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Subscribe to the River Murray Weekly Report River Data website Water in Storages River Murray Weekly Report For the week ending Wednesday, 12 August 2020 Trim Ref: D20/32365 Rainfall and inflows There was widespread rain across the entire Murray-Darling Basin this week (Map 1). The Murrumbidgee catchment recorded the highest totals in the southern connected basin with Captains Flat, east of the ACT, recording 167 mm. Substantial rain and snow was also recorded over the Australian Alps, including 86 mm at Thredbo (just outside of the basin) and over the upper Lachlan River catchment where Crookwell also recorded 86 mm. Downstream of Hume Dam, Victorian catchments received moderate totals, with Mongan’s Bridge on the Kiewa River recording 52 mm over the weekend and the Ovens River at Rocky Point recording 16 mm for the same period. Map 1 - Murray-Darling Basin rainfall totals for week ending 12 August 2020 (Source: Bureau of Meteorology) There were modest streamflow responses in the mid-Murray tributaries following the rain this week. Tributary inflows from the Ovens, Kiewa and Goulburn Rivers remain sufficient to meet downstream flow requirements. The BoM is forecasting further widespread rain across the Murray-Darling Basin for the coming 8 days with totals of between 15 and 100 mm predicted across some areas of the southern connected basin. Further streamflow increases would be expected if the forecast rainfall eventuates. 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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Page 1: River Murray Weekly Report · 8/12/2020  · River Murray Weekly Report Subscribe to the River Murray Weekly Report River Data website Water in Storages The Lower Lakes 5-day average

Subscribe to the River Murray Weekly Report River Data website Water in Storages

River Murray Weekly Report For the week ending Wednesday, 12 August 2020

Trim Ref: D20/32365

Rainfall and inflows There was widespread rain across the entire Murray-Darling Basin this week (Map 1). The Murrumbidgee catchment recorded the highest totals in the southern connected basin with Captains Flat, east of the ACT, recording 167 mm. Substantial rain and snow was also recorded over the Australian Alps, including 86 mm at Thredbo (just outside of the basin) and over the upper Lachlan River catchment where Crookwell also recorded 86 mm. Downstream of Hume Dam, Victorian catchments received moderate totals, with Mongan’s Bridge on the Kiewa River recording 52 mm over the weekend and the Ovens River at Rocky Point recording 16 mm for the same period.

Map 1 - Murray-Darling Basin rainfall totals for week ending 12 August 2020 (Source: Bureau of Meteorology)

There were modest streamflow responses in the mid-Murray tributaries following the rain this week. Tributary inflows from the Ovens, Kiewa and Goulburn Rivers remain sufficient to meet downstream flow requirements. The BoM is forecasting further widespread rain across the Murray-Darling Basin for the coming 8 days with totals of between 15 and 100 mm predicted across some areas of the southern connected basin. Further streamflow increases would be expected if the forecast rainfall eventuates.

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 Murray Weekly Report

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System operations Unregulated flow event Heavy rainfall in late April soaked catchments and boosted tributary inflows from the Ovens, Kiewa and Goulburn Rivers. Catchments have been responsive since, with healthy tributary inflows continuing during May, June, July and now, into early August. These inflows have provided more than enough water to supply system requirements and allowed releases from Hume Dam to be maintained at the minimum release of 600 ML/day since late April.

The tributary inflows have also resulted in the effective filling of Lake Victoria and a period of unregulated flows into South Australia since 27 June. Despite the relatively modest streamflow responses during the last week, an associated reduction in losses and demands has meant that sufficient surplus water remains in the River Murray for the unregulated event to continue in reaches just upstream of Lake Victoria until 18 August.

Whilst unregulated flows continue, Lake Victoria will be operated at levels below full supply and in accordance with the Lake Victoria Operating Strategy. This means that if additional rain and upstream tributary inflow results in another extension to unregulated flows, the level may be further reduced to help minimise the impacts of inundation on the vegetation and sensitive cultural heritage material on the lake shore. The lake will be re-filled as is required at the conclusion of the unregulated event. For more information on the expected duration and the river reaches where unregulated flow currently applies, please refer to your local water authority.

Photo 1: Molonglo River (near Queanbeyan). Photo courtesy Neve McLean.

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River Murray Weekly Report

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River operations

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, physical 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 upstream of Euston Weir. 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.

