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River Murray Weekly Report For the week ending Wednesday, 8 April 2020

Trim Ref: D20/11758

Rainfall and inflows Rainfall was widespread across the Murray-Darling Basin this week (Map 1). High totals were recorded along the slopes and ranges in central and eastern NSW, and along the Southern NSW and Victorian Alps. Areas of central Victoria also recorded high totals. SA and southern Queensland recorded more modest rainfall. In NSW, high totals included 92 mm at Cobar in the Upper West region and 79 mm at Cabramurra on the Southwest Slopes. In Victoria highest totals included 162 mm at Mount Buffalo in the Northeast, 150 mm at Mount Buller and 113 mm at Inglewood in the Loddon Catchment.

Map 1 – Rainfall across the Murray-Darling Basin for the week ending 8 April 2020. Source: Bureau of Meteorology.

Positive stream flow responses were observed in the upper Murray tributaries following the rainfall this week. Specific information about flows at key locations in the upper Murray catchment including Hinnomunjie Bridge on the upper Mitta Mitta River, Biggara on the upper Murray, Bandiana on the Kiewa River as well as Peechelba on the Ovens River 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 at Bureau of Meteorology’s (BoM) website and in the Murray River Basin daily river report at the WaterNSW website.

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River operations

River operations and the COVID-19 virus The MDBA is continuing to work with government partners and stakeholders effectively 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. All MDBA operations and business are continuing as normal. River operations have been identified as a priority in this time as running the river is essential to supporting irrigation supply to agricultural industries.

Across the system, all WaterNSW Dams and Recreation areas are closed to public access until further notice. In Victoria, caravan parks and camping areas are closed with houseboating considered non-essential activity. We hope all our community members remain safe at this time.

Traditionally the Easter weekend has seen many people flock to the Murray. 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 Bushfire impacts - The MDBA and State Constructing Authorities are continuing to monitor water quality in areas affected by the summer bushfires in the upper Murray catchment, particularly following rainfall events. Mobilised ash and sediment have been observed in Lake Hume.

A significant risk to water quality remains from ash and sediment washing into the lake from bushfire affected areas. Re-growth of vegetation in less severely burnt areas is helping to reduce this risk through soil stabilisation. This process will take time and it is still possible that further fish deaths may result from poor water quality, particularly following intense rainfall.

For information on current water quality and any impacts to your water supply, contact your retail water supplier.

Blue-green algal alerts are in place at several locations in the River Murray system. WaterNSW has advised that the alert status at Hume Dam remains at amber, however a cautionary warning remains in place for the Murray arm as surface scums persist. Red alerts are in place for the River Murray at Corowa, within and directly downstream of Lake Mulwala/Yarrawonga Weir, Cobram, Tocumwal and Picnic Point, on the Gulpa Creek at Mathoura and the Edward River at Deniliquin. A Red Alert has been declared for Echuca/Moama. Further downstream on the lower River Murray, a red alert is still current at Buronga/Mildura. The Red Alert between Merbein and Lock 9 has now been lifted. 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 25 GL to 2,250 GL (27% capacity).

At Dartmouth Reservoir, the storage increased by 7 GL to 1,806 GL (47% capacity) following rainfall. The release from Dartmouth, measured at Colemans, pulsed to around 2,000 ML/day as AGL released entitlement water for hydroelectricity generation at the start of the week, before reducing down towards around 250 ML/day.

At Hume Reservoir, the storage increased by 18 GL to 406 GL (14% capacity). The release from Hume decreased from around 7,000 ML/day to around 1,300 ML/day at the end of the week to accommodate increased inflows from downstream tributaries following last week’s rainfall.

• Blue – green algae alerts current at several locations in the River Murray system • Flows have restarted in the Lower Darling downstream of Weir 32 and reached Pooncarie

Weir on Tuesday • Wentworth weir pool to by lowered by 20-30 cm below Fully Supply Level (FSL) to assist with

the movement of any poor-quality water through the weir pool

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Photo 1 – Mountain Creek in the Upper Kiewa Catchment (photo courtesy Hugo Bowman)

At Lake Mulwala, the pool level is currently 124.78 m AHD, which is within the normal operating range between 124.6 and 124.9 m AHD. At Yarrawonga Main Channel, diversions averaged around 250 ML/day. The diversion into Mulwala Canal eased from around 800 ML/day to 450 ML/day.

