigate Blackwater flows via pipeline to blackwater mitigation too. refuge pools

Waterway The Ranch Small volume 20 20 Small volume 20 Small volume 20 Small volume 20 Small volume 20 Billabong

Also assists Also assists Also assists Reach 2 Baseflows Min. 870 ML. Not Burnt Ck PWA Burnt Ck PWA Burnt Ck PWA Min. 1050 ML. Not required and freshes 1200 960 1200 400 1700 required if Reach 3 and refuges in and refuges in and refuges in if Reach 3 PWA provided (summer/autumn) PWA provided Reach 3 Reach 3 Reach 3 Assumes Assumes Reach 2 Baseflows mostly Assumes water Assumes water MacKenzi water Assumes water delivered and freshes covered by 200 2645 200 delivered for delivered for Reach 3 e River delivered for for Reach 3 PWA (winter/spring) unreg/ Reach Reach 3 PWA PWA Reach 3 PWA 3 PWAs Reach 2 Reach 2 Reach 3 Baseflows Min. 5150 ML. Tier 1a PWAs water PWAs water Min. 4625 ML and freshes 4480 Min. 3530 ML 1830 600 2070 2385 800 Assumes unregulated 4120 1030 800 some refuges refuges in Dry recs. (summer/autumn) flows in Reach 3 Reach 3

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Wimmera EXTREME DROUGHT VERY DRY DRY AVERAGE WET Catchment 95% POE 90% POE 75% POE 50% POE 25% POE

Reach 3 Baseflows Refuges 2 freshes and Min. 4360 ML Min. 4885 ML. Tier 1a and freshes persist in 2745 baseflow 1530 Lower than 1530 Min. 4535ML. 1530 3215 Assumes unregulated 2500 2385 (winter/spring) cooler months periods recommended flows Upper Burnt Creek No freshes, Min. 1040 ML Baseflows and Min. 1345 ML Min. 1075 ML Min. 1315 ML. Tier 1a refuge 800 1540 4 cease to 800 150 950 35 395 985 90 675 1180 135 540 freshes 3 cease to flows 3 cease to flows assumes unregulated flows management flows (summer/autumn) Burnt Assumes Assumes Assumes Upper Burnt Creek Creek unregulated unregulated unregulated Assumes unregulated Assumes unregulated Baseflows and flows mostly 100 1080 flows mostly 100 100 flows mostly 200 1255 flows mostly offset 200 2215 flows mostly offset volumes 300 2715 freshes offset volumes offset volumes offset volumes volumes required required (winter/spring) required required required Lower Burnt Creek Fill creek before Fill creek before bankfull 300 300 Bankfull bankfull delivered delivered Upper Mt William Refuge Pool Filling 200 300 200 200 (summer/autumn) Lower Mt William Mt William Assumes Lake Assumes Min. 990 ML 40 Creek Baseflows Min. 955 ML 21 day Creek Lonsdale 1225 Lonsdale dry, 960 day cease to 700 255 135 955 375 Min. 1135 ML 1135 300 and freshes cease to flow dry/unusable unusable flow (summer/autumn)

Lower Mt William Baseflows and Unreg/passing Unreg/passing Shoulder period Tier 1 assumes 2000 Tier 1a assumes 2000 ML 1200 200 200 1090 1290 2000 2240 2000 freshes flows only flows only (Nov/June) ML passing flows passing flows (winter/spring) Volume includes filling Volume includes filling Bungalally Bankfull creek before bankfull 300 creek before bankfull 300 Creek delivered delivered Low level Not to increase water in Dock Lake 400 inundation Green Lake Total 10,000 56710 10,000 8,580 15,000 13,310 3,135 18,000 22,105 15,670 29,445 14,265 15,635 Demand Environmental objectives Flow Objectives Increase platypus populations (abundance and distribution) Provide continuous baseflows to the lower MacKenzie River to sustain a permanent connection with the Wimmera River to increase available Platypus habitat for the MacKenzie River platypus population and allow natural dispersal to other areas. Provide adequate freshes to allow connectivity between habitats from April to June to facilitate annual dispersion of Platypus juveniles. Maintain self-sustaining freshwater catfish population in the Wimmera River. Maintain self-sustaining endemic Provide sufficient baseflows and freshes to maintain habitat and water quality at suitable levels as well as larger freshes to enable movement Native fish fish communities in Wimmera River, MacKenzie River, Mt William Creek and upper Burnt Creek. Maintain native between pools to more suitable habitat for breeding or persistence during periods of no/low flows. recreational fish species in the Wimmera River. Maintain suitable conditions (water quality and habitat) for a diverse and abundant macroinvertebrate community. Provide sufficient baseflows and freshes to maintain habitat and water quality at suitable levels as well as larger freshes, bankfull and overbank Macroinvertebrates flows to disturb and flush surface sediments from hard substrates to increase available habitat and food resources (e.g. through washing organic matter into the river channel from floodplain, benches) Maintain submerged and emergent aquatic vegetation quality, diversity and extent. Low flows to prevent growth of terrestrial vegetation in base of channel and enables growth and recruitment of aquatic species (ribbon weed, weed and eel grass). Freshes in winter/spring to lead to flow-dependent vegetation growth and recruitment through temporarily inundating Water-dependent sedges/rushes and providing suitable conditions for mudflat species (knotweeds/sneezeweeds). Bankfull and overbank flows are important for Vegetation maintaining the condition of floodplain vegetation through triggering recruitment as well as replenishing freshwater sources for River Red Gum and Black Box communities. Provide flows to try to prevent the exponential increase of salinity levels which cause fish kills, dieback of fringing Provision of low flows and small freshes in the Wimmera River are vital for reducing water quality impacts through diluting and dispersing saline Water quality and emergent vegetation and macroinvertebrate communities. Also mitigate issues with high nutrients levels intrusions. In all waterways low flows provide a level of mixing and oxygenation to reduce risks of potential blackwater events and leading to blue green algal blooms and organic matter creating blackwater events. blue green algae blooms. Geomorphic Maintain channel capacity and diversity as well as prevent colonisation of waterways by terrestrial plant species. Low flows prevent terrestrial species or species that cannot tolerate permanent inundation from growing in waterway channels. Higher freshes, processes bankfull and overbank flows create scouring to maintain diversity of channel shape (e.g. pools, benches). High priority carryover requirements Refuge Protection Volumes (7000 ML Wimmera River, 1000 ML MacKenzie River, 1000 ML Mt William Creek, 500 ML Burnt Creek) Appendix 3 contains more detail regarding PWAs in relation to ecological objectives.

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8. Delivery Constraints The Wimmera River System Environmental Water Management Plan (Wimmera CMA, 2016) outlines delivery constraints in detail. Given the Wimmera-Mallee Headworks system was designed to harvest water to be released into the former stock and domestic and irrigation channel systems at comparatively modest rates, releases are only typically able to provide baseflows and freshes. Where bankfull and overbank flows are able to be provided (lower Mt William Creek, MacKenzie River and Burnt Creek) instream losses in swampy areas and risks to inundating freehold land make these releases unfeasible. Another factor is the inability to implement adequate rates of rise and fall for freshes in some locations due to the manual operation of some regulators. This is gradually being addressed through a series of repairs and upgrades in the last 12-24 months including with VEWH funding repairs and upgrades to locations like Dad and Dave Weir and Wimmera CMA funding GWMWater to automate valve outlets at Lake Lonsdale.

The key delivery constraint in 2020-21 is likely to be the continuation of low levels in Lake Wartook and Lake Lonsdale which means that unless there are significant inflows into these storages, many priority watering actions for the MacKenzie River, Burnt Creek, Bungalally Creek and Mt William Creek will be unachievable.

