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River Murray Weekly Report For the week ending Wednesday, 22 July 2020

Trim Ref: D20/25074

Rainfall and inflows Conditions were mostly dry across the Murray-Darling Basin this week, with rainfall limited to the southern slopes and ranges (Map 1). The Bureau of Meteorology (BoM) is currently forecasting a small amount of rainfall over the southern Murray-Darling Basin in the coming 8 days.

Map 1 - Murray-Darling Basin rainfall totals for week ending 22 July 2020 (Source: Bureau of Meteorology)

Stream flows in the upper and mid-Murray tributaries receded this 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 Murray River Basin Daily River Report at the WaterNSW website

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River operations

Unregulated flow event Tributary inflows downstream of Hume Dam have resulted in continued elevated flows through the mid and lower Murray. Lake Victoria is at 93% capacity and the MDBA is actively slowing the rate of fill of the lake in accordance with the requirements of the Lake Victoria Operating Strategy. There is sufficient surplus flow remaining to extend the period of unregulated flow that commenced on 27 June. For more information on the expected duration and the river reaches where unregulated flow currently applies, refer to supplementary announcements from WaterNSW.

River operations and the COVID-19 virus The MDBA is continuing to work with government partners and stakeholders during this challenging time. In response to the impact of COVID-19, the MDBA has enacted business continuity arrangements to ensure the continued operation of our business functions. River operations have been identified as a priority in this time as running the river is essential to supporting irrigation supply to agricultural industries.

We hope all our community members remain safe at this time. We encourage all river users to evaluate plans against government advice, social distancing and travel, and to support actions to limit the spread of COVID-19.

Water quality impacts An amber alert for blue-green algae remains current in the River Murray system at Buronga. 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.

Operations Over the past week, MDBA total active storage (Dartmouth, Hume and Lake Victoria) increased by 88 GL to 3,881 GL (46% capacity).

At Dartmouth Reservoir, the storage increased by 12 GL to 2,044 GL (53% capacity). During the week the power station operator (AGL) continued to release entitlement water from Dartmouth for the purposes of electricity generation. The release rate targeted around 1,000 to 1,200 ML/day (measured at Colemans) for much of the week, compared with normal minimum releases for this time of year of 200 ML/day.

At Hume Reservoir, the storage increased by 76 GL to 1,401 GL (47% capacity). This includes around 37 GL released from Snowy Hydro’s Khancoban Pondage into the Murray River upstream of Bringenbrong. Hume storage is expected to rise in the coming weeks as unregulated tributary inflows and releases from Snowy Hydro continue. The release from Hume remains at the minimum flow rate of 600 ML/day as elevated inflows from the Kiewa and Ovens Rivers meet and exceed minimum flow requirements downstream at Yarrawonga.

At Lake Mulwala, the diversion to Mulwala Canal reached around 3,000 ML/day as Murray Irrigation Limited (MIL) continued to refill their irrigation channels and make available supplementary access water to customers. Goulburn-Murray Water also commenced diverting small volumes to the Yarrawonga Main Canal in preparation for refilling their irrigation channels. In response to the increase in diversions and receding tributary inflows, the release downstream of Yarrawonga Weir was gradually reduced from 10,500 ML/day to 7,400 ML/day. The release is expected to continue to reduce over the coming week to below 6,000 ML/day.

Downstream in the Barmah - Millewa Forest, a number of regulators remained open to manage river levels through the Choke within the capacity of the river channel (ie a water level below 2.6 m on the local gauge at Picnic Point). However, with the release downstream of Yarrawonga reducing below 9,000 ML/day over the weekend, the forest regulators will be closed in the coming days (Note: a release of about 9,000 ML/day from Yarrawonga Weir is a

• Storage in Dartmouth and Hume continues to rise. • Tributary inflows downstream of Hume extend period of unregulated flow, • Unregulated flow at the lower Lakes boosts release to the Coorong.

