River Murray Weekly Report For the week ending Wednesday, 31 March 2020

Trim Ref: D21/8708 Rainfall and inflows Following last week’s widespread heavy falls, this week’s rainfall was mostly confined to the southern Basin, particularly the upper Murray and upper Murrumbidgee catchments (Map 1). Dry and warmer conditions are forecast across most of the Basin during the Easter period.

Map 1: Murray-Darling Basin rainfall for the week ending 31 March 2021. Source: Bureau of Meteorology. Modest and short-lived streamflow responses were observed across upper Murray tributaries after last week’s rain. Streamflows have gradually decreased as dry conditions returned, with further recession likely over the coming week. 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.

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River operations

• Significant flows in the northern Basin • River users and houseboat owners should be aware that the river level will vary between and Wentworth Weirs over the coming weeks • Lake Mulwala and weir pools at Torrumbarry, Euston, Mildura, and Wentworth to remain at normal levels over Easter period • Red alert levels continue for blue-green algae at Wentworth and Buronga

Easter Flows With the arrival of the busy Easter and school holiday period, river users are reminded that River Murray levels from to South depend on a range of factors including weather and system demands.

Following widespread rainfall last week, there was a substantial reduction in irrigation demand and river losses. This increased flows in some parts of the River Murray System. To compensate for irrigation reductions and to conserve water in the upper Murray storages, releases from Hume, Yarrawonga Weir and Stevens Weir were reduced. So, while some parts of the river observed higher flows following the rain, others had lower flows. This week’s warmer and drier conditions have resulted in some demands, and therefore Hume releases, increasing in recent days.

In short, depending on the location along the system, flows may be falling, steady or rising during the Easter and school holiday period. River users can monitor River Murray levels and flow forecasts at key locations on the MDBA’s River Murray data webpage to assist in planning any river activities.

Recreational activities that require deeper water such as boating can take advantage of many weir pools along the river which will remain near normal levels over the Easter period. Water demand The MDBA has been actively monitoring shortfall risks over the irrigation season. 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 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 Wakool Junction and the SA border over the coming week is negligible. The MDBA is continuing to monitor weather conditions and forecast demands and will continue to actively manage the risk of delivery shortfall across the high demand summer-autumn period as conditions evolve. The risk of a system shortfall has abated with the recent rainfall and irrigation demand reduction. The MDBA will continue to monitor conditions and operate the Murray in consultation with the states. 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 The Murray and Lower Darling Regional Algal Coordinating Committee has continued to declare a number of red and amber alerts for blue-green algae in the River Murray System. Currently, a red alert warning continues on the River Murray at Buronga and Wentworth. Amber alerts are in place at a number of sites on the River Murray and along the Edward- system. The locations of these sites are available on the WaterNSW website. 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.

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River operations Total active storage increased by 30 GL over the last week to 3,916 GL (46% capacity). At Dartmouth Reservoir, the storage increased by 6 GL to 2,454 GL (64% capacity). The flow at Colemans targeted around 250 ML/day to help maintain the flow at Tallandoon near 600 ML/day. Over the past week the Hume Reservoir storage increased by 23 GL to 1,463 GL (49% capacity). The Hume release gradually increased from 4,400 ML/day to 8,000 ML/day this week, and a slight reduction is forecast in coming days.

Photo 1: Wymah Ferry crossing on the Murray arm of Hume Dam. Photo: Mathew Todhunter, MDBA.

The Lake Mulwala level is currently near 124.8 m AHD, well within the normal operating range (124.6 to 124.9 m AHD) and similar levels are expected over the coming days, providing opportunities for recreational activities over the Easter period. With drier and warmer weather forecast over the coming week, irrigation demands have started to increase. Diversion to Mulwala Canal has gradually risen from a low of 600 ML/day to 1,000 ML/day and further increase is expected over coming days. On the Victorian side, diversion to Yarrawonga Main Channel remains low near 300 ML/day and is also anticipated to increase in coming days. The release from Yarrawonga Weir gradually reduced to 7,000 ML/day this week and is likely to remain near this rate over the coming week at least.