The release from Yarrawonga Weir gradually decreased from 7,000 ML/day to 6,000 ML/day over the week. This marks the end of a fortnight of increased releases to assist irrigators in the Mid-Murray with access to water. The reduction in flow downstream of Yarrawonga Weir allows more water resource to be preserved in upstream storages, benefiting users along the length of the River Murray System by maximising the water available in the coming water year.

Flows through the Edward River offtake remained near 1,100 ML/day. Flow through the Gulpa Creek offtake averaged 200 ML/day. Downstream along the Edward River, diversion through the Wakool offtake regulator averaged 200 ML/day, 200 ML/day through Yallakool Creek offtake and 180 ML/day into Colligen Creek. At Stevens Weir, the downstream flow decreased to an of average 900 ML/day and is forecast to gradually fall over the coming week.

Flow in the Goulburn River measured at McCoys Bridge increased from around 1,000 ML/day to around 2,650 ML/day following weekend rainfall. Flows are expected to decrease and target around 940 ML/day over the coming week. The MDBA has ceased the call on Goulburn Valley Inter Valley Trade (IVT). Environmental water is now being delivered on behalf of the Victorian Environmental Water Holder to achieve ecological objectives in the lower Goulburn River.

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While delivery of Goulburn Valley IVT is not currently required to meet Murray system demands, further IVT delivery could still be called over the remainder of the irrigation season if demands increase. 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 averaged around 1,950 ML/day over the week to meet higher demands in the Torrumbarry irrigation district. The Torrumbarry Weir pool remains at the Full Supply Level (FSL) of 86.05 m AHD. Flow downstream of Torrumbarry Weir averaged 5,000 ML/day and is forecast to fall over the coming week.

Photo 2 – Kiewa River West Branch (photo courtesy Hugo Bowman)

Lower river levels than those experienced over recent Easter and autumn school holiday periods are expected in the mid-Murray this year. Although flows are expected to remain above minimum operating levels at key gauges such as Swan Hill, community members, including river pumpers and boat owners and operators, should be aware of changing river levels in case adjustments need to be made to pumps, moorings or recreational activities.

Inflow from the Murrumbidgee River, measured at Balranald, reduced from around 400 ML/day to 200 ML/day. The delivery of Murrumbidgee IVT ceased in March. The Murrumbidgee IVT balance is currently 41 GL and trade into and out of the valley is open. Further information on expected IVT deliveries from the Murrumbidgee is provided by WaterNSW.

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. Photo 3 – Flow in the Upper Murrumbidgee river near the ACT/NSW border following this weekend’s rainfall (photo courtesy Tim Rossi, MDBA)

At Euston, the weir pool level is currently targeting FSL. Euston weir pool is planned to be gradually lowered from around mid-April to target 20 to 30 cm below FSL. The exact timing is dependent on inflows to the Murray from the lower Darling River and aims to deliver additional flow downstream to Wentworth Weir to help manage water quality impacts in the Murray associated with restarting flows in the lower Darling River. Euston pool level will remain around 20 to 30 cm below FSL over coming months as part of the weir pool variability program. Varying pool levels helps restore a more natural wetting and drying cycle to riverbanks and adjacent wetlands within the influence of the weir pool. Over the past week the downstream release increased from around 4,300 ML/day to around 5,800 ML/day.

This week, the Menindee Lakes storage increased by 36 GL to 244 GL (14% capacity). WaterNSW has been providing updates on the streamflow response in the Barwon-Darling system in recent weeks and currently forecasts a volume in the order of 395 GL and 425 GL will flow into the Menindee Lakes. Due to the very dry conditions preceding these flows and long travel times, some uncertainty remains as to the volume of water that will ultimately reach Menindee Lakes from this event.