9. Increasing Knowledge Monitoring of waterways is critical in order to better understand the effectiveness of environmental watering activities across a range of climatic conditions. This enhances community confidence in future environmental watering activities and enables adaptive management of future environmental flows.

Although this Seasonal Watering Proposal has been developed using the best available information there are still key knowledge gaps and recommendations that remain that can enhance environmental water management in the Wimmera for the benefit of the entire region.

Environmental water deliveries are underpinned by an adaptive management approach. Compliance points for priority reaches are often some distance downstream, a higher release rate is required to cover instream losses through seepage, evaporation and diversion experienced between the delivery point and the compliance point. Therefore ongoing monitoring of flow rates at stream gauges enables environmental flows to be increased or decreased to efficiently meet recommendations. In time the current dataset will be increasingly refined to enable effective and efficient environmental water delivery through better understanding in-stream losses and timing of flows along various waterways.

Compliance monitoring is needed to show flows have been delivered in accordance with recommendations and at the times specified to target areas as precisely and as efficiently as possible. Locations where stream monitoring is needed include: Bungalally Creek, lower Mt William Creek at Dadswell’s Bridge or Roses Gap, Reach 2 of the MacKenzie River near Distribution Heads Weir and lower Burnt Creek at the Western Highway crossing. If funded, the installation of these gauges will significantly improve environmental water managers’ decision making through ensuring regulated releases are providing the recommended volumes at compliance points as well as quantifying the effect of various flow components on water quality. The installation of Portable Automated Logger System (PALS) unit at Roses Gap, funded by VEWH has been a valuable tool to inform decision making around environmental water releases.

Given the substantial expenditure of public funds that has been undertaken to recover water for environmental flows there is a need to demonstrate the outcomes this will achieve. Recommended condition monitoring, required to document trends and provide context for intervention monitoring though answering key questions around flow-ecology relationships are listed below;

• Fish monitoring provides a valuable annual snapshot into the ecological response of environmental flows. Annually sites on the Wimmera River will be monitored as part of the Angler Report Card program instigated by DELWP although the focus is on angling species rather than small bodied species. Occasionally other fish monitoring programs (e.g. Murray Darling Sustainable Rivers Audit, regional fish monitoring snapshots) will complement this data;

• VEFMAP has been focusing on vegetation and fish responses to environmental watering on the MacKenzie River, Burnt Creek and Mt William Creek in in 2017-18, with vegetation continuing into 2018-19 and moisture measurements taking place through this period into 2019-20. Following the write up of these results in 2019-20, it will inform future monitoring efforts on these waterways (subject to funding);

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• Should good water levels be present in regulated wetlands (Lake Hindmarsh, Dock Lake) bird monitoring will take place; and

• Continue annual platypus surveys using trapping and e-DNA sampling in the MacKenzie River with the option to include Burnt Creek if deemed worthwhile.

10. Risk Management

Risk assessment and management is an important aspect of environmental water planning. A teleconference was undertaken with VEWH, CMAs and GWMWater on 24 February 2020 to discuss risk management and environmental watering in detail. Table 22 illustrates the various risks covered in this workshop (likelihood and consequence) associated with planned environmental flow components.

Horsham Weir Pool – October 2019

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Table 22. Risks associated with environmental water release components planned for 2019-20.

Legend for Table 1. Risk category abbreviations are: Env. – environment/sustainability; BC – business cost; Safety – People/safety/wellbeing; Rep – Political/reputation; Legal – legal consequence; Service – service delivery 2. L refers to the Likelihood of a risk occurring. Abbreviations for consequence ratings are: AC – almost certain; L – likely; P – possible; U – unlikely; R - rare 3. C refers to the Consequence if the risk occurs. Abbreviations for consequence ratings are: N – negligible; Min – minor; Mod – moderate; Maj – major; Ext - extreme

No. Risk Risk description L2 C3 Risk Mitigation actions Lead category rating organisn. for 1 action

1 Env Insufficient water available for proposed L Maj Extreme Adaptively prioritise and revise watering actions to CMA/WRAG watering actions to meet environmental optimise outcomes from water available considering objectives. seasonal conditions, including consideration the need to reserve contingency volumes for the following season. Identify any reservoir release constraints due to low CMA/WRAG water levels and adapt plans accordingly Maximise use of consumptive water en-route for GWMWater environmental benefit. Communicate with community and stakeholders CMA around planned watering actions and any revisions required. Undertake extra monitoring to guide complementary CMA actions (e.g. carp removal, fencing). Undertake studies to identify key refuge areas for protection in the Glenelg and Wimmera systems. CMA Where feasible, deliver water via pipelines to key drought pools on the Wimmera River CMA

2 Env Environmental water deliveries may generate or L Mod High Ongoing monitoring to inform water deliveries. CMA mobilise poor quality water (e.g. blackwater, Adapt flow management based on antecedent BGA, salinity), with adverse water quality and conditions and local knowledge. CMA environmental outcomes; or Maximise use of consumptive water en route for environmental benefit.

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No. Risk Risk description L2 C3 Risk Mitigation actions Lead category rating organisn. for 1 action

Areas not targeted for environmental watering Establish environmental reserve to manage GWMWater actions experience poor quality water (e.g. management needs. blackwater, BGA), with adverse water quality Communicate around current conditions and revised VEWH and environmental outcomes objectives. Undertake complementary actions, including provision CMA of information to the community CMA

3 Env Environmental deliveries create improved P Min Medium Adaptively manage flow to incorporate new knowledge CMA conditions for non-native species (e.g. carp, from monitoring and research. invasive weeds, rabbits, foxes) leading to Monitor invasive species extent and control existing CMA adverse environmental impacts. populations (e.g. opportunistic removal of carp in dry conditions). (Note: This risk addresses the incremental Install physical barrier to prevent translocation (e.g. CMA impact of environmental water deliveries on pest carp barriers). plant and animal populations, noting that even in Develop management agreements with landholders CMA the absence of environmental delivery actions that include pest plant and animal control measures. these pests are likely to spread in waterways Communicate data from fish surveys etc. to inform the with adverse environmental impacts). community on pest species and outcomes of control CMA measures.

4 Rep Inability to demonstrate that environmental water L Mod High Seek additional funding for and undertake targeted CMA objectives have been achieved, which may lead local monitoring (leveraging existing data sets where to a loss of public/political support for activities. possible). Invest in monitoring and research to address VEWH/ knowledge gaps and influence existing monitoring DELWP programs. Share new knowledge to promote adaptive VEWH management. Communicate monitoring results to local communities. CMA

5 Legal Environmental releases cause unauthorised P Mod Medium Ensure the currency of any landholder agreements for CMA inundation of private land, resulting in impacts environmental watering actions. on landowner activities and assets.

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No. Risk Risk description L2 C3 Risk Mitigation actions Lead category rating organisn. for 1 action

Ongoing communication with GWMWater and land CMA managers in planning and delivery phases. Consider weather forecasts when conducting GWMWater environmental releases and reschedule deliveries if forecasts indicate potential for flooding. Test and monitor delivery rate and respond to potential GWMWater incidents. Maintain and inspect infrastructure, including upgrading GWMWater infrastructure where required before delivery occurs. Identify likely areas of impact by understanding historical impacts and previous experience, and modify CMA flow planning, or undertake works to reduce risk of inundation.

6 BC Insufficient staff resources available to deliver all L Mod High Continue to actively prioritise actions to match available CMA planned environmental watering actions, leading resources and ensure priority actions are delivered. to cancellation or interruption of deliveries. Ongoing communication with GWMWater to CMA understand constraints and develop a schedule of delivery to manage staff resources. Implement remote monitoring to minimise staff time in GWMWater the field, within available funding. Provide delivery plans with required lead time prior to CMA target delivery date (usually 2 weeks). Ensure timely approval of seasonal watering VEWH statements. Upgrade infrastructure to reduce the need for manual CMA operations. Adjust delivery timing to avoid holidays, weekends and high-risk periods for resourcing. CMA

7 BC Volume delivered or released exceeds volume R Mod Medium Communicate seasonal watering statements to all VEWH approved and/or ordered for use in the event or partners. year. Monitor delivery rate, provide delivery data to GWMWater CMA/VEWH and respond to potential incidents.