The gates of the Offtake have been lifted clear of the water, meaning flows have varied in-line with upstream Murray levels. This week flow through the offtake eased from around 1,600 ML/day to near 1,400 ML/day as Murray levels gradually lessened, and some further reduction is expected in coming days. Flow through Gulpa Creek Offtake has averaged around 250 ML/day this week. Downstream on the Edward River, the release from Edward Escape has reduced from 800 ML/day to near 100 ML/day as MDBA reduces system transfers following last week’s rain, and will increase in coming days to help meet Edward-Wakool demands, including diversion to Wakool Main Canal which has increased from 350 to 800 ML/day. The flow downstream of Stevens Weir has reduced from around 2,500 ML/day in mid-March down to the current rate around 600 ML/day, and similar flows are expected over the coming week. Flow through the Wakool River and Yallakool Creek offtakes averaged near 50 and 220 ML/day, respectively, with higher flows expected over the coming weeks as part of an autumn environmental pulse to support native fish. Flow through the Colligen Creek offtake has averaged near 200 ML/day this week. On the , the flow measured at McCoys Bridge eased from 1,350 ML/day towards 1,000 ML/day as delivery of Inter Valley Trade (IVT) reduced. Flows are anticipated to average around 950 ML/day over the coming

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week. Water for the environment will be used in the Goulburn River in April with a planned pulse of up to 7,000 ML/day late in the month. In addition to the Goulburn River, the delivery of water from the Goulburn IVT account to the Murray has continued from the and Broken Creek with a combined IVT delivery of around 40 GL in March. For more information see the Goulburn-Murray Water website. Up to 40 GL has been ordered from the Goulburn system for April but may not be required if further rainfall occurs in coming weeks. Information regarding opportunities for allocation trade between the Goulburn and Murray Valleys is available at the Victorian water register website. Diversions to National Channel reduced to around 1,400 ML/day and will increase in coming days as conditions warm and demands increase. The release from Torrumbarry Weir has decreased to around 5,000 ML/day and will reduce over coming days as both upstream Murray and Goulburn flows ease and irrigation demands increase. River users and houseboat owners should be aware that the river level will vary between Barmah and Wentworth Weir over the coming weeks. Inflow from the , measured at Balranald, reduced from around 2,000 to 1,100 ML/day, before increasing to 1,400 ML/day late in the week. Flows are expected to increase further over the coming week as up to 45 GL of IVT is delivered from the Murrumbidgee system in April. The Murrumbidgee IVT balance is open for trade from the Murray to the Murrumbidgee (96.1 GL), but remains closed for trade from the Murrumbidgee to the Murray.

Photo 1: Releases from Scrivener Dam remain elevated following last week’s heavy rain. After flowing along the lower , this water enters the upper Murrumbidgee River before flowing into Burrinjuck Dam. Photo courtesy of Kate Sandles, MDBA.

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At Euston Weir, the weir pool level remains near full supply level (FSL). The downstream release peaked at 9,300 ML/day during this week and is forecast to slowly reduce over the coming week. Several of the upstream tributaries of the Barwon-Darling have experienced flooding following last week’s heavy rain, including Major flooding in the MacIntyre, Dumaresq and . The BoM has issued numerous current major, moderate and minor flood warnings for tributaries. Please see the BoM website for more information. Significant river rises are now being observed in the with the flow at Walgett now near 29,000 ML/day and rising. For updates on flow forecasting in the northern Basin please see the WaterNSW website. It will take several weeks to accurately forecast inflows from the northern Basin into the Barwon-Darling River and into the Menindee Lakes. This is due to large uncertainties caused by variable losses, flow attenuation and travel times, and water absorbed by wetlands and floodplains such as the Gwydir Wetlands and the Macquarie Marshes. MDBA will continue to provide updates on flows into the Darling River over the coming weeks. Menindee Lakes total storage remained steady at 300 GL (17% capacity) this week. The release from Weir 32 continues at around 350 ML/day. At Wentworth Weir, the weir pool level continues to be managed around FSL. The downstream flow increased during the week to the current rate near 7,400 ML/day and is forecast to gradually rise over coming days.

