River Murray Weekly Report For the week ending Wednesday, 23 December 2020 Trim Ref: D20/51035

Please note that MDBA offices will be closed from Christmas Day to New Year’s Day. As such this will be the final Weekly Report issued for the 2020 calendar year. There will be no Weekly Report issued for the week ending Wednesday, 30th December 2020. The first report for 2021 will cover the two‐week period ending Wednesday, 6th January 2021 and will be available from Friday, 8th January 2021. Rainfall and inflows This week there were widespread and varied rainfall totals across the Murray‐Darling Basin, the highest totals of which were observed in North East NSW (Map 1). In the southern Basin, the highest totals were recorded in the Murrumbidgee catchment, with slightly lower totals in upper Murray catchments and along the mid‐Murray. In NSW, in the Murrumbidgee catchment recorded 64 mm, and in the Central Murray catchment, recorded 53 mm. In Victoria, Falls Creek in the Victorian Alps recorded 39 mm and Kerang in the mid‐Murray recorded 43 mm.

Map 1 ‐ Murray‐Darling Basin rainfall totals for week ending 23 December 2020 (Source: Bureau of Meteorology). Streamflow in the upper Murray catchments experienced a small rise in some locations following some rainfall during the week. However, streamflows have now begun to recede again. Further specific information about flows at key locations can be found at the MDBA’s River Murray data webpage. Up‐to‐date river data for sites in the upper Murray can also be found on BoM’s website and in the Basin Daily River Report at the WaterNSW website. BoM produce 7‐day stream flow forecasts for a number of tributaries including the Ovens and Kiewa Rivers and these are available on their website.

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The Bureau of Meteorology’s (BoM) current 8 day rainfall forecast shows rainfall totals up to 25 mm are likely for the upper Murray over the coming week with some lower totals possible on the mid‐Murray.

Photo 1 – Aquatic vegetation in Reedy Lagoon, Gunbower Forest, as drawdown commences. Credit: GBCMA. River operations

 Water for the environment Southern Spring Flow event concludes  System transfers continue  The delivery of IVT from the Goulburn and Murrumbidgee valleys to the Murray continue  Lake Victoria continues to fall as it supports the delivery of system demands

Water demand The MDBA is actively monitoring shortfall risks. A shortfall occurs when water cannot be delivered to users when and where it is needed. A delivery shortfall occurs when actual water use is higher than it was forecast to be when river water was released from the Hume and Dartmouth storages, weeks earlier, to meet the forecast needs for irrigation and environmental water. A system shortfall occurs when the combined capacity of the system is unable to supply all downstream requirements over the full season. More information about shortfalls can be found at Water demand (shortfalls) | Murray‐Darling Basin Authority (mdba.gov.au). The risk of a delivery shortfall in the River Murray between Junction and the SA Border, over the coming week, is currently negligible. The MDBA is continuing to monitor weather conditions and forecast demands to manage the risk of delivery shortfall. The risk of a system shortfall is being closely monitored in consultation with states. The system is finely balanced and the potential for a system shortfall in late summer has been identified within river operations planning scenarios. The MDBA and states will continue to monitor this risk closely over the coming weeks and will take steps to minimise the risk of a shortfall as necessary. The MDBA, Basin state governments and their agencies have different roles and responsibilities in managing delivery shortfalls. Read more information on delivery shortfall risks for Victorian water licence holders. Water quality impacts A number of amber alerts for blue‐green algae remain and include the River Murray at Picnic Point, Barham, , , upstream of Euston Weir, Mt Dispersion, Merbein, Curlwaa, Fort Courage and Lock 8, plus the at Old and and the at Stoney Crossing. It is important that water users regularly keep up to date with algal alerts, notices and health warnings. This information is available through Goulburn‐Murray Water and WaterNSW. Following the Bureau of Metrology’s declaration of La Niña and continued wet rainfall outlook across south eastern Australia, Murray Darling Basin communities should be aware there is a significant risk of hypoxic blackwater events occurring particularly in . After three hot and dry years, floodplains have a high load of leaf litter and other organic material. La Niña conditions in summer can increase the risk of heavy rain and flooding, which can wash organic matter into waterways and lead to hypoxic blackwater events. For more information, including the Basin water quality risk map, please see the MDBA website.