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No. Risk Risk description L2 C3 Risk Mitigation actions Lead category rating organisn. for 1 action

Monitor water use against volume approved for use in CMA seasonal watering statement and adapt water orders if required. Monitor water use against volume approved and VEWH undertake regular communications with CMA and GWMWater as part of portfolio management activities. CMAs to review and clarify ordering processes with GWMWater and update Operating Arrangements VEWH document as required.

8 Safety Where delivery structures are unsafe and have R Ext High Upgrade or modify infrastructure to improve safety. Asset owner limitations on their operation, planned Modify method of operation to avoid unsafe work environmental deliveries may not be feasible practices and update safety procedures to reflect this Asset owner leading to a failure to achieve environmental (Note: safe work procedures will need to be outcomes. communicated to community/volunteer resources as well as agency staff where they undertake structure operations). 9 Env Flow rate at environmental flow compliance L Mod High Install/upgrade stream gauge monitoring to improve CMA point not able to be demonstrated, which may ability to demonstrate target flow rate achievement. lead to failure to achieve target flows and Consider data collection and modelling studies to CMA environmental benefits not being achieved. improve understanding of flow behaviour of systems. 10 Env Target flow rate at environmental flow L Mod High Monitor flow rate and adjust delivery volume within CMA compliance point not achieved due to approved volume. environmental conditions, (for example high Use flow forecasting tools/modelling to better GHCMA losses at very dry sites, hot weather causing understand and allow for losses excessive evaporation, antecedent conditions Arrange releases from weir pools to complement WCMA and inflow rates) and environmental benefits not environmental deliveries. being achieved. Consider adjusting delivery timing to avoid holidays, CMA weekends and high-risk periods for system operations resourcing. 11 Env Target flow rate at environmental flow release or U Mod Med Monitor flow rate and adjust delivery to meet ordered GWMWater measurement point not delivered as ordered, flow rates. leading to sub-optimal environmental outcomes. Ongoing communication with the CMA to manage GWMWater infrastructure or maintenance constraints. 51 Seasonal Watering Proposal for Wimmera River System | April 2020 | https://login.wcma.vic.gov.au/EDMS/Projects/6715 EWR Planning and Impementation/Final Seasonal Watering Proposal Wimmera River System 2020-21.docx

No. Risk Risk description L2 C3 Risk Mitigation actions Lead category rating organisn. for 1 action 12 Safety Environmental releases create rapid or R Ext High Communicate flow deliveries to communities and key GWMWater/ unexpected changes in flow conditions, resulting stakeholders and avoid large flows or rapid changes in CMA in injury to river user1 flow rate during periods of high river use. (e.g. using community SMS stock management updates services). Erect signage where appropriate. GWMWater/ CMA Consider safety management around relevant GWMWater automated structures. 13 Rep Changing seasonal conditions results in L Mod High Ensure community is informed about intended watering CMAs changes to previously announced watering objectives and the scenario planning process used. plans, which leads to a loss of community Provide regular local, place-based updates on planned confidence in environmental water delivery actions and the current/changing situation in CMAs management. river systems leading to changed actions.

Undertake broader awareness programs focussing on (Note: These proposed mitigations are also the importance of e-watering, its complexity and the VEWH relevant to Risk 14) need for adaptive management. 14 Rep Community groups not supportive of L Maj High Engage with the local community through a variety of CMA environmental watering delivery. avenues (e.g. workshops, forums, individually to communicate benefits of environmental watering. Develop state-wide communication products and VEWH engage with peak bodies Each organisation to share their intended CMA/VEWH environmental water related communications plans with all partners. Provide the community with information on the risks CMA and management changes implemented in response to drier conditions.

1 There is a need to align state-wide practice in relation to warning processes for environmental releases. The VEWH has initiated a project to address this issue. 52 Seasonal Watering Proposal for Wimmera River System | April 2020 | https://login.wcma.vic.gov.au/EDMS/Projects/6715 EWR Planning and Impementation/Final Seasonal Watering Proposal Wimmera River System 2020-21.docx

11. Approval and endorsement

I, the authorised representative of the agency shown below, approve the Seasonal Watering Proposal for the Wimmera system 2020-21.

SIGNED FOR AND ON BEHALF OF Wimmera Catchment Management Authority

Signature of authorised representative

Name of authorised representative: David Brennan, Chief Executive Officer

Date: 17 April 2020

Wimmera River at Polkemmet (December 2019)

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12. References

Alluvium (2013) Wimmera Environmental Flows Study. A report to the Wimmera Catchment Management Authority, Alluvium, Melbourne

Alluvium (2018) Wimmera River Drought Refuge Management Strategy, A report to the Wimmera Catchment Management Authority, Alluvium, Melbourne

Austral (2016), Environmental Watering of Mt William Creek at Mokepilly. A report for Wimmera CMA Austral Research and Consulting, Kirkstall

Austral (2018), Wimmera Carp Monitoring Program. A report for Wimmera CMA Austral Research and Consulting, Kirkstall

BGLC, (2017) Growing What is Good, Country Plan, Voices of Wotjobaluk Nations, Wotjobaluk, Jaadwa, Jadwadjali, and Jupagulk Peoples, Barengi Gadjin Land Council, Horsham.

Biosis (2012) Fish community assessment of the upper Mount William Creek catchment, A report to the Wimmera Catchment management Authority, Biosis Research Pty. Ltd., Melbourne

Biosis (2013) Fish community assessment of the Burnt Creek and Lower MacKenzie River catchment, A report to the Wimmera Catchment management Authority, Biosis Research Pty. Ltd., Melbourne cesar (2018) Platypus distribution and relative abundance and genetic health in the MacKenzie River 2018, report prepared for Wimmera CMA, cesar consulting, Parkville, VIC.

Earth Tech (2006) Influences on Environmental Water Releases Phase 1 Stage 1. A report to the Wimmera Catchment Management Authority. Earth Tech, Canberra.

Ecology Australia. (2014). Fish Monitoring of Burnt Creek and the Lower MacKenzie River, report prepared for Wimmera CMA by C Bloink, Fairfield.

Ecology Australia. (2017a). 2017 Fish Monitoring of Burnt Creek and the Lower MacKenzie River, report prepared for Wimmera CMA by C Bloink and K. Stevenson, Fairfield.

Ecology Australia. (2017b). Targeted crayfish surveys of upper Wimmera River catchments, report prepared for Wimmera CMA by C Bloink and K. Stevenson, Fairfield.

EnviroDNA (2017a), Assessing distribution of blackfish in Mt William Creek, report prepared for Wimmera CMA, EnviroDNA, Parkville.

EnviroDNA (2017b) Investigating the current distribution of platypuses, rakali and blackfish in the upper Wimmera region, report prepared for Project Platypus, EnviroDNA, Parkville.

Government of Victoria (1989) Water Act, Act No. 80/1989, Government of Victoria, Melbourne

Government of Victoria (1992) Heritage Rivers Act, Act No. 36/1992, Government of Victoria, Melbourne

Government of Victoria (2010) Wimmera and Glenelg Rivers Environmental Entitlement, Government of Victoria, Melbourne.

Jacobs (2014) Optimising Environmental Entitlement Use for the Wimmera River and Terminal Lakes, a report for Wimmera CMA, Jacobs Group (Australia), Melbourne.