Downstream at Lock 9 the weir pool continues to vary near FSL. The Lock 8 and Lock 7 weir pools are currently at around 40 cm below FSL. During April, the Lock 7 weir pool will gradually be increased to around 55 cm above FSL to facilitate increased flows into Lindsay River that enable pumping into Lake Wallawalla during May and June for environmental outcomes. The storage level at Lake increased by 2 GL to 193 GL (29% capacity) this week. During April and May, the storage will increase as water from upstream is captured to reach the end of May target of 350 GL. The flow to averaged 5,800 ML/day for the week and is forecast to decrease to around 5,400 ML/day over the coming days. The flow includes South Australia’s normal monthly Entitlement flow, small volumes of consumptive trade and water for the environment. The Lower Lakes 5-day average water level is 0.62 m AHD. 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 KREMOR A/g Executive Director, River Management

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Water in Storage Week ending Wednesday 31 Mar 2021 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 3 856 461.64 2 454 64% 71 2 383 +6 Hume Reservoir 192.00 3 005 182.67 1 463 49% 23 1 440 +23 Lake Victoria 27.00 677 22.42 193 29% 100 93 +2 Menindee Lakes 1 731* 300 17% (- -) # 0 +0 Total 9 269 4 410 48% - - 3 916 +30 Total Active MDBA Storage 46% ^

Major State Storages Burrinjuck Reservoir 1 026 885 86% 3 882 +155 Blowering Reservoir 1 631 1 245 76% 24 1 221 +11 Eildon Reservoir 3 334 2 018 61% 100 1 918 -5 * 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 30 Mar 2021 Storage Active Storage (GL) Weekly Change (GL) Diversion (GL) This Week From 1 May 2020 Lake Eucumbene - Total 1 007 -16 Snowy-Murray +34 815 Snowy-Murray Component - n/a Tooma-Tumut +5 242 Target Storage 1 410 Net Diversion 32 572 Murray 1 Release +38 1 103 Major Diversions from Murray and Lower Darling (GL) * This Week From 1 July 2020 Victoria This Week From 1 July 2020 Murray Irrig. Ltd (Net) 24.7 540 Yarrawonga Main Channel (net) 4 168 Wakool Sys Allowance 2 92 Torrumbarry System + Nyah (net) 7 259 Western Murray Irrigation 0.7 22 Sunraysia Pumped Districts 2.1 98 Licensed Pumps 5 212 Licensed pumps - GMW (Nyah+u/s) 1 20 Lower Darling n/a 2 Licensed pumps - LMW 10 387 TOTAL 32.4 868 TOTAL 24.1 932 * 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 186.0 * * Flow to SA will be greater than normal entitlement for Flow this week 40.7 (5 800 ML/day) this month due to environmental flows. Flow so far this month 196.2

Flow last month 238.2 Salinity (EC) (microSiemens/cm at 25o C) Current Average over the last week Average since 1 August 2020 Swan Hill 70 70 90 Euston - - - Red Cliffs 110 110 130 Merbein 110 110 130 Burtundy (Darling) 490 490 390 Lock 9 110 120 130 Lake Victoria 130 130 120 Berri 140 150 160 Waikerie 220 220 200 Morgan 230 220 210 Mannum 260 260 230 Murray Bridge 270 270 250 Milang (Lake Alex.) 720 720 750 Poltalloch (Lake Alex.) 620 650 1 090 Meningie (Lake Alb.) 1 720 1 690 1 630 Goolwa Barrages 1 360 1 330 1 220

