River Murray Weekly ReportFor the week ending Wednesday, 21 October 2020

Trim Ref: D20/43866

Rainfall and inflowsModerate rain fell across much of the southern Murray-Darling Basin this week, with the highest totals in the Victorian and New South Wales ranges (Map 1). In Victoria, Mt Hotham and Falls Creek received totals of 116 and 109 mm respectively. In New South Wales, Cabramurra AWS in the Snowy Mountains received a total of 44 mm and Wagga Wagga in the Riverina region received a total of 32 mm. In the northern Basin, Stanthorpe in the East Darling Downs of Queensland recorded 16 mm while 12 mm fell at Hungerford, in the Paroo River catchment.

Map 1 - Murray-Darling Basin rainfall totals for week ending 21 October 2020 (Source: Bureau of Meteorology)

This week’s rainfall produced good stream flow responses in the upper Murray, Mitta Mitta, Kiewa and Ovens Rivers. The upper Mitta Mitta River at Hinnomunjie Bridge peaked at 6,900 ML/day. On the Kiewa River, the flow at Bandiana peaked at around 4,900 ML/day with the river rising above the Minor Flood level. On the Ovens River, the flow at Peechelba reached 13,700 ML/day before receding. 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 Murray River Basin Daily River Report at the WaterNSW website.

Given the Bureau of Meteorology’s (BoM) current 8 day rainfall forecast, renewed streamflow increases are likely in the coming week. For information on any current and potential flood warnings that may develop, please refer to the Bureau of Meteorology website.

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River operations

Water availabilityRainfall over the past few months has improved system inflows (see graph on last page of this report) and water availability. The most recent allocation announcements saw New South Wales Murray General Security increase by 9 percentage points to 26% , while Victorian Murray High reliability improved from 40% to 55%. A summary of current allocations are available at the end of this report.

Water quality impactsAmber alerts for blue-green algae remain current in the River Murray system for the Gulpa Creek at Mathoura, the Edward River at Old Morago, River Murray at Buronga and River Murray at Lock 8. An Amber alert is now also in place at Tooleybuc on the Murray. 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 Ni ñ a 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 New South Wales. After three hot and dry years, floodplains have a high load of leaf litter and other organic material. La Niña conditions in spring increase the risk of heavy rain and flooding, which can wash organic matter into waterways and lead to hypoxic blackwater events. More information is provided in a MDBA and WaterNSW joint media release.

Monthly snapshot of water in the systemRiver 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 operationsOver the past week, MDBA total active storage increased by 109 GL to 4,976 GL (61% capacity).

At Dartmouth Reservoir, the storage level increased by 34 GL to 2,275 GL (59% capacity). The release, measured at Colemans, continued to target the minimum flow rate of 200 ML/day.

At Hume Reservoir the storage level increased by 88 GL to 2,272 GL (76% capacity). Releases from Hume have fluctuated between the minimum release of 600 ML/day and 4,500 ML/day in response to downstream tributary inflows which have varied with rainfall. Currently, the Hume release above 600 ML/day is water for the environment, released to help meet a target flow rate downstream at Yarrawonga Weir. The current Hume release of 3,200 ML/day is expected to be reduced further in coming days given the current rainfall forecast.

At Lake Mulwala, the pool level is 124.69 m AHD and within the normal operating range of between 124.6 and 124.9 m AHD. Diversion at the major irrigation off-takes reduced this week in response to rainfall. Diversion to Mulwala Canal is currently 1,500 ML/day and on the Victorian side, about 300 ML/day is being diverted into Yarrawonga Main Channel. With rainfall forecast, diversions are expected to remain suppressed over the coming days.

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NSW Murray general security allocations and Victorian Murray high reliability water shares increase Further rainfall forecast Hume dam releases vary to meet Yarrawonga environmental target flow Water for the environment supporting Murray Cod outcomes in the Murray and Lower Darling

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Over the past week tributary inflows from the Ovens River (Wangaratta peaked at 19,400 ML/day) and Kiewa River (Bandiana reached 4,900 ML/day and remains at Minor Flood level) has boosted the Yarrawonga Weir release briefly to 16,000 ML/day. As tributary inflows eased and the natural ‘fresh’ or flow pulse downstream of Yarrawonga Weir receded, water for the environment released from Hume maintained Yarrawonga releases near 15,000 ML/day. This target, on behalf of environmental water holders, will continue over coming weeks to provide water levels that support the Murray Cod nesting season, while also increasing lateral connectivity between the River Murray and the Barmah—Millewa Forest. This greater connectivity has been enabled by the opening of selected regulators in the forest. This helps promote increased productivity in the river and supports plants and animals in the forest. The increased flows have also triggered a response from native fish, with significantly more fish observed moving through fishways including at the Yarrawonga Weir fish elevator (Photo 1). All actions associated with water for the environment are tracked and water usage debited from environmental water holder accounts.