Jacobs (2015) Dock Lake FLOWS Study, a report for Wimmera CMA, Jacobs Group (Australia), Melbourne.

Jacobs (2019) Review of the Wimmera Terminal Lakes Environmental Water Requirements, a report for Wimmera CMA, Jacobs Group (Australia), Melbourne.

SKM (2005) Environmental Flow Recommendations for Mt William Creek. A report to the Wimmera Catchment Management Authority. Sinclair Knight Merz, Melbourne.

SKM (2005a) FSR Project – Summary of Hydrologic Stress Index Results, Sinclair Knight Merz, Melbourne

Street Ryan (2019) Wimmera Southern Mallee: Socio-Economic Value of Recreational and Environmental Water, Street Ryan, Gisborne. 54 Seasonal Watering Proposal for Wimmera River System | April 2020 | https://login.wcma.vic.gov.au/EDMS/Projects/6715 EWR Planning and Impementation/Final Seasonal Watering Proposal Wimmera River System 2020-21.docx

Walker, K., (2017) Connecting culture to water management Feasibility study into pilot watering project at the Ranch Billabong, Dimboola, Assignment prepared as part of the Graduate Certificate of Catchment and Waterway Management, Wimmera CMA, Horsham.

Wimmera CMA (2014), Wimmera Waterway Strategy 2014-2022, Wimmera CMA, Horsham

Wimmera CMA (2015), Environmental Water Management Plan – Wimmera River System. Wimmera CMA, Horsham.

Mt William Creek Refuge Pool at Mokepilly February (above) and March (below) 2020

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Appendix 1: Media Information Regarding Environmental Water Releases

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Appendix 2: Environmental Flow Recommendations Table 1. Environmental objectives and flow components for the Wimmera River Reaches 2 and 3. Compliance Point – Wimmera River @ Horsham (415200). Is this flow component Flow consistent with the Timing Magnitude Climatic scenario Frequency Duration Associated environmental objective component environmental flow study? Include source. DROUGHT Less than 21 days in total Ensure stress on environmental values is not Cease to DRY As infrequently as exacerbated beyond natural. Cease to flow periods Dec-May 0 ML/d Yes (Alluvium 2013) Flow possible should be completed with fresh lasting at least 7 days

Less than 7 days in total duration. AVERAGE Maintain edge habitats in deeper pools and runs, and shallow water habitat availability for 10 ML/d macroinvertebrates and endemic fish. Yes (Alluvium 2013) Dec -May ALL Continuous Continuous or natural Maintains near permanent inundated stream channel for riparian vegetation and to prevent excessive in Baseflow stream terrestrial growth. Prevent terrestrialisaton of the lower banks from June- Continuous Continuous invasive phragmites and provide increased flow and 100 ML/d Yes (Alluvium 2013) Nov ALL variability to support fish movement and diversity of habitat. Dec - DROUGHT 2 per period 3 - 7 days Periodically improving water quality by flushing pools 35-40 ML/d Yes (Alluvium 2013) May DRY during low flows.

2 per period Provide variable flow during low flow season for AVERAGE 2 - 7 days macroinvertebrates (over wood debris to increase Dec -May 100 ML/d Yes (Alluvium 2013) biofilm abundance as a food source), fish movement WET 3 per period and to maintain water quality and diversity of habitat.

Freshes DROUGHT 1 per period 1 day Provide variable flow during high flow season for fish June - DRY 3 per period 2 days movement and to maintain water quality and diversity 400 ML/d Yes (Alluvium 2013) Nov AVERAGE 5 per period 3 days of habitat. Also flushes surface sediments from hard substrates for macroinvertebrates. WET 5 per period 4 days DRY 1 per period 1 day Wets benches, entraining organic debris and June - 1,300 ML/d AVERAGE 2 per period 2 days promoting diversity of habitat. Yes (Alluvium 2013) Nov WET 3 per period 3 days

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AVERAGE 1 per period 2 days Disturbs algae/bacteria/organic biofilm present on June - rock or wood debris for macroinvertebrates. Wets 2,600 ML/d Yes (Alluvium 2013) Nov higher benches, entraining organic debris and WET 2 per period 3 days promoting diversity of habitat.

1 per period or AVERAGE natural Inundate riparian vegetation to maintain condition and facilitate recruitment. Entrain organic debris in the Bankfull Any 4,000 ML/d 2 days Yes (Alluvium 2013) channel to support macroinvertebrates. Maintain

1 per period structural integrity of channel. WET

Inundate floodplain to maintain condition of adults and

Aug-Nov facilitate recruitment. Entrain organic debris from the Overbank 8,000 ML/d 1 per period 1 day Yes (Alluvium 2013) floodplain to support macroinvertebrates. Maintains WET floodplain geomorphic features.

Table 2. Environmental objectives and flow components for the Wimmera River Reach 4. Compliance Point- Wimmera River @ Lochiel Railway Bridge (415246). Is this flow component Flow consistent with the Timing Magnitude Climatic scenario Frequency Duration Associated environmental objective component environmental flow study? Include source. DROUGHT Less than 21 days in As infrequently Limits cease to flow to ensure stress on total Cease to flow Dec-May 0 ML/d DRY as possible environmental values is not exacerbated Yes (Alluvium 2013) Less than 7 days in beyond the point of return. AVERAGE total Maintain edge habitats in deeper pools and runs, and shallow water habitat availability 15 ML/d or for macroinvertebrates and endemic fish. Dec-May natural ALL Continuous Continuous Maintains near-permanent inundated stream Yes (Alluvium 2013)

Baseflow channel for riparian vegetation and to prevent excessive in stream terrestrial species growth. 30 ML/d ALL Continuous Continuous Provides flow variability to maintain diversity Jun-Nov Yes (Alluvium 2013) of habitats. DROUGHT Prevent water quality decline by flushing 1 per period pools during low flows. Provide variable flow Freshes Dec -May 70 ML/d DRY 2-7days during low flow season for Yes (Alluvium 2013) 2 per period macroinvertebrates (over wood debris to AVERAGE increase biofilm abundance as a food

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Is this flow component Flow consistent with the Timing Magnitude Climatic scenario Frequency Duration Associated environmental objective component environmental flow study? Include source. source), fish movement and to maintain WET 3 per period water quality and diversity of habitat. DROUGHT 1 per period 1 day Increase the baseflow water depth by to provide stimulus for fish movement (not DRY 3 per period 2 days required in drought years, frequently required June -Nov 70 ML/d Yes (Alluvium 2013) AVERAGE 5 per period 3 days in wet years). Provide flow variability to maintain water quality and diversity of fish WET 5 per period 4 days habitats. DRY 1 per period 1 day Wets lower benches, entraining organic June - Nov 200 ML/d AVERAGE 2 per period 2 days Yes (Alluvium 2013) debris and promoting diversity of habitat. WET 3 per period 3 days Flush surface sediments from hard 1 per period 2 days AVERAGE substrates to support macroinvertebrates. June - Nov 1300 ML/d Yes (Alluvium 2013) Wets higher benches, entraining organic 2 per period 3 days WET debris and promoting diversity of habitat.

Inundate riparian vegetation to maintain 1 per period, or AVERAGE condition and facilitate recruitment. Entrain natural Bankfull Any 2,000 ML/d 2 days organic debris in the channel to support Yes (Alluvium 2013) macroinvertebrates. Maintain structural WET 1 per period integrity of channel.

Inundate floodplain vegetation to maintain condition and facilitate recruitment. Entrain 1 per period or Overbank Aug-Nov 6,000 ML/d WET 1day organic debris from the floodplain to support Yes (Alluvium 2013) natural macroinvertebrates. Maintains floodplain geomorphic features.