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Monthly snapshot of water in the system River Murray communities can now access a monthly point‐in‐time snapshot that shows what proportion of water in the river has been provided for the environment compared with water for towns, industries and irrigators. Every day, water enters the river at different points and for different purposes, including irrigation, town water supply, industries and specific environmental benefits. The monthly snapshot shows in simple terms the volume of flow and the extent to which it comprises water for the environment at five locations—in the River Murray at Yarrawonga and the South Australian border, and in the Murrumbidgee, Goulburn and Darling rivers just upstream of their junction with the Murray. Find out more on Flows in the River Murray system.

River operations Over the past week, MDBA total active storage decreased by 101 GL to 4,665 GL (55% capacity). At Dartmouth Reservoir, the storage level increased by 5 GL to 2,391 GL (62% capacity). The release, measured at Colemans, was increased this week to target 350 ML/day for variability in the Mitta Mitta River. It is expected that the release will remain at around this rate over the next week and into January. This week the Hume Reservoir storage level decreased by 74 GL to 2,029 (68% capacity). The current Hume release is around 13,000 ML/day and will likely remain at around this rate over the next week. The current release rate is supplying consumptive demands and conveyance along the river, as well as slowing the rate of decline of Lake Victoria’s storage volume as we head into summer.

At Lake , the pool level remains within the normal operating range of between 124.6 and 124.9 m AHD. Diversions to averaged around 4,000 ML/day this week. On the Victorian side, diversion into Yarrawonga Main Channel peaked at near 1,100 ML/day before reducing to the current rate of around 900 ML/day. Diversions over the coming week may vary with Christmas day falling mid‐week.

Photo 2 ‐ Kiewa River near the Yackandandah tributary, Kiewa Photo 3 – Kiewa River at Bandiana, Kiewa catchment. catchment. Credit Matt Todhunter. Credit: Tom Zouch.

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This week, the release from Yarrawonga Weir decreased to 8,800 ML/day, within channel capacity, as the water for the environment Southern Spring Flow event concluded. It is anticipated that releases will continue at around 8,800 ML/day to support demands across summer. The water for the environment flows have supported the Murray Cod nesting season, while also increasing lateral connectivity between the River Murray and the Barmah—Millewa Forest. This greater connectivity has been achieved by opening selected regulators in the forest. Together, these actions promote increased productivity in the river and support plants and animals in the forest. All actions associated with water for the environment are tracked and water usage debited from environmental water holder (EWH) accounts.

Photos 4&5 – Ibis nest with eggs and chick at Boals Deadwood Wetland, Barmah Forest (above) and Pseudorpahis spinescens (Moira Grass) on flooded Hut Lake, Barmah Forest (below). Credits: Keith Ward, GBCMA.

Flow through the Edward River Offtake remains steady near 1,550 ML/day, while flow through the Gulpa Creek Offtake has averaged near 400 ML/day to help fill wetlands adjacent to the creek. Downstream, return flows from Millewa Forest to the Edward River are gradually easing as flows downstream of Yarrawonga reduce. Flow through the Wakool River, Yallakool Creek and Colligen Creek offtakes is currently around 80, 520 and 270 ML/day, respectively. This week a pulse of water for the environment was delivered in the Yallakool Creek to support silver perch breeding. The flow is anticipated to peak at around 550 ML/d during the coming week. This week the flow downstream of Stevens Weir averaged around 2,500 ML/day and is anticipated to remain near this rate over the coming week. On the Goulburn River, the flow measured at McCoys Bridge averaged around 1,100 ML/day over the week and is forecast to fluctuate around 1,350 ML/day throughout the remainder of December as Goulburn Inter Valley Trade (IVT) is delivered to the Murray. In addition to the Goulburn River, the delivery of water from the Goulburn IVT account to the Murray is continuing to take place via the Campaspe River and Broken Creek. A total of around 27 GL was delivered during November and a further 40 GL is to be delivered in December. For more information see the Goulburn‐Murray Water website. Information regarding opportunities for allocation trade between the Goulburn and Murray Valleys is available at the Victorian water register website. Diversions to National Channel averaged around 1,250 ML/day and may reduce slightly over the coming week.