Photo 1 – The recent higher flows downstream of Yarrawonga, in-part met from water for the environment, have triggered increased native fish movement. Pictured is the fish elevator at Yarrawonga Weir. Fish travelling upstream enter the cage and are carefully transported to the upstream side of the weir by Yarrawonga Weir staff to enable upstream fish movement. The elevator also includes a method for capturing and removing carp, an invasive pest species, also seen in this image. Photo courtesy Luke Cruikshank, Goulburn-Murray Water.

Should rainfall produce significant stream flows in the Ovens and Kiewa Rivers, the flow downstream of Yarrawonga may return above 15,000 ML/day. 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.

This week flow through the Edward River Offtake averaged around 1,570 ML/day, while flow through the Gulpa Creek Offtake was increased to around 700 ML/day to help fill wetlands adjacent to the creek. As additional water

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moves through Millewa forest and into the Edward River, and as rain reduced irrigation demand, the release from Stevens Weir increased from 1,000 to 1,700 ML/day and a further increase is expected over the coming week.

On the Goulburn River, the flow measured at McCoys Bridge gradually reduced this week from 9,500 ML/day and is currently near 5,600 ML/day. A portion of this flow is comprised of water for the environment while the remainder is mostly from recent rainfall and will be used to meet downstream demands along the Murray or be re-regulated in Lake Victoria. Information regarding opportunities for allocation trade between the Goulburn and Murray Valleys is available at the Victorian water register website .

Diversions to National Channel from the Torrumbarry Weir pool remained steady at around 1,450 ML/day. A portion of this flow is being used to maintain baseflows in the Gunbower Creek with the aim of providing increased habitat for native fish and other aquatic animals over the spring period. Flow in Gunbower Creek returns to the River Murray via Koondrook Spillway, downstream of Torrumbarry Weir near Barham. This week the release downstream of Torrumbarry Weir averaged around 12,500 ML/day.

Photo 2 – Reedy Lagoon in Gunbower Forest benefitting from the recent delivery of water for the environment. Photo courtesy Will Honybun, NCCMA.

Inflow from the Murrumbidgee River, measured at Balranald , averaged around 1,350 ML/day. The Murrumbidgee IVT balance is open for trade from the Murray to the Murrumbidgee (102 GL) but remains closed for trade from the Murrumbidgee to the Murray.

At Euston Weir, the weir pool level is at FSL. The downstream release increased from 8,600 to 13,200 ML/day and some further increase is expected in coming days.

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Photo 3 – Water flowing along Mullaroo Creek. Photo courtesy David Wood, Mallee Catchment Authority.

Menindee Lakes storage eased this week to around 458 GL (26.5% capacity). The downstream release, measured at Weir 32, remains near 400 ML/day, with small releases of water for the environment continuing to help boost the rate above the normal minimum target. These flows aim to improve the condition of the lower Darling and help Murray Cod breed this spring. For more information refer to the Commonwealth Environmental Water Office and NSW Department of Planning, Industry and Environment. Some water restrictions remain current in NSW. Links to drought services and assistance can be accessed via the MDBA drought webpage .

At Wentworth Weir, the weir pool level is being managed at around FSL. The downstream flow averaged around 7,700 ML/day and will rise 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 fell this week by 13 GL to 623 GL (92% capacity) as releases were made to deliver the required flow to South Australia. The volume stored in Lake Victoria is forecast to continue falling away over the coming week before rising again as recent inflows from tributaries downstream of Hume arrive and are captured, contributing to improved water availability for all water entitlement holders.