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proxy for the capacity of the river through the Choke when around 2,000 ML/day is diverted via the Edward-Wakool system, forest regulators are closed and there are low diversions for irrigation in the reach between Yarrawonga and Barmah).

Photo 1: Kiewa River East Branch (Photo Courtesy Hugo Bowman)

On the Edward River, return flows from the Murray via the Millewa Forest increased by around 200 ML/day late in the week. These return flows are expected to continue for another few days before reducing and finally ceasing in around two weeks following the closure of the forest regulators in the coming days. Diversions into the Wakool River, Yallakool and Colligen Creeks remain at levels sufficient to provide entitlement holders with access to unregulated flows. At Stevens Weir, diversions to the Wakool Main Canal were around 1,100 ML/day and the release downstream of the weir averaged 550 ML/day.

On the Goulburn River, the flow measured at McCoys Bridge peaked near 9,000 ML/day early in the week before reducing to the current rate of 4,000 ML/day. Inflows from the Goulburn to the Murray are forecast to remain around 3,000 to 5,000 ML/day over the coming week. Allocation trade from the Goulburn to the Murray system is currently closed. Information regarding opportunities for allocation trade between the Goulburn and Murray Valleys is available at the Victorian water register website.

The level of the Torrumbarry Weir pool continues to vary daily within the target range of 20-30 cm below Full Supply Level (FSL) as part of the weir pool variability program. Varying pool levels helps to reduce the incidence of notching and can help improve bank stability for riverbanks within the influence of the weir pool. Diversions to National Channel from the weir pool were steady at around 420 ML/day to maintain winter baseflows in the Gunbower Creek for the benefit of native fish. Around 200 ML/day of this flow returns to the River Murray downstream of Torrumbarry Weir near Barham Bridge, via Koondrook Spillway The additional loss arising from this watering action is debited against environmental water holders’ entitlements. In response to inflows from the

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Goulburn River, the downstream release from Torrumbarry Weir peaked during the week at 14,500 ML/day and is forecast to continue to steadily reduce over the coming week.

Inflow from the Murrumbidgee River, measured at Balranald, gradually receded from 2,400 ML/day to 1,400 ML/day. Elevated flows at Balranald have resulted from rain further upstream over the past month. Flows are expected to steadily recede over the remainder of July as the lower reaches of the Murrumbidgee River return to regulated conditions. The Murrumbidgee IVT balance is open for trade from the Murray to the Murrumbidgee (99.9 GL) but remains closed to trade from the Murrumbidgee to the Murray.

At Euston Weir, the weir pool level continues to target around 30 cm below FSL as part of the weir pool variability program. The downstream release remained above 14,000 ML/day this week and is expected to reach around 15,000 ML/day in the coming week.

Photo 2: Upper Murrumbidgee River at Tharwa (Photo courtesy Andy Lowes)

This week the Menindee Lakes storage decreased by 4 GL to 468 GL (27% capacity). The storage level will continue to ease over the coming weeks with no significant inflows currently forecast. The downstream release, measured at Weir 32, averaged around 240 ML/day over the past week. Despite the rainfall and streamflow responses during recent months, in many parts of NSW drought conditions persist with extensive water restrictions still in place. Links to drought services and assistance can be also accessed via the MDBA drought webpage

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Photo 3: Lake Pamamaroo (Photo Courtesy Craig Symonds, WaterNSW)

Photo 4: View of Lake Wetherell from the Pamamaroo inlet regulator (Photo Courtesy Craig Symonds, WaterNSW)

At Wentworth Weir, the weir pool level is being managed to target around FSL (30.80 m AHD) but is expected to vary 10 cm above and below this level as part of normal operations. The downstream release averaged around 14,000 ML/day and is expected to remain around this rate over the coming week.

This week, the Lake Victoria storage volume remained steady at 630 GL (93% capacity). The storage level in Lake Victoria will continue to be managed over the coming weeks in accordance with the Lake Victoria Operating Strategy. The strategy aims to fill the storage as late as possible while also holding a steady level for as short a time as possible to minimise erosion and inundation impacts on sensitive foreshore vegetation and cultural heritage material.