Table 3. Environmental objectives and flow components for MacKenzie River Reach 1 and 2. Compliance Point: Not present. Is this flow component Flow consistent with the Timing Magnitude Climatic scenario Frequency Duration Associated environmental objective component environmental flow study? Include source. Less than 80 days in As infrequently Ensure stress on environmental values is not Cease to Flow Dec -May 0 ML/d DROUGHT total Yes (Alluvium 2013) as possible exacerbated beyond natural. Cease to flow DRY

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Is this flow component Flow consistent with the Timing Magnitude Climatic scenario Frequency Duration Associated environmental objective component environmental flow study? Include source. periods should be completed with fresh Less than 30 days in AVERAGE lasting at least 7 days duration. Yes (Alluvium 2013) total

Maintain edge habitats in deeper pools and runs, and shallow water habitat availability 2 ML/d ALL for macroinvertebrates and endemic fish. Dec -May Continuous Continuous Yes (Alluvium 2013) or natural Maintains near-permanent inundated stream Baseflow channel to prevent excessive in stream

terrestrial species growth.

Facilitate annual dispersal of juvenile June - Nov 27 ML/d ALL Continuous Continuous platypus into the Wimmera River. Provides Yes (Alluvium 2013) flow variability to maintain diversity of habitat. DROUGHT 3 per period 4-7 days Prevent water quality decline by flushing Dec -May 5 ML/d Yes (Alluvium 2013) DRY 4 per period 4-7 days pools during low flows.

AVERAGE 2 per period 2-7 days Provide variable flow during low flow season for macroinvertebrates (over wood debris to Dec -May 50 ML/d increase biofilm abundance as a food Yes (Alluvium 2013) source), fish movement and to maintain WET 3 per period 2-7 days water quality and diversity of habitat.

Freshes DROUGHT 5 per period 2 days DRY 5 per period 4 days Flush surface sediments from hard June- Nov 55 ML/d substrates to support macroinvertebrates. Yes (Alluvium 2013) AVERAGE 5 per period 5 days WET 5 per period 7 days

1 per period 1 days Increase the baseflow water depth by to DROUGHT provide stimulus for fish movement (not required in drought years, frequently required June-Nov 130 ML/d DRY 3 per period 2 days Yes (Alluvium 2013) in wet years). Provide flow variability to AVERAGE 5 per period 3 days maintain water quality and diversity of fish WET 5 per period 4 days habitats. Inundate riparian vegetation to maintain

Bankfull Any 500 ML/d 1 per period 2 days condition and facilitate recruitment. Entrain Yes (Alluvium 2013) AVERAGE organic debris in the channel to support

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Is this flow component Flow consistent with the Timing Magnitude Climatic scenario Frequency Duration Associated environmental objective component environmental flow study? Include source. macroinvertebrates. Maintain structural WET 1 per period 2 days integrity of channel.

Inundate floodplain vegetation to maintain condition and facilitate recruitment. Entrain Overbank Aug-Nov 900 ML/d WET 1 per period 1 day organic debris from the floodplain to support Yes (Alluvium 2013) macroinvertebrates. Maintains floodplain geomorphic features.

Table 4. Environmental objectives and flow components for MacKenzie River Reach 3. Compliance Point: MacKenzie River @ McKenzie Creek Reserve (415251). Is this flow component Flow consistent with the Timing Magnitude Climatic scenario Frequency Duration Associated environmental objective component environmental flow study? Include source.

DROUGHT Less than 80 days in Ensure stress on environmental values is not As infrequently total exacerbated beyond the point of no return. Cease to Flow Dec-May 0 ML/d as possible Yes (Alluvium 2013) Cease to flow periods should be completed

DRY Less than 30 days in with fresh lasting at least 7 days duration. total AVERAGE

Maintain edge habitats and shallow water habitat availability for macroinvertebrates 10ML/d and endemic fish and near-permanent Baseflow Any ALL Continuous Continuous Yes (Alluvium 2013) or natural inundated stream channel for riparian vegetation and prevents excessive instream terrestrial species growth. DROUGHT 3 per period 2-7 days Provide variable flow during low flow season DRY 3 per period 3-7 days for macroinvertebrates (over wood debris to Dec - May 35 ML/d increase biofilm abundance as a food Yes (Alluvium 2013) AVERAGE 4 per period 3-7 days source), fish movement and to maintain Freshes water quality and diversity of habitat. WET 4 per period 3-7 days

DROUGHT 2 days Stimulate fish movement and maintain water Jun-Nov 35ML/d 5 per period Yes (Alluvium 2013) DRY 4 days quality and diversity of habitat.

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Is this flow component Flow consistent with the Timing Magnitude Climatic scenario Frequency Duration Associated environmental objective component environmental flow study? Include source. AVERAGE 5 days WET 7 days

1 day Achieve shear stress to flush surface AVERAGE Jun-Nov 190 ML/d 1 per period sediments from hard substrates to support Yes (Alluvium 2013)

2 days macroinvertebrates. WET Inundate riparian vegetation to maintain condition and facilitate recruitment (including 1 per period, or Callistemon Wimmerensis). Entrain organic Bankfull Any 500 ML/d WET 1-day Yes (Alluvium 2013) natural debris in the channel to support macroinvertebrates. Maintain structural integrity of channel. Inundate floodplain vegetation to maintain condition and facilitate recruitment (including 1 per period, or Callistemon Wimmerensis). Entrain organic Overbank Aug-Nov 1000 ML/d WET 1 day Yes (Alluvium 2013) natural debris in the channel to support macroinvertebrates. Maintains floodplain geomorphic features.

Table 5. Environmental objectives and flow components for Lower Mt William Creek (below Lake Lonsdale). Compliance Point: Mt William Creek at Lake Lonsdale Tail gauge (415203). Is this flow component Flow consistent with the Timing Magnitude Climatic scenario Frequency Duration Associated environmental objective component environmental flow study? Include source. Less than 90 days in DROUGHT total Ensure stress on environmental values is not As infrequently exacerbated beyond the point of no return. Cease to Flow Dec -May 0 ML/d as possible Yes (Alluvium 2013) Cease to flow periods should be concluded DRY Less than 30 days in with fresh lasting at least 7 days duration. AVERAGE total Maintain edge habitats and shallow water habitat availability for macroinvertebrates 5 ML/d and endemic fish and near-permanent Baseflow Any All Continuous Continuous Yes (Alluvium 2013) or natural inundated stream channel for riparian vegetation and prevents excessive instream terrestrial species growth.

Freshes Dec-May 20 ML/d DROUGHT 3 per period 2-7 days Yes (Alluvium 2013)

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Is this flow component Flow consistent with the Timing Magnitude Climatic scenario Frequency Duration Associated environmental objective component environmental flow study? Include source. Prevent water quality decline by flushing DRY 3 per period 4-7 days pools during low flows.

AVERAGE 3 per period 2-7 days Provide variable flow during low flow season for macroinvertebrates (over wood debris to Dec -May 30 ML/d increase biofilm abundance as a food source), fish movement and to maintain WET 3 per period 3-7 days water quality and diversity of habitat. Yes (Alluvium 2013)

DROUGHT 1 per period 3 days Wets benches, entraining organic debris and

promoting diversity of habitat. Flush surface sediments from hard substrates to support June-Nov 100 ML/d DRY 3 per period 3 days Yes (Alluvium 2013) macroinvertebrates. Wets low benches, AVERAGE 3 per period 5 days entraining organic debris and promoting diversity of habitat. WET 5 per period 7 days DRY 1 per period 1 days Wets highest benches, entraining organic Jun-Nov 500 ML/d AVERAGE 2 per period 2 days Yes (Alluvium 2013) debris and promoting diversity of habitat WET 3 per period 2 days

1 per year or Inundate riparian vegetation to maintain AVERAGE 2 days natural condition and facilitate recruitment. Entrain Bankfull Any 750 ML/d organic debris in the channel to support Yes (Alluvium 2013) macroinvertebrates. Maintain structural WET 1 per year 4 days integrity of channel. Inundate floodplain vegetation to maintain condition and facilitate recruitment. Entrain Overbank Aug - Nov 1,500 ML/d WET 1 per year 1 day organic debris from the floodplain to support Yes (Alluvium 2013) macroinvertebrates. Maintains floodplain geomorphic features.