At this stage it is forecast that all flows arriving at Lake Victoria in excess of South Australian requirements can be captured and re-regulated into Lake Victoria. However, if upcoming rain reduces system demands and losses, whilst further boosting tributary inflows, the potential for a renewed period of unregulated (surplus) flow in the Murray will increase. The MDBA continues to monitor system flows and demand conditions closely and will advise of a new unregulated event if one eventuates during the coming weeks. We encourage irrigators to stay in touch with their water resource manager for any updates on the potential availability of access to supplementary water licences.

The flow to South Australia averaged around 9,500 ML/day and includes the October South Australian monthly Entitlement plus water for the environment and traded volumes. Over the coming days the flow is expected to increase to around 12,000 ML/day.

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The Lower Lakes 5-day average water level is 0.86 m AHD. Unregulated flows and delivery of water for the environment into the Lower Lakes over the past few months have allowed on-going releases through the barrages to target outcomes in the Coorong and at the Murray Mouth. Increased barrage releases will continue to be made when conditions allow to push fresh water into the Coorong. 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 REYNOLDSExecutive Director, River Management

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Water in Storage Week ending Wednesday 21 Oct 2020

MDBA StoragesFull

Supply Level

Full Supply Volume

Current Storage Level

Current Storage Dead

StorageActive

Storage

Change in Total Storage for the

Week  (m AHD) (GL) (m AHD) (GL) % (GL) (GL) (GL)

Dartmouth Reservoir 486.00 3 856 457.96 2 275 59% 71 2 204 +34Hume Reservoir 192.00 3 005 188.05 2 272 76% 23 2 249 +88Lake Victoria 27.00 677 26.55 623 92% 100 523 -13Menindee Lakes   1 731*   459 27% (- -) # 0 -7Total   9 269   5 629 61% - - 4 976 +103Total Active MDBA Storage             59% ^  

                 

Major State StoragesBurrinjuck Reservoir   1 026   816 79% 3 813 -2Blowering Reservoir   1 631   1 345 82% 24 1 321 +2Eildon Reservoir   3 334   2 198 66% 100 2 098 +61

* 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 20 Oct 2020

Storage Active Storage (GL) Weekly Change (GL) Diversion (GL) This Week From 1 May 2020

Lake Eucumbene - Total 1 332 +40 Snowy-Murray +17 438Snowy-Murray Component 621 +14 Tooma-Tumut +14 172Target Storage 1 400   Net Diversion 3 267

     Murray 1 Release +28 640

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) 15.4 177 Yarrawonga Main Channel (net) 3 35Wakool Sys Allowance 1.3 31 Torrumbarry System + Nyah (net) 7.1 71Western Murray Irrigation 0.3 2 Sunraysia Pumped Districts 1.4 13

Licensed Pumps 3.2 52Licensed pumps - GMW (Nyah+u/s) 0.8 3

Lower Darling 0.0 0 Licensed pumps - LMW 7 57TOTAL 20.2 262 TOTAL 19.3 179

* 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)* Flow to SA will be greater than normal entitlement for this month due to environmental flows.

Entitlement this month 170.0 *  Flow this week 62.1 (8 900 ML/day)Flow so far this month 200.6Flow last month 274.0

Salinity (EC) (microSiemens/cm at 25o C)

  Current Average over the last week Average since 1 August 2020

Swan Hill 110 100 120Euston - - -Red Cliffs 160 150 140Merbein 170 150 170Burtundy (Darling) 390 400 320Lock 9 150 160 140Lake Victoria 130 130 120Berri 180 170 150Waikerie 220 210 200Morgan 220 220 200Mannum 210 210 220

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Murray Bridge 220 230 240Milang (Lake Alex.) 810 800 850Poltalloch (Lake Alex.) 480 450 470Meningie (Lake Alb.) 1 580 1 580 1 670Goolwa Barrages 900 900 1 380

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River Levels and Flows Week ending Wednesday 21 Oct 2020

 Minor Flood

Stage Gauge Height Flow Trend Average Flow this Week

Average Flow last Week

River Murray (m)local (m)

(m AHD) (ML/day)   (ML/day) (ML/day)