The flow to South Australia averaged 12,900 ML/day this week, as unregulated flows continued across the border. Flow to South Australia will remain above normal Entitlement into August as high flows continue to arrive from upstream. For more information on South Australia’s Entitlement flow, see the South Australian Department for Environment and Water’s latest River Murray flow report.

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The Lower Lakes 5-day average water level is currently 0.8 m AHD. The arrival of unregulated flows to the Lower Lakes has allowed around 65 GL to be released to the Coorong this week via Tauwitchere, Goolwa, Mundoo and Boundary Creek Barrages. Increased barrage releases will continue to be made when conditions allow to target outcomes in the Coorong. For information on barrage releases 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 22 Jul 2020

MDBA Storages Full

Supply Level

Full Supply Volume

Current Storage

Level Current Storage Dead

Storage Active

Storage

Change in Total Storage for the

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

Dartmouth Reservoir 486.00 3 856 452.95 2 044 53% 71 1 973 +12 Hume Reservoir 192.00 3 005 182.20 1 401 47% 23 1 378 +76 Lake Victoria 27.00 677 26.61 630 93% 100 530 -0 Menindee Lakes 1 731* 468 27% (- -) # 0 -4 Total 9 269 4 543 49% - - 3 881 +83 Total Active MDBA Storage 46% ^ Major State Storages

Burrinjuck Reservoir 1 026 453 44% 3 450 -2 Blowering Reservoir 1 631 1 010 62% 24 986 +32 Eildon Reservoir 3 334 1 713 51% 100 1 613 +24

* 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 21 Jul 2020 Storage Active Storage (GL) Weekly Change (GL) Diversion (GL) This Week From 1 May 2020 Lake Eucumbene - Total 916 -8 Snowy-Murray +23 328 Snowy-Murray Component 382 -17 Tooma-Tumut +4 77 Target Storage 1 170 Net Diversion 19 251 Murray 1 Release +30 409

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) 21.0 42 Yarrawonga Main Channel (net) 0.1 0 Wakool Sys Allowance 4.1 9 Torrumbarry System + Nyah (net) 0 0 Western Murray Irrigation 0.1 0 Sunraysia Pumped Districts 0.5 1 Licensed Pumps n/a 18 Licensed pumps - GMW (Nyah+u/s) 0 0 Lower Darling 0.0 0 Licensed pumps - LMW 1.7 3 TOTAL 25.2 69 TOTAL 2.3 4

* 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 unregulated flows and environmental flows.

Entitlement this month 108.5 * Flow this week 90.5 (12 900 ML/day) Flow so far this month 239.9 Flow last month 104.7

Salinity (EC) (microSiemens/cm at 25o C) Current Average over the last week Average since 1 August 2019 Swan Hill 110 110 80 Euston - - - Red Cliffs 120 120 60 Merbein 130 120 100 Burtundy (Darling) 330 320 560 Lock 9 110 110 100 Lake Victoria 130 130 120 Berri 140 130 160 Waikerie 170 210 220 Morgan 210 230 230 Mannum 320 310 260 Murray Bridge 300 300 290 Milang (Lake Alex.) 970 960 900 Poltalloch (Lake Alex.) 500 480 780 Meningie (Lake Alb.) 1 670 1 690 1 800 Goolwa Barrages 4 050 3 810 3 150