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Table 6. Environmental objectives and flow components for Upper Mt William Creek (above Lake Lonsdale). Compliance Point: Mt William Creek @ Mokepilly (415252). Is this flow component consistent with the Flow Timing Magnitude Climatic scenario Duration Associated environmental objective environmental flow study? Include component source. Cease to 90 days Provides a physical to the exposed river channel. Dec-May 0 ML/d 1 per period Yes (SKM 2005) Flow maximum Leads to an increase in macroinvertebrate species diversity. Minimum 24 Improve water quality in pools, provides access to habitat for Baseflow June-Nov Continuous Continuous Yes (SKM 2005) ML/d fish and macroinvertebrates Prevents sediment accumulation that can smother habitat. Assists in maintaining and access to suitable habitat for macroinvertebrate and fish species. Assists in maintenance of Dec –May > 1 ML/d 2 per year 5 days wetted channel during summer low flow period and improves water quality in pools. Triggers spawning in many Western Carp Gudgeon as well as a number of other key native fish species. Freshes Provides disturbance to macroinvertebrate communities which Yes (SKM 2005) June- increases abundance and diversity in native fish species and >52 ML/d 4 per year 7 days November triggers spawning in Western Carp Gudgeon. Improves water quality in pools. Transport the sediment downstream to prevent the smothering Winter- of key habitats. Flushed fine sediment and organic material >500 ML/d 2 per year 2 days Spring from pools. Reduces vegetation encroachment in to channel and disturbs terrestrial vegetation on bank.

Table 7. Environmental objectives and flow components for Bungalally Creek. Compliance Point: Not Present. Is this flow component consistent Flow component Timing Magnitude Climatic scenario Frequency Duration Associated environmental objective with the environmental flow study? Include source.

AVERAGE Inundate riparian vegetation to maintain condition 1 per period or Bankfull Any 60 ML/d 2 days and facilitate recruitment. Maintain structural Yes (Alluvium 2013) natural WET integrity of channel.

Inundate floodplain vegetation to maintain condition 1 per period or Overbank Aug-Nov 150 ML./d WET 1 days and facilitate recruitment. Maintains floodplain Yes (Alluvium 2013) natural geomorphic features.

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Table 8. Environmental objectives and flow components for Burnt Creek Reach 1 (upper Burnt Creek). Compliance Point: Burnt Creek at Wonwondah East (415223). Is this flow component consistent with the Flow component Timing Magnitude Climatic scenario Frequency Duration Associated environmental objective environmental flow study? Include source. Less than 80 DROUGHT days in total Ensure stress on environmental values is not As infrequently exacerbated beyond the point of no return. Cease to Flow Dec-May 0 ML/d as possible Yes (Alluvium 2013) DRY Less than 30 Cease to flow periods should be concluded with

days in total fresh lasting at least 7 days duration. AVERAGE

Maintain edge habitats and shallow water habitat availability for fish and macroinvertebrates and 1 ML/d Baseflow All year ALL Continuous Continuous inundated stream channel for riparian vegetation Yes (Alluvium 2013) or natural and prevents excessive instream terrestrial growth. DROUGHT 3 per period 2-7 days Prevent water quality decline by flushing pools DRY 3 per period 4-7 days Dec - May 30 ML/d during low flows. AVERAGE 3 per period 2-7 days

WET 3 per period 3-7 days DROUGHT 1 per period 3 days Provide variable flow for fish movement and DRY 3 per period 3 days diversity of habitat. Also flushes surface Freshes Jun-Nov 55 ML/d Yes (Alluvium 2013) sediments from hard substrates for AVERAGE 5 per period 5 days macroinvertebrates. WET 5 per period 7 days DRY 1 per period 1 day Disturb the algae/bacteria/organic biofilm May - Jun 160 ML/d AVERAGE 2 per period 2 days present on rock or wood debris to support

WET 3 per period 3 days macroinvertebrate communities.

Inundate riparian vegetation to maintain AVERAGE condition and facilitate recruitment. Entrain 1 per period, or Bankfull Any 400 ML/d 2 days organic debris in the channel to support Yes (Alluvium 2013) natural macroinvertebrates. Maintain structural integrity WET of channel.

Inundate floodplain vegetation to maintain condition and facilitate recruitment. Entrain Aug-Nov 1,000 ML/d WET 1 per year 1 day Overbank organic debris from the floodplain to support Yes (Alluvium 2013)

macroinvertebrates. Maintains floodplain geomorphic features.

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Table 9. Environmental objectives and flow components for Burnt Creek Reach 2 (lower Burnt Creek). Compliance Point: Not Present. Is this flow component consistent with the Flow component Timing Magnitude Climatic scenario Frequency Duration Associated environmental objective environmental flow study? Include source.

AVERAGE Inundate riparian vegetation to maintain condition and 45 ML/d 1 per period, or facilitate recruitment. Entrain organic debris in the Bankfull Any 2 days Yes (Alluvium 2013) or natural natural channel to support macroinvertebrates. Maintain WET structural integrity of channel.

Inundate floodplain vegetation to maintain condition and Aug - 1 day facilitate recruitment. Entrain organic debris from the Overbank 90 ML/d WET 1 per period Yes (Alluvium 2013) Nov floodplain to support macroinvertebrates. Maintains floodplain geomorphic features.

Table 10. Environmental objectives and flow components for Dock Lake Compliance Point: Not Present. Is this flow component consistent with the Flow component Timing Magnitude Climatic scenario Frequency Duration Associated environmental objective environmental flow study? Include source. 1 in 2 years (WET) Between 271 Inundation (partial 1 in 3-4 years 3 to 14 Wetland vegetation and bird life cycles with ancillary Any ML and 973 DRY/AVERAGE/WET Yes (Jacobs 2015) fill) (AVE) months benefits for frogs, macroinvertebrates and turtles ML 1 in 5 years (DRY)

Appendix 3: Flow components that have been delivered from 2005 to 2018. Hydrological achievement of flow components over time Reach Flow Component 06-07 07-08 08-09 09-10 10-11 11-12 12-13 13-14 14-15 15-16 16-17 17-18 18-19 19-20

Summer autumn baseflows 4 Wimmera River E/U E/U E/U E/U E/U E/U E/U E/U E/U E E E E 15 ML/d

U Winter spring baseflows 4 Wimmera River U U U U E/U E/U E/U E/U E/U U U E/U E 30 ML/d

Summer-autumn freshes 4 Wimmera River E/U E/U E/U E/U E/U E/U E/U E/U E/U E E E E 70 ML/d x 1-3 x 2-7 d

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Hydrological achievement of flow components over time Reach Flow Component 06-07 07-08 08-09 09-10 10-11 11-12 12-13 13-14 14-15 15-16 16-17 17-18 18-19 19-20