WaterNSW is diverting water from Lake Wetherell to Lake Pamamaroo (now storing 77 GL). Flow through the Pamamaroo inlet is currently 4,000 ML/day. The release from Lake Wetherell to Weir 32 decreased slightly this week from 3,000 ML/day to 2,500 ML/day. The flow in the Lower Darling River has now reached Pooncarie, just over half way from Menindee to Wentworth It is expected that the flow will arrive at Burtundy around 11 or 12 April before reaching the Wentworth Weirpool on 13 or 14 April. More information about releases from the Menindee Lakes over the coming week can be found here.

Despite recent rainfall and streamflow responses, in many parts of NSW drought conditions persist with extensive water restrictions. Links to drought services and assistance can be also accessed via the MDBA drought webpage.

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At Wentworth Weir, the pool level is currently 10 cm above FSL. The release downstream has increased over the week from 2,700 ML/day to around 4,800 ML/day and is forecast to remain around this rate over the coming week. The MDBA is working closely with WaterNSW and SA Water to manage water quality impacts in the Darling arm of the Wentworth Weir pool and the River Murray associated with the arrival of renewed flows from the lower Darling River. This includes the lowering of the weir pool to assist in the passage of any poor-quality water arriving from upstream, particularly with the head of the flow pulse.

River users are advised to adjust their activities, pumps and moorings to accommodate the change in weir pool level. At this stage the pool is expected to start dropping from about 10 April. The level will fall by around 5-7 cm per day, with the pool to be lowered by up to 30 cm below FSL. It is forecast that any slug of higher salinity water may take in the order of 8-12 days to move through the Darling arm of the Wentworth Weir pool and into the River Murray.

The Lock 9 weir pool level is currently targeting FSL to 10 cm below FSL. At Locks 8 and 7, the weir pool levels are being varied as part of the weir pool variability program. Currently, Lock 8 is targeting a level between 90 and 100 cm below FSL and Lock 7 is targeting a level between 50 and 60 cm below FSL.

In addition to lowering the Wentworth weir pool, the Lock 7 weir pool will be raised back to FSL over the coming weeks, with further variation of the level at Lock 8 also being considered. Increasing the volumes of water stored in these weir pools will assist with the dilution of any poor-quality water originating from the restart of the lower Darling River as it flows into the Murray. It will also provide operational flexibility in delivering flow to South Australia. Further information on variations to the levels at Lock 8 will be provided in the next edition of the weekly report.

At Lake Victoria, the storage volume remained steady at 232 GL (34% capacity).

The flow to South Australia averaged 4,100 ML/day and will remain around 4,000 ML/d over the coming week. This flow comprises the delivery of South Australia’s Monthly Entitlement, trade and environmental water delivery. For more information on South Australia’s Entitlement flow, see the South Australian Department for Environment and Water’s latest River Murray flow report.

The Lower Lakes 5-day average water level is currently 0.52 m AHD. Releases have been occurring through fishways and small releases through Tauwitchere barrage when conditions allow. 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 08 Apr 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 3 856 447.42 1 806 47% 71 1 735 +7 Hume Reservoir 192.00 3 005 172.27 406 14% 23 383 +18 Lake Victoria 27.00 677 22.84 232 34% 100 132 +0 Menindee Lakes 1 731* 244 14% (- -) # 0 +36 Total 9 269 2 688 29% - - 2 250 +62 Total Active MDBA Storage 27% ^ Major State Storages

Burrinjuck Reservoir 1 026 382 37% 3 379 +7 Blowering Reservoir 1 631 745 46% 24 721 +18 Eildon Reservoir 3 334 1 204 36% 100 1 104 +12

* 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 07 Apr 2020 Storage Active Storage (GL) Weekly Change (GL) Diversion (GL) This Week From 1 May 2019 Lake Eucumbene - Total 778 n/a Snowy-Murray +11 416 Snowy-Murray Component 486 n/a Tooma-Tumut +7 206 Target Storage 1 340 Net Diversion 5 210 Murray 1 Release +22 602