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River Levels and Flows Week ending Wednesday 22 Jul 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 - - - 6 890 F 4 970 5 300 Jingellic 4.0 2.29 208.81 9 830 R 8 790 10 020 Tallandoon ( Mitta Mitta River ) 4.2 1.86 218.75 1 760 F 1 690 2 130 Heywoods 5.5 1.44 155.07 600 S 600 600 Doctors Point 5.5 1.71 150.18 2 280 R 2 490 3 250 Albury 4.3 0.86 148.30 - - - - Corowa 4.6 0.79 126.81 2 270 F 2 870 3 280 Yarrawonga Weir (d/s) 6.4 1.25 116.29 7 410 R 8 970 9 310 Tocumwal 6.4 1.87 105.71 7 570 F 9 110 9 040 Torrumbarry Weir (d/s) 7.3 3.97 82.51 13 290 F 13 400 10 760 Swan Hill 4.5 2.34 65.26 13 520 R 12 040 10 900 Wakool Junction 8.8 4.12 53.24 13 520 R 12 750 12 700 Euston Weir (d/s) 9.1 2.46 44.30 14 730 R 14 370 14 960 Mildura Weir (d/s) - - 14 270 F 14 180 15 050 Wentworth Weir (d/s) 7.3 3.35 28.11 13 720 S 13 860 14 920 Rufus Junction - 4.33 21.26 12 220 R 12 510 11 740 Blanchetown (Lock 1 d/s) - 1.06 - 13 750 F 14 340 11 020 Tributaries Kiewa at Bandiana 2.8 1.91 155.14 1 850 R 1 990 2 650 Ovens at Wangaratta 11.9 9.40 147.08 4 720 F 5 560 7 200 Goulburn at McCoys Bridge 9.0 3.09 94.51 4 020 F 6 770 4 990 Edward at Stevens Weir (d/s) 5.5 0.86 80.64 570 F 550 770 Edward at Liewah - 1.69 57.07 1 020 F 1 230 1 080 Wakool at Stoney Crossing - 1.45 54.94 550 R 480 290 Murrumbidgee at Balranald 5.0 1.82 57.78 1 400 F 1 910 2 180 Barwon at Mungindi 6.1 3.21 - 140 F 140 200 Darling at Bourke 9.0 4.01 - 90 F 100 50 Darling at Burtundy Rocks - 0.71 - 160 S 160 170 Natural Inflow to Hume 9 710 10 730

(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 -0.18 - No. 7 Rufus River 22.10 +0.01 +2.01 No. 26 Torrumbarry 86.05 -0.23 - No. 6 Murtho 19.25 -0.01 +0.50 No. 15 Euston 47.60 -0.26 - No. 5 Renmark 16.30 +0.04 +0.59 No. 11 Mildura 34.40 +0.01 +0.51 No. 4 Bookpurnong 13.20 +0.16 +1.31 No. 10 Wentworth 30.80 -0.02 +0.71 No. 3 Overland Corner 9.80 +0.05 +0.74 No. 9 Kulnine 27.40 +0.01 -0.02 No. 2 Waikerie 6.10 +0.11 +0.75 No. 8 Wangumma 24.60 -0.60 +0.62 No. 1 Blanchetown 3.20 +0.16 +0.31

Lower Lakes FSL = 0.75 m AHD Lake Alexandrina average level for the past 5 days (m AHD) 0.80

Barrages Fishways at Barrages Openings Level (m AHD) No. Open Rock Ramp Vertical Slot 1 Vertical Slot 2 Dual Vertical Slots Goolwa 128 openings 0.82 4 - Open Open - Mundoo 26 openings 0.80 2 - - - Open Hunters Creek - - - - Open - - Boundary Creek 6 openings - 1 - Open - - Ewe Island 111 gates - All closed - - - Open Tauwitchere 322 gates 0.84 12 Open Open Open -

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

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Week ending Wednesday 22 Jul 2020

State Allocations (as at 22 Jul 2020)

NSW - Murray Valley Victorian - Murray Valley High security 97% General security 2%

High reliability 15% Low reliability 0%

NSW – Murrumbidgee Valley

Victorian - Goulburn Valley High security 95% General security 14%

High reliability 37% Low reliability 0%

NSW - Lower Darling

South Australia – Murray Valley High security 100% General security 30%

High security 77%

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

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

SA : http://www.environment.sa.gov.au/managing-natural-resources/river-murray