Winter-spring freshes 4 Wimmera River U U U U E/U E/U E/U E/U E/U U U U/E E U 70 ML/d x 1-5 x 1-4 d Summer autumn, 2 MacKenzie baseflows E/U/O E/U/O E/U/O E/U/O E/U/O E/U/O E/U/O E/U/O E/U/O E/O E E E E River 2 ML/d 2 MacKenzie Winter spring baseflows U U U U E/U/O E/U/O E/U/O E/U/O E/U/O U/O U U/E E U River 27 ML/d 2 MacKenzie Summer-autumn freshes E/U E/U E/U E/U E/U E/U E/U E/U E/U E E E E E River 5 to 50 ML/d x 2-4 x 2-7 d 2 MacKenzie Winter-spring freshes U U U U E/U E/U E/U E/U E/U U U U/E E U River 55 ML/d x 5 x 2-7d 2 MacKenzie Winter-spring freshes U U U U E/U E/U E/U E/U E/U U U U River 130 ML x 1-5 x 1-4 d Summer, autumn, Winter, 3 MacKenzie spring baseflows E/U E/U E/U E/U E/U E/U E/U E/U E/U U/E E/U E River 10 ML/d 3 MacKenzie Summer-autumn freshes U U U U E/U E/U E/U E/U E/U E E E River 35 ML/d x 3-4 x 2-7 d 3 MacKenzie Winter-spring freshes U U U U E/U E/U E/U E/U E/U U U U/E River 35 ML/d x 5 x 2-7 d Summer, autumn, Winter, Lower Mt William spring baseflows E/U E/U E/U E/U E/U E/U E/U E/U E/U U E/U E E E 5 ML/d Summer-autumn freshes Lower Mt William E/U E/U E/U E/U E/U E/U E/U E/U E/U E E E E 20-30 ML x 3 x 2-7 d Winter-spring freshes Lower Mt William E/U E/U E/U E/U E/U E/U E/U E/U E/U U U E 100-500 ML/d x 1-5 x 1-7d Upper Mt William Summer-autumn baseflows U U U U U/E U/E U/E U/E E/U E/U U U E E Creek 500 ML/total Summer autumn Winter- Upper Burnt spring baseflows E/U/O E/U/O E/U/O E/U/O E/U/O E/U/O E/U/O E/U/O E/U/O E/O/U E/U E/U E E Creek 1 ML/d Upper Burnt Summer-autumn freshes E/U E/U E/U E/U E/U E/U E/U E/U E/U E E E E Creek 30 ML/d x 3 x 2-7d Upper Burnt Winter-spring freshes U U U U U U/E E/U E/U E/U O/U U U U U Creek 55 ML/d x 1-5 x 3-7d Upper Burnt Autumn-winter freshes U U U U U U/E U U U O/U U U Creek 160 ML/d x 1-3 x 1-3d

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Hydrological achievement of flow components over time Reach Flow Component 06-07 07-08 08-09 09-10 10-11 11-12 12-13 13-14 14-15 15-16 16-17 17-18 18-19 19-20 Lower Burnt Winter-spring freshes U U U U U U E/U E/U E/U U U Creek 45ML/d x1 x 2d Winter-spring freshes Bungalally Creek U U U U U U E/U E/U E U U 60 ML/d x 1 x 2d

Key for Table.

No significant part of the flow component achieved Flow component partially achieved Flow component has been completely achieved, i.e. complete duration, frequency and magnitude was achieved

E Managed environmental water release O Consumptive water en route/other managed flow U Unregulated flows X Unknown

Appendix 4: Priority Watering Actions

Table 11. Priority Watering Actions Wimmera Reach 4. Volume PWA Target Flow function Priority Rationale (ML) Salinity levels in the lower Wimmera River reach 50,000 µS/cm during cease to flow Maintain edge habitats in deeper pools and runs, conditions. This flow component plays a critical role in maintaining water quality for and shallow water habitat availability for Baseflow aquatic and riparian ecosystems. This flow mitigates severe salinity impacts so reduces macroinvertebrates and endemic fish. Maintains Dec-May Very High likelihood of fish kills, algae blooms and die back of fringing vegetation and 9,100 ML near-permanent inundated stream channel for 15 ML/day macroinvertebrates which were common events during the 2002 to 2010 when there riparian vegetation and to prevent excessive in were long cease to flow periods. This baseflow also supports vegetation in low stream terrestrial species growth. benches. It is of high importance to maintain constant baseflows in the lower Wimmera River during winter and spring when there are periods of low rainfall. Salinity levels in the Baseflow lower Wimmera River reach 50,000 uS/cm during cease to flow conditions. This flow Provides flow variability to maintain diversity of June-Nov Very High component plays a critical role in maintaining water quality for aquatic and riparian 10,980 ML habitats. 30 ML/day ecosystems. This flows diminish the high risk of die back of vegetation and fish fills which were common events during the 2002 to 2010 when there were long cease to flow periods.

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Volume PWA Target Flow function Priority Rationale (ML)

Salinity levels in the lower Wimmera River reach 50,000 uS/cm during cease to flow Prevent water quality decline by flushing pools Freshes conditions. This flow component plays a critical role in freshening the water quality during low flows. Provide variable flow during low Dec-May, during very hot period of the year where evaporation and seepage levels are high and flow season for macroinvertebrates (over wood Very High 150 – 1575 1-3 events of baseflows are not able to prevent water quality decline in refuge pools. These freshes debris to increase biofilm abundance as a food ML 70 ML/day maintain water quality for aquatic and riparian ecosystems. These freshes diminish the source), fish movement and to maintain water 2-7 days high risk of algal blooms, die back of vegetation and fish fills which were common quality and diversity of habitat. events during the 2002 to 2010 when there were long cease to flow periods.

Increase the baseflow water depth by to provide Freshes - stimulus for fish movement (not required in drought This flow component plays a critical role in freshening the water quality during winter smaller years, frequently required in wet years). Provide and spring periods when there is low rainfall. These freshes are useful when baseflows June-Nov Very High 60 – 1200 flow variability to maintain water quality and diversity are not able to prevent water quality decline. These freshes provide flow variability to 1-5 events of ML of fish habitats. stimulate fish movement and maintain a healthy water quality for aquatic and riparian 70 ML/day Wets lower benches, entraining organic debris and ecosystems. 1-4 days promoting diversity of habitat. Freshes - medium Provide variable flow during high flow season for June-Nov fish movement and to maintain water quality and 130 – 1170 Medium Wet lower benches, entraining organic debris and promoting diversity of habitat 1-3 events of diversity of habitat. Also flushes surface sediments ML 200 ML/day from hard substrates for macroinvertebrates 1-3 days

Inundation of Provide water to disconnected anabranch of Provides cultural outcomes given the significance of the site and also some riparian and Ranch High 20 ML Wimmera River at Dimboola via pumping aquatic vegetation outcomes (e.g. Common Sneezeweed). Billabong

Table 12. Priority Watering Actions MacKenzie River Reach 3. Rationale Volume PWA Target Flow function Priority (ML) Maintain edge habitats and shallow water habitat availability for macroinvertebrates and endemic fish Baseflow all and near-permanent inundated stream channel for High (Very Prevents reach 2 and reach 3 from drying out completely and loss of high value fish and year 10 riparian vegetation and prevents excessive instream High June- platypus communities. Lack of flows would see it dry out in a few weeks thereby losing 8210 ML ML/day terrestrial species growth. Facilitate annual November) a high value fish community and opportunities for fish movement/dispersal. dispersal of juvenile platypus into the Wimmera River.