River operations Over the past week, MDBA total active storage increased by 98 GL to 4,143 GL (49% capacity). Whilst the water currently stored in the Menindee Lakes remains below 640 GL, it is unavailable for MDBA use. Therefore, the total active storage percentage remains lower than the total current storage (52%) which includes the Menindee Lakes.

At Dartmouth Reservoir, the storage increased by 18 GL this week to 2,069 GL (54% capacity) following rainfall in the upstream catchments. The release, measured at Colemans, targeted the minimum flow of 200 ML/day across the week.

At Hume Reservoir, downstream tributary inflows from the Ovens, Kiewa and Goulburn Rivers continue to meet Murray demands which has enabled the Hume release to be maintained at the minimum release of 600 ML/day. This, combined with reasonable inflows to Hume, due in part to rainfall during the week, has resulted in a 55 GL increase in the storage to 1,597 GL (53% capacity). Hume Reservoir is expected to continue to rise in coming weeks should the forecast rain eventuate.

At Lake Mulwala, the pool level is currently near 124.8 m AHD, which is within the normal operating range between 124.6 and 124.9 m AHD. During the week diversion to Mulwala Canal decreased from 250 ML/day until ceasing mid-week. The diversion into Yarrawonga Main Channel averaged around 200 ML/day and is expected to decrease over the coming days. The release from Yarrawonga Weir was gradually increased from 4,000 ML/day at the start of the week to the current release of around 5,800 ML/day to accommodate the streamflow responses from the Ovens and Kiewa Rivers, and to manage the weir pool in preparation for forecast rain in the coming week.

In the Barmah-Millewa Forest, a number of regulators will be opened over the coming week. Forest managers will co-ordinate the opening of the regulators on behalf of environmental water holders, to provide connectivity between the river and the floodplain in winter and into spring while river flows are within channel capacity. This action will increase habitat for native fish and improve the transfer of valuable nutrients from the floodplain to the river. These nutrients are the base of a food web that supports the entire river ecosystem including algae, aquatic plants, macroinvertebrates, turtles, fish, platypus and birds. The water used in the forest will be debited from environmental water accounts.

The gates at Edward and Gulpa Creek offtake regulators are raised clear of the water, allowing inflows to the Edward River to vary with the Murray. Flows through the Edward and Gulpa offtakes are currently near 850 and 230 ML/day, respectively. At Stevens Weir, the downstream flow averaged around 650 ML/day and may increase over the coming week.

• Minimum releases from Hume Dam continue as tributary inflows meet downstream requirements • Flows along mid-Murray receive modest streamflow response following rain • Unregulated flow event continues for reaches just upstream of Lake Victoria

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River Murray Weekly Report

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Photo 2: Eurobin Creek, from Noonameena Bridge (Ovens catchment). Photo courtesy Hugo Bowman, MDBA. Back on the River Murray, the flow at Barmah has gradually increased to around 3,650 ML/day. Inflows from the Broken Creek, measured at Rice’s Weir, increased to average around 240 ML/day this week. Maintenance works in the irrigation district have now finished and water is being delivered from irrigation outfalls on behalf of environmental water holders. The Waranga Basin, near Goulburn Weir, is now effectively full and it is expected that potentially elevated flows from further forecast rain will be passed through Goulburn Weir to the River Murray.

On the Goulburn River, the flow measured at McCoys Bridge increased from around 1,600 ML/day to the current rate near 3,300 ML/day and may increase further over the coming days should the forecast rain eventuate. 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.

Diversions to National Channel from the Torrumbarry Weir pool decreased from 1,500 ML/day to 800 ML/day this week. The diversion may increase again over the coming week with the irrigation season commencing on August 15, however the forecast rain may postpone the potential rise. The Torrumbarry Weir pool was returned to the Full Supply Level (FSL) of 86.05 m/AHD over the past week, ready for the commencement of the Victorian irrigation season. This week the release from Torrumbarry Weir gradually increased to a current flow of near 4,900 ML/day and is expected to continue to increase in the coming days as streamflow responses from recent rain move through the system.