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Photos 6&7 – MDBA Executive Director River Management, Andrew Reynolds with Murray Medal recipients Alan Williams (on the left in photo 6) and Tony Beamish (on the left in photo 7). During the week, MDBA Executive Director River Management, Andrew Reynolds, travelled to Victoria to present River Murray Medals to Alan Williams (photo 6) and Tony Beamish (photo 7). Alan and Tony have both made a significant contribution to the management of the River Murray throughout their long‐standing careers with Goulburn‐Murray Water (GMW). Tony spent around 38 years with GMW, with the past 25 years on the River Murray, initially as a storage operator at Yarrawonga Weir, and then as GMW Unit Coordinator for the Murray Program. Tony has done an enormous amount to link operations staff and the technical/management teams through a lot of difficult change. Alan spent his entire 38‐year career with GMW as weir keeper at Torrumbarry Weir. Notably, in the early 2000s, Alan created an initial design for a carp separation cage which aimed to help mitigate the serious threat that this invasive species posed to the natural ecosystem biodiversity of the mid‐Murray River. Prototype carp separation cages were subsequently made and named “Williams’ cages.” The cages use an innovative design to allow native fish to pass through, while using the jumping behaviour of the carp to trap them. The concept of the Williams’ cage continues to be applied in many locations along the River Murray today. This week inflow from the , measured at , averaged near 2,100 ML/day and is forecast to gradually decrease over the coming week. The Murrumbidgee IVT balance is open for trade from the Murray to the Murrumbidgee (84 GL) but remains closed for trade from the Murrumbidgee to the Murray. MDBA has called 40 GL of Murrumbidgee IVT for the month of December and 45 GL for the month of January. At Euston Weir, the weir pool level remains at FSL. The downstream release averaged around 11,400 ML/day this week and flows are expected to marginally decrease over the coming week. Menindee Lakes storage eased this week to 368 GL (21% capacity). Weir 32 release averaged around 600 ML/day this week and is expected to continue at a similar rate over the coming week. Some water restrictions remain current in NSW. Links to drought services and assistance can be accessed via the MDBA drought webpage. Photo 8 – Lake Victoria photographed from the west, looking east. Credit: SA Water.

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At Wentworth Weir, the weir pool level is being managed at around FSL. The downstream flow averaged near 8,000 ML/day this week and is expected to increase steadily over the coming week. Downstream at Lock 9, Lock 8 and Lock 7 weir pools continue to vary near FSL, within their normal operating range. The storage level at Lake Victoria reduced this week by 26 GL to 439 GL (65% capacity) as water is released to meet system demands. Heading into summer, the storage is anticipated to continue decreasing, as is typical during this higher demand period.

Photo 9 – Lake Victoria outlet regulator. Credit: SA Water.

The flow to South Australia continued to decrease from 12,000 ML/day to around 9,500 ML/day as the water for the environment pulse recedes. Over the coming week flows are forecast to target around 10,000 ML/day. The flow includes South Australia’s normal December Entitlement flow, small volumes of consumptive trade and water for the environment. In December, environmental water holders have extended the spring pulse into SA by trading 40 GL to South Australia. The Lower Lakes 5‐day average water level is 0.83 m AHD. Increased barrage releases will continue to be made when conditions allow to push fresh water into the Coorong and to support Black Bream spawning over the coming months. For information on barrage releases and South Australia’s Entitlement flow, see the South Australian Department for Environment and Water Weekly River Murray Flow Report.