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Rationale Volume PWA Target Flow function Priority (ML) Freshes Provide variable flow during low flow season for December- macroinvertebrates (over wood debris to increase May High This watering action benefits native fish movement and macroinvertebrate heath and 300 – 1400 biofilm abundance as a food source), fish movement 3-4 events of maintenance of water quality and dispersal of the very high value platypus population. ML and to maintain water quality and diversity of 35 ML/day habitat. 2-7 days Freshes June- November Stimulate fish movement and maintain water quality Very High This watering action benefits native fish movement and macroinvertebrate heath and 350 – 1225 5 events of and diversity of habitat. maintenance of water quality and diversity of habitat. ML 35 ML/day 2-7 days

Table 13. Priority Watering Actions MacKenzie River Reach 2. PWA Rationale Volume Flow function Priority Target (ML)

Maintain edge habitats in deeper pools and runs, and This reach of Mackenzie River supports the source population of indigenous fish (River Baseflow shallow water habitat availability for macroinvertebrates Blackfish, Mountain Galaxias, Flathead Gudgeon, Southern Pygmy Perch) and a Dec-May 950 ML and endemic fish. Maintains near-permanent inundated Very High population of platypus that are regionally important. This watering action prevents this 2 ML/day stream channel to prevent excessive in stream terrestrial reach from drying out completely and loss of high value fish and platypus communities. species growth. Baseflow Facilitate annual dispersal of juvenile platypus into the June-Nov Whilst these flows are typically generated through pickup, if it is a dry winter spring Wimmera River. Provides flow variability to maintain High 5,490 ML 27 there’s still a risk that it could dry out in parts. diversity of habitat. ML/day Freshes Prevent water quality decline by flushing pools during low Dec-May flows. 2-4 Smallish volume has typically meant it has been delivered with baseflows to get the full Provide variable flow during low flow season for 120 – 1260 events of Very High suite of flow for the reach. This watering action prevents water quality decline and macroinvertebrates (over wood debris to increase biofilm ML 5-50 supports fish movement. This watering action is important to reduce salinity levels and abundance as a food source), fish movement and to ML/day vegetation diversity on banks. maintain water quality and diversity of habitat. 2-7 days Freshes Provide variable flow during low flow season for June-Nov macroinvertebrates (over wood debris to increase biofilm 5 events abundance as a food source), fish movement and to Provides some variation of flow to encourage fish movement, healthy macroinvertebrate 250 - 875 of maintain water quality and diversity of habitat. High communities, maintains water quality and mobilisation of sediment. ML 55 Flush surface sediments from hard substrates to support ML/day macroinvertebrates. 2-7 days

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Table 23. Priority Watering Actions Upper Burnt Creek. PWA Volume Flow function Priority Rational Target (ML) Maintain edge habitats and shallow water habitat Baseflow all availability for fish and macroinvertebrates and year 1 Very High This watering action is critical for supporting a good native fish community as well as 1,825 ML inundated stream channel for riparian vegetation and ML/day Western Swamp Crayfish. prevents excessive instream terrestrial growth. Fresh Dec- May 3 Prevent water quality decline by flushing pools during Very High 270 - 945 events of This watering action provides good vegetation, macroinvertebrates and native fish low flows ML 30 ML/day outcomes. 2-7 days Provide variable flow for fish movement and diversity Fresh Jun- of habitat. Also flushes surface sediments from hard Nov 1-5 substrates for macroinvertebrates. Very High This watering action provides good vegetation, macroinvertebrates and native fish 180 – 2100 events of Disturb the algae/bacteria/organic biofilm present on outcomes. ML 55 ML/day rock or wood debris to support macroinvertebrate 3-7 days communities. Fresh May- Jun 1-3 Disturb the algae/bacteria/organic biofilm present on This watering action provides good vegetation, macroinvertebrates and native fish 160 - 1440 events of rock or wood debris to support macroinvertebrate Medium outcomes. ML 160 ML/day communities. 1-3 days

Table 15. Priority Watering Actions Lower Burnt Creek. Rational Volume PWA Target Flow function Priority (ML)

Bankfull Inundate riparian vegetation to maintain condition and This watering action is critical for supporting a good fish community as well as Western Any month 1 facilitate recruitment. Entrain organic debris in the Swamp Crayfish. event of 45 High 300 ML channel to support macroinvertebrates. Maintain ML/d for 2 structural integrity of channel. days Overbank Inundate floodplain vegetation to maintain condition Aug-Nov 1 This watering action provides good vegetation, macroinvertebrates and native fish and facilitate recruitment. Entrain organic debris from event of 90 Medium outcomes. 180 ML the floodplain to support macroinvertebrates. ML/d for 1 Maintains floodplain geomorphic features. day

Table 16. Priority Watering Actions Bungalally Creek. PWA Rationale Volume Flow function Priority Target (ML)

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Bankfull Bungalally Creek has valuable riparian vegetation in some sections which provides Any time of Inundate to maintain condition of adults important habitat for terrestrial and aquatic species and much like Reach 2 of the Burnt year 1 and facilitate recruitment for riparian EVCs Medium Creek. Due to the high level regulation of this system and the fact that it would only 300 ML event of 60 Maintain structural integrity of channel and prevents receive flows during high flow events, the creek bed will most probably be completely ML/day for loss of channel diversity through lack of flow variability. dry when watering commences. 2 days

Table 17. Priority Watering Actions Upper Mt William Creek. Rationale Volume PWA Target Flow function Priority (ML) Prevents sediment accumulation that can smother Lake Lonsdale levels are reducing following dry conditions in 2017. It is very important habitat. Assists in maintaining and access to to continue to monitor these refuge pools that provide crucial drought refuge to high Fill refuge suitable habitat for macroinvertebrate and fish value native fish populations, Obscure Galaxias, Australian Smelt, Flathead Gudgeon, pools during species. Assists in maintenance of wetted channel short finned eel (rarely) and the ‘vulnerable’ Southern Pygmy Perch, (Biosis 2012), dry conditions Very High 300 ML during summer low flow period and improves water (SKM 2005). (summer/ quality in pools. Triggers spawning in many Western autumn) Carp Gudgeon as well as a number of other key native fish species.

Table 18. Priority Watering Actions Lower Mt William Creek. PWA Rationale Volume Flow function Priority Target The lower Mt William Creek contains high value native fish populations, River Blackfish, Maintain edge habitats and shallow water habitat Mountain Galaxias, Australian Smelt, Flat-headed Gudgeon, short finned eel and the Baseflow availability for macroinvertebrates and endemic fish ‘vulnerable’ Southern Pygmy Perch, (Austral 2015). The absence of flow would place year round and near-permanent inundated stream channel for High 1,825 ML these very high environmental values at risk. River Blackfish have been increasingly 5 ML/day riparian vegetation and prevents excessive instream rare in the sections of the Wimmera catchment outside the Grampians (EnviroDNA terrestrial species growth. 2017a, 2017b). Fresh Prevent water quality decline by flushing pools during Dec-May 3 low flows. events of Provide variable flow during low flow season for Very High This watering action provides a much needed improvement to water quality with a pulse 90 - 525 20 to 30 macroinvertebrates (over wood debris to increase of water reaching the end of the creek which baseflows tend not to be able to do. ML ML/day biofilm abundance as a food source), fish movement 2-7 days and to maintain water quality and diversity of habitat. Fresh Wets benches, entraining organic debris and promoting June-Nov If flow for the Wimmera River is provided from Taylors Lake then these freshes are diversity of habitat. Flush surface sediments from hard 1-5 events Medium important to water the Wimmera River above Taylors. This watering action also 285 - 3325 substrates to support macroinvertebrates. Wets low of provides a dispersal mechanism for high value native fish communities as well as ML benches, entraining organic debris and promoting 100 ML/day vegetation and macroinvertebrate outcomes. diversity of habitat. 1-7 days

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Table 19. Priority Watering Actions Dock Lake Rationale Volume PWA Target Flow function Priority (ML) Provide low- Provides abundant vegetation response and Aligns with objectives and recommendations in Dock Lake FLOWS Study (Jacobs, level inundation 300 - subsequent bird-breeding events for a number of High 2015). Water provided from unregulated flows/spills in 2016 led to a significant bird- for high quality 1000ML wetland bird species. breeding event and an abundance of wetland birds. wetland habitat

Burnt Creek at Dingley Dell, November 2019

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