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River Murray Weekly Report

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Inflow from the Murrumbidgee River, measured at Balranald, remained steady at an average of just over 1,100 ML/day this week and is anticipated to increase slightly over the coming week. 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. Supplementary access for the Murrumbidgee River and Yanco/Billabong Creek systems was announced this week after significant rain and flow increases were observed along the upper Murrumbidgee and its tributaries (Photos 1, 3 and 4). See the WaterNSW website for more information.

Photos 3&4: The Murrumbidgee River from Shepherds Lookout (ACT). Photo 2, following some early April rain, and photo 3, following last week’s rain. Photo courtesy Tim Rossi, MDBA. At Euston Weir, the weir pool level is gradually being returned to FSL over the coming weeks. The downstream release decreased slowly to around 7,300 ML/day and may continue to fall slightly over the coming week.

This week the Menindee Lakes storage decreased by 1 GL to 459 GL (27% capacity). The downstream release, measured at Weir 32, averaged around 260 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.

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 flow reduced from a high of 11,500 ML/day at the start of the week to near 9,000 ML/day currently and may reduce further over the coming week.

The Lock 9 weir pool continues to vary just above FSL. Lock 8 has been gradually increasing towards FSL this week. The level is now 10 cm below FSL and will gradually increase towards FSL over the coming days. The Lock 7 weir pool continues to vary near FSL.

Lake Victoria increased by 26 GL to 671 GL (99% capacity) this week and the storage is now considered effectively full. Should forecast rainfall lead to renewed inflows, it is possible that Lake Victoria may be actively drawn down in 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 around 5,500 ML/day before increasing sharply at the end of the week to a current rate of near 12,000 ML/day. The current flow remains above August entitlement (4,000 ML/day) due in part to ongoing unregulated flows attributed to modest streamflow responses during the last week, and an associated reduction in losses and demands. Flows may decrease somewhat during the coming week but will likely remain at an elevated rate, particularly if further rain and inflow takes place.

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River Murray Weekly Report

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The Lower Lakes 5-day average water level is currently 0.80 m AHD. The arrival of unregulated flows to the Lower Lakes allowed around 200 GL to be released to the Murray Mouth and Coorong during July via Tauwitchere, Goolwa, Mundoo, Ewe Island and Boundary Creek Barrages. Increased barrage releases will continue to be made during August when conditions allow to target outcomes in 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 REYNOLDS Executive Director, River Management

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River Murray Weekly Report

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Water in Storage Week ending Wednesday 12 Aug 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 3 856 453.50 2 069 54% 71 1 998 +18 Hume Reservoir 192.00 3 005 183.67 1 597 53% 23 1 574 +55 Lake Victoria 27.00 677 26.96 671 99% 100 571 +26 Menindee Lakes 1 731* 459 27% (- -) # 0 -1 Total 9 269 4 796 52% - - 4 143 +98 Total Active MDBA Storage 49% ^ Major State Storages

Burrinjuck Reservoir 1 026 719 70% 3 716 +234 Blowering Reservoir 1 631 1 115 68% 24 1 091 +38 Eildon Reservoir 3 334 1 734 52% 100 1 634 +16

* 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 11 Aug 2020 Storage Active Storage (GL) Weekly Change (GL) Diversion (GL) This Week From 1 May 2020 Lake Eucumbene - Total 928 +4 Snowy-Murray +15 394 Snowy-Murray Component 377 +2 Tooma-Tumut +3 86 Target Storage 1 190 Net Diversion 12 308 Murray 1 Release +18 488

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) -0.2 64 Yarrawonga Main Channel (net) 1.4 4 Wakool Sys Allowance 2.3 18 Torrumbarry System + Nyah (net) 0 0 Western Murray Irrigation 0.0 0 Sunraysia Pumped Districts 0.1 3 Licensed Pumps 0.9 22 Licensed pumps - GMW (Nyah+u/s) 0.3 1 Lower Darling 0.0 0 Licensed pumps - LMW 0.6 8 TOTAL 3.0 104 TOTAL 2.4 16

* 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.