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River Levels and Flows Week ending Wednesday 31 Mar 2021 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) Khancoban - - - 4 970 F 6 510 6 470 Jingellic 4.0 1.98 208.50 7 000 F 9 040 7 780 Tallandoon ( ) 4.2 1.41 218.30 600 F 660 700 Heywoods 5.5 2.78 156.41 7 910 R 5 550 7 420 Doctors Point 5.5 2.61 151.08 9 460 R 7 390 8 610 4.3 1.66 149.10 - - - - Corowa 4.6 1.84 127.86 7 410 R 6 620 10 150 Yarrawonga Weir (d/s) 6.4 1.18 116.22 6 940 R 7 040 8 160 Tocumwal 6.4 1.71 105.55 6 760 S 7 340 8 290 Torrumbarry Weir (d/s) 7.3 1.86 80.41 5 040 F 5 930 5 950 Swan Hill 4.5 1.21 64.13 5 990 F 6 290 5 340 Wakool Junction 8.8 3.03 52.15 8 240 F 8 330 6 830 Euston Weir (d/s) 9.1 1.66 43.50 9 260 F 9 070 7 880 Mildura Weir (d/s) - - 8 450 F 7 760 6 820 Wentworth Weir (d/s) 7.3 2.89 27.65 7 380 R 6 900 6 100 Rufus Junction - 3.28 20.21 5 430 R 5 390 6 440 Blanchetown (Lock 1 d/s) - 0.63 - 4 080 F 4 140 4 000

Tributaries Kiewa at Bandiana 2.8 1.26 154.49 830 F 990 440 Ovens at Wangaratta 11.9 8.14 145.82 920 F 1 090 500 Goulburn at McCoys Bridge 9.0 1.53 92.95 1 060 F 1 210 1 400 Edward at Stevens Weir (d/s) 5.5 0.83 80.60 530 F 910 1 950 Edward at Liewah - 2.62 58.00 2 010 F 2 110 2 020 Wakool at Stoney Crossing - 1.41 54.90 460 F 490 410 Murrumbidgee at Balranald 5.0 1.83 57.79 1 410 R 1 410 1 990 Barwon at Mungindi 6.1 5.93 - 7 190 F 7 850 1 950 Darling at Bourke 9.0 4.87 - 6 400 R 4 570 1 950 Darling at Burtundy Rocks - 0.77 - 240 R 240 220

Natural Inflow to Hume 3210 750 (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 -0.11 - No. 7 22.10 -0.36 +0.97 No. 26 Torrumbarry 86.05 +0.00 - No. 6 Murtho 19.25 +0.05 +0.05 No. 15 Euston 47.60 +0.00 - No. 5 Renmark 16.30 +0.03 +0.13 No. 11 Mildura 34.40 +0.02 +0.18 No. 4 Bookpurnong 13.20 +0.04 +0.49 No. 10 Wentworth 30.80 +0.04 +0.25 No. 3 Overland Corner 9.80 +0.04 +0.22 No. 9 Kulnine 27.40 -0.06 -0.35 No. 2 Waikerie 6.10 +0.06 +0.17 No. 8 Wangumma 24.60 -0.38 -0.22 No. 1 Blanchetown 3.20 +0.07 -0.12

Lower Lakes FSL = 0.75 m AHD Lake Alexandrina average level for the past 5 days (m AHD) 0.62

Barrages Fishways at Barrages Openings Level (m AHD) No. Open Rock Ramp Vertical Slot 1 Vertical Slot 2 Dual Vertical Slots Goolwa 128 openings 0.65 1 - Open Open - Mundoo 26 openings 0.60 All closed - - - Open Hunters Creek - - - - Open - - Boundary Creek 6 openings - 1 - Open - - Ewe Island 111 gates - All closed - - - Open Tauwitchere 322 gates 0.63 5 Open Open Open - AHD = Level relative to Australian Height Datum, i.e. height above sea level

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Week ending Wednesday 31 Mar 2021

State Allocations (as at 1 April 2021) NSW - Murray Valley Victorian - Murray Valley High security 97% High reliability 100%

General security 50% Low reliability 0%

NSW – Murrumbidgee Valley Victorian - High security 100% High reliability 100%

General security 100% 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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