For media inquiries contact the Media Officer on 02 6279 0141 ANDREW REYNOLDS Executive Director, River Management

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Water in Storage Week ending Wednesday 23 Dec 2020 Full Full Current Change in Total Dead Active MDBA Storages Supply Supply Storage Current Storage Storage for the Storage Storage Level Volume Level Week (m AHD) (GL) (m AHD) (GL) % (GL) (GL) (GL) Dartmouth Reservoir 486.00 3 856 460.35 2 391 62% 71 2 320 +5 Hume Reservoir 192.00 3 005 186.58 2 029 68% 23 2 006 -74 Lake Victoria 27.00 677 24.91 439 65% 100 339 -26 Menindee Lakes 1 731* 368 21% (- -) # 0 -7 Total 9 269 5 227 56% - - 4 665 -101 Total Active MDBA Storage 55% ^

Major State Storages Burrinjuck Reservoir 1 026 855 83% 3 852 -14 Blowering Reservoir 1 631 1 434 88% 24 1 410 +20 Eildon Reservoir 3 334 2 239 67% 100 2 139 -17

* Menindee surcharge capacity – 2050 GL ** All Data is rounded to nearest GL ** # NSW has sole access to water when the storage falls below 480 GL. MDBA regains access to water when the storage next reaches 640 GL. ^ % of total active MDBA storage Snowy Mountains Scheme Snowy diversions for week ending 22 Dec 2020 Storage Active Storage (GL) Weekly Change (GL) Diversion (GL) This Week From 1 May 2020 Lake Eucumbene - Total 1 363 n/a Snowy-Murray +1 505 Snowy-Murray Component 673 n/a Tooma-Tumut +7 209 Target Storage 1 510 Net Diversion -6 296 Murray 1 Release +7 762 Major Diversions from Murray and Lower Darling (GL) * New South Wales This Week From 1 July 2020 Victoria This Week From 1 July 2020 Murray Irrig. Ltd (Net) 17.9 301 Yarrawonga Main Channel (net) 6.2 84 Wakool Sys Allowance 2.9 50 Torrumbarry System + Nyah (net) 5.8 136 Western Murray Irrigation 1.1 9 Sunraysia Pumped Districts 3.9 48 Licensed Pumps 8.1 107 Licensed pumps - GMW (Nyah+u/s) n/a 9 Lower Darling 0.1 1 Licensed pumps - LMW 16.6 183 TOTAL 30.1 468 TOTAL 32.5 460 * Figures are derived from actual and estimates where data is unavailable. Please note that not all data may have been available at the time of creating this report. ** All data above is rounded to nearest 100 ML for weekly data and nearest GL for cumulative data

Flow to South Australia (GL) Entitlement this month 217.0 * * Flow to SA will be greater than normal entitlement for Flow this week 73.0 (10 400 ML/day) this month due to environmental flows. Flow so far this month 307.1 Flow last month 370.9

Salinity (EC) (microSiemens/cm at 25o C) Current Average over the last week Average since 1 August 2020 Swan Hill 70 70 100 Euston - - - Red Cliffs 110 100 130 Merbein 110 100 150 Burtundy (Darling) 470 470 340 Lock 9 110 120 130 Lake Victoria 120 120 120 Berri 150 150 160 Waikerie 210 190 210 Morgan 190 190 210 Mannum 220 240 230 Murray Bridge 250 250 240 Milang (Lake Alex.) 680 680 790 Poltalloch (Lake Alex.) 460 470 490 Meningie (Lake Alb.) 1 400 1 460 1 640 Goolwa Barrages 910 950 1 320

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River Levels and Flows Week ending Wednesday 23 Dec 2020 Minor Flood Average Flow this Average Flow last Gauge Height Flow Trend Stage Week Week local (m River Murray (m) (m) AHD) (ML/day) (ML/day) (ML/day) - - - 1 650 F 690 1 670 4.0 1.62 208.14 4 020 R 3 180 3 980 Tallandoon ( Mitta Mitta River ) 4.2 1.53 218.42 820 R 770 660 Heywoods 5.5 3.02 156.65 13 300 F 13 720 11 730 Doctors Point 5.5 2.94 151.41 14 310 S 15 000 12 900 Albury 4.3 1.98 149.42 - - - - 4.6 2.92 128.94 14 180 F 14 300 12 240 Yarrawonga Weir (d/s) 6.4 1.45 116.49 8 790 R 8 850 10 520 6.4 2.02 105.86 8 730 R 9 030 11 070 Torrumbarry Weir (d/s) 7.3 2.65 81.20 7 920 S 8 340 9 110 Swan Hill 4.5 1.64 64.56 9 010 F 9 460 9 270 Wakool Junction 8.8 3.70 52.82 11 350 S 11 320 11 000 Euston Weir (d/s) 9.1 2.05 43.89 11 840 S 11 360 11 090 Mildura Weir (d/s) - - 10 620 F 9 690 10 540 Wentworth Weir (d/s) 7.3 3.11 27.87 9 580 R 8 120 9 640 Rufus Junction - 4.00 20.93 9 910 R 10 060 12 380 Blanchetown (Lock 1 d/s) - 1.00 - 7 750 F 8 320 12 370