Entitlement this month 124.0 * Flow this week 43.1 (6 200 ML/day) Flow so far this month 92.9 Flow last month 358.2

Salinity (EC) (microSiemens/cm at 25o C) Current Average over the last week Average since 1 August 2020 Swan Hill 120 120 120 Euston - - - Red Cliffs 130 130 120 Merbein - - 120 Burtundy (Darling) 340 350 350 Lock 9 120 120 120 Lake Victoria 120 120 120 Berri 150 140 140 Waikerie 190 180 190 Morgan 170 190 210 Mannum 190 200 210 Murray Bridge 240 250 260 Milang (Lake Alex.) 990 980 960 Poltalloch (Lake Alex.) 380 410 410 Meningie (Lake Alb.) 1 680 1 690 1 710 Goolwa Barrages 1 440 1 470 1 470

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River Levels and Flows Week ending Wednesday 12 Aug 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 - - - 2 950 R 3 330 3 760 Jingellic 4.0 1.84 208.36 5 780 F 6 170 9 620 Tallandoon ( Mitta Mitta River ) 4.2 1.51 218.40 770 F 830 1 460 Heywoods 5.5 1.39 155.02 600 S 600 600 Doctors Point 5.5 1.68 150.15 2 060 R 1 920 1 700 Albury 4.3 0.83 148.27 - - - - Corowa 4.6 0.73 126.75 2 100 F 1 930 1 810 Yarrawonga Weir (d/s) 6.4 0.95 115.99 5 420 S 4 660 4 020 Tocumwal 6.4 1.42 105.26 4 740 R 4 090 3 790 Torrumbarry Weir (d/s) 7.3 1.65 80.20 4 310 R 3 880 6 490 Swan Hill 4.5 0.96 63.88 4 300 R 4 970 8 560 Wakool Junction 8.8 2.55 51.67 6 120 F 7 650 10 510 Euston Weir (d/s) 9.1 1.48 43.32 8 020 F 9 750 12 560 Mildura Weir (d/s) - - 9 620 F 10 390 14 240 Wentworth Weir (d/s) 7.3 3.13 27.89 9 270 F 9 910 13 690 Rufus Junction - 4.00 20.93 9 910 R 5 770 10 240 Blanchetown (Lock 1 d/s) - 0.68 - 5 790 F 6 850 11 050 Tributaries Kiewa at Bandiana 2.8 1.82 155.05 1 680 R 1 540 1 290 Ovens at Wangaratta 11.9 8.74 146.42 2 590 F 2 700 2 790 Goulburn at McCoys Bridge 9.0 2.51 93.93 2 900 R 1 680 3 080 Edward at Stevens Weir (d/s) 5.5 0.99 80.76 690 F 660 660 Edward at Liewah - 1.54 56.92 900 R 870 720 Wakool at Stoney Crossing - 1.48 54.97 620 S 580 490 Murrumbidgee at Balranald 5.0 1.58 57.54 1 160 S 1 130 830 Barwon at Mungindi 6.1 3.18 - 120 R 120 120 Darling at Bourke 9.0 4.15 - 730 R 570 390 Darling at Burtundy Rocks - 0.72 - 170 S 170 160 Natural Inflow to Hume 8 050 7 160

(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 -0.09 - No. 7 Rufus River 22.10 +0.04 +1.69 No. 26 Torrumbarry 86.05 -0.01 - No. 6 Murtho 19.25 +0.07 +0.27 No. 15 Euston 47.60 -0.13 - No. 5 Renmark 16.30 +0.10 +0.42 No. 11 Mildura 34.40 +0.05 +0.28 No. 4 Bookpurnong 13.20 +0.21 +0.91 No. 10 Wentworth 30.80 +0.00 +0.49 No. 3 Overland Corner 9.80 +0.04 +0.40 No. 9 Kulnine 27.40 +0.09 -0.07 No. 2 Waikerie 6.10 +0.18 +0.31 No. 8 Wangumma 24.60 -0.18 +0.23 No. 1 Blanchetown 3.20 +0.14 -0.07

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 0.79 3 - Open Open - Mundoo 26 openings 0.73 1 - - - Open Hunters Creek - - - - Open - - Boundary Creek 6 openings - 1 - Open - - Ewe Island 111 gates - All closed - - - Open Tauwitchere 322 gates 0.82 5 Open Closed Open -

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

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Week ending Wednesday 12 Aug 2020

State Allocations (as at 12 Aug 2020)

NSW - Murray Valley Victorian - Murray Valley High security 97% General security 3%

High reliability 19% Low reliability 0%

NSW – Murrumbidgee Valley

Victorian - Goulburn Valley High security 95% General security 16%

High reliability 37% Low reliability 0%

NSW - Lower Darling

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

High security 81%

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