Khancoban - - - 6 990 R 6 180 5 470Jingellic 4.0 2.60 209.12 12 860 F 13 290 14 250Tallandoon ( Mitta Mitta River ) 4.2 1.78 218.67 1 490 F 1 620 1 850Heywoods 5.5 1.99 155.62 3 300 F 3 400 1 130Doctors Point 5.5 2.38 150.85 7 950 F 7 500 4 660Albury 4.3 1.39 148.83 - - - -Corowa 4.6 1.91 127.93 7 810 R 6 170 4 580Yarrawonga Weir (d/s) 6.4 2.18 117.22 14 420 F 14 840 9 690Tocumwal 6.4 2.84 106.68 15 020 F 14 110 8 690Torrumbarry Weir (d/s) 7.3 3.54 82.08 11 470 F 12 650 9 650Swan Hill 4.5 2.38 65.30 13 760 S 12 350 7 480Wakool Junction 8.8 4.15 53.27 13 680 R 11 920 7 770Euston Weir (d/s) 9.1 2.25 44.09 13 230 R 11 160 7 880Mildura Weir (d/s)   - - 11 270 F 8 510 7 190Wentworth Weir (d/s) 7.3 3.15 27.91 10 870 R 7 900 6 990Rufus Junction - 3.90 20.83 9 260 R 7 920 8 060Blanchetown (Lock 1 d/s) - 0.91 - 6 550 F 6 560 9 140               Tributaries              Kiewa at Bandiana 2.8 2.89 156.12 4 850 R 3 840 3 800Ovens at Wangaratta 11.9 10.99 148.67 11 440 F 10 510 12 220Goulburn at McCoys Bridge 9.0 3.83 95.25 5 640 R 6 870 7 000Edward at Stevens Weir (d/s) 5.5 1.72 81.50 1 590 S 1 420 740Edward at Liewah - 1.63 57.01 970 F 1 060 1 190Wakool at Stoney Crossing - 1.44 54.93 510 R 460 410Murrumbidgee at Balranald 5.0 1.78 57.74 1 350 R 1 350 1 070Barwon at Mungindi 6.1 3.09 - 60 F 70 90Darling at Bourke 9.0 4.04 - 240 F 240 250Darling at Burtundy Rocks - 0.77 - 250 R 240 250               Natural Inflow to Hume           20 440 26 240

(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 -0.21 - No. 7 Rufus River 22.10+0.1

6 +1.59No. 26 Torrumbarry 86.05

+0.00 - No. 6 Murtho 19.25

+0.10 +0.38

No. 15 Euston 47.60 -0.01 - No. 5 Renmark 16.30+0.1

9 +0.51

No. 11 Mildura 34.40+0.0

1 +0.34 No. 4 Bookpurnong 13.20+0.3

0 +0.91

No. 10 Wentworth 30.80+0.0

2 +0.51 No. 3 Overland Corner 9.80+0.0

3 +0.47

No. 9 Kulnine 27.40+0.0

5 +0.27 No. 2 Waikerie 6.10+0.2

1 +0.36

No. 8 Wangumma 24.60+0.1

0 +0.46 No. 1 Blanchetown 3.20+0.1

5 +0.16

Lower Lakes FSL = 0.75 m AHDLake Alexandrina average level for the past 5 days (m AHD) 0.86

Barrages Fishways at Barrages

  Openings Level (m AHD)No. Open Rock Ramp Vertical Slot 1

Vertical Slot 2 Dual Vertical Slots

Goolwa 128 openings 0.86 4 - Open Open -

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Mundoo 26 openings 0.83All

closed - - - OpenHunters Creek - - - - Open - -Boundary Creek 6 openings - 1 - Open - -

Ewe Island 111 gates -All

closed - - - OpenTauwitchere 322 gates 0.85 12 Open Closed Open -

AHD = Level relative to Australian Height Datum, i.e. height above sea level

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Week ending Wednesday 21 Oct 2020

State Allocations (as at 21 Oct 2020)NSW - Murray Valley Victorian - Murray Valley

High security 97%General security 26%

High reliability 55%Low reliability 0%

NSW – Murrumbidgee Valley Victorian - Goulburn ValleyHigh security 95%General security 54%

High reliability 77%Low reliability 0%

NSW - Lower Darling South Australia – Murray ValleyHigh security 100%General security 30%

High security 100%

NSW : https://www.industry.nsw.gov.au/water/allocations-availability/allocations/summaryVIC : http://nvrm.net.au/seasonal-determinations/currentSA : https://www.environment.sa.gov.au/topics/river-murray/water-allocations-and-announcements

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