Tributaries Kiewa at Bandiana 2.8 1.08 154.31 580 R 660 780 Ovens at Wangaratta 11.9 8.09 145.77 790 F 860 1 220 Goulburn at McCoys Bridge 9.0 1.69 93.11 1 320 R 1 130 1 280 Edward at Stevens Weir (d/s) 5.5 2.43 82.21 2 690 F 2 620 2 410 Edward at Liewah - 2.77 58.15 2 200 S 2 170 2 000 Wakool at Stoney Crossing - 1.47 54.96 590 S 630 680 Murrumbidgee at Balranald 5.0 2.47 58.43 2 190 F 2 170 1 840 Barwon at Mungindi 6.1 2.33 - 0 F 0 0 Darling at Bourke 9.0 3.41 - 0 F 0 0 Darling at Burtundy Rocks - 0.86 - 520 S 530 670

Natural Inflow to Hume 3 460 3 830 (i.e. Pre Dartmouth & Snowy Mountains scheme)

Weirs and Locks Pool levels above or below Full Supply Level (FSL) Murray FSL (m AHD) u/s d/s FSL (m AHD) u/s d/s Yarrawonga 124.90 -0.10 - No. 7 22.10 -0.05 +1.69 No. 26 Torrumbarry 86.05 -0.00 - No. 6 Murtho 19.25 +0.01 +0.31 No. 15 Euston 47.60 +0.04 - No. 5 Renmark 16.30 +0.02 +0.27 No. 11 Mildura 34.40 +0.03 +0.31 No. 4 Bookpurnong 13.20 -0.06 +1.01 No. 10 Wentworth 30.80 +0.06 +0.47 No. 3 Overland Corner 9.80 +0.00 +0.36 No. 9 Kulnine 27.40 +0.04 +0.15 No. 2 Waikerie 6.10 -0.01 +0.34 No. 8 Wangumma 24.60 -0.01 +0.30 No. 1 Blanchetown 3.20 +0.03 +0.25

Lower Lakes FSL = 0.75 m AHD Lake Alexandrina average level for the past 5 days (m AHD) 0.83

Barrages Fishways at Barrages Openings Level (m AHD) No. Open Rock Ramp Vertical Slot 1 Vertical Slot 2 Dual Vertical Slots Goolwa 128 openings 0.84 2 - Open Open - Mundoo 26 openings 0.80 All closed - - - Open Hunters Creek - - - - Open - - Boundary Creek 6 openings - 1 - Open - - Ewe Island 111 gates - All closed - - - Open Tauwitchere 322 gates 0.83 2 Open Open Open - AHD = Level relative to Australian Height Datum, i.e. height above sea level

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Week ending Wednesday 23 Dec 2020

State Allocations (as at 23 Dec 2020) NSW ‐ Murray Valley Victorian ‐ Murray Valley High security 97% High reliability 88% General security 43% Low reliability 0%

NSW – Murrumbidgee Valley Victorian ‐ Goulburn Valley High security 95% High reliability 100% General security 77% Low reliability 0%

NSW ‐ Lower Darling South Australia – Murray Valley High security 100% High security 100%

General security 30%

NSW : https://www.industry.nsw.gov.au/water/allocations‐availability/allocations/summary

VIC : http://nvrm.net.au/seasonal‐determinations/current

SA : https://www.environment.sa.gov.au/topics/river‐murray/water‐allocations‐and‐announcements

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