Major Diversions from Murray and Lower Darling (GL) * New South Wales This Week From 1 July 2019 Victoria This Week From 1 July 2019 Murray Irrig. Ltd (Net) 3.0 130 Yarrawonga Main Channel (net) 1.7 113 Wakool Sys Allowance 1.0 48 Torrumbarry System + Nyah (net) 0 254 Western Murray Irrigation 0.1 23 Sunraysia Pumped Districts 0.3 102 Licensed Pumps 1.7 122 Licensed pumps - GMW (Nyah+u/s) 0.8 22 Lower Darling 0.0 1 Licensed pumps - LMW 1.8 370 TOTAL 5.8 324 TOTAL 4.6 861

* 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 includes monthly Entitlement plus the delivery of environmental and traded water.

Entitlement this month 135.0 * Flow this week 28.6 (4 100 ML/day) Flow so far this month 33.2 Flow last month 171.6

Salinity (EC) (microSiemens/cm at 25o C) Current Average over the last week Average since 1 August 2019 Swan Hill 70 80 70 Euston - - - Red Cliffs 40 40 50 Merbein 120 110 90 Burtundy (Darling) - - 1 220 Lock 9 100 100 100 Lake Victoria 140 140 120 Berri 160 150 140 Waikerie 210 210 210 Morgan 220 210 220 Mannum 250 240 260 Murray Bridge 270 280 280 Milang (Lake Alex.) 960 960 870 Poltalloch (Lake Alex.) 900 890 820 Meningie (Lake Alb.) 2 010 2 030 1 780 Goolwa Barrages 4 080 5 910 2 120

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River Levels and Flows Week ending Wednesday 08 Apr 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 - - - 4 820 F 3 490 2 410 Jingellic 4.0 - - 7 700 S 5 660 2 870 Tallandoon ( Mitta Mitta River ) 4.2 1.48 218.37 710 F 1 070 640 Heywoods 5.5 1.76 155.39 1 300 F 3 150 7 300 Doctors Point 5.5 1.86 150.33 3 100 R 4 230 8 380 Albury 4.3 0.99 148.43 - - - - Corowa 4.6 1.04 127.06 3 240 F 5 430 8 060 Yarrawonga Weir (d/s) 6.4 1.04 116.08 5 980 F 6 550 7 230 Tocumwal 6.4 1.63 105.47 5 940 R 6 310 6 890 Torrumbarry Weir (d/s) 7.3 1.92 80.46 5 240 R 4 980 4 520 Swan Hill 4.5 1.09 64.01 5 180 S 4 930 3 830 Wakool Junction 8.8 2.52 51.64 6 020 R 5 730 4 470 Euston Weir (d/s) 9.1 1.16 43.00 5 830 R 5 450 4 190 Mildura Weir (d/s) - - 5 380 F 4 420 4 290 Wentworth Weir (d/s) 7.3 2.73 27.49 4 830 R 4 070 3 510 Rufus Junction - 2.95 19.88 3 650 S 3 720 4 400 Blanchetown (Lock 1 d/s) - 0.54 - 2 930 R 2 950 2 760 Tributaries Kiewa at Bandiana 2.8 1.75 154.98 1 560 R 790 270 Ovens at Wangaratta 11.9 8.89 146.57 3 080 F 2 530 410 Goulburn at McCoys Bridge 9.0 2.38 93.80 2 650 R 1 300 950 Edward at Stevens Weir (d/s) 5.5 1.15 80.93 880 S 930 810 Edward at Liewah - 1.56 56.94 910 R 870 880 Wakool at Stoney Crossing - 1.36 54.86 370 R 360 330 Murrumbidgee at Balranald 5.0 0.47 56.43 210 F 280 630 Barwon at Mungindi 6.1 3.25 - 170 F 210 350 Darling at Bourke 9.0 4.45 - 2 770 F 4 640 9 930 Darling at Burtundy Rocks - 0.50 - 0 F 0 0 Natural Inflow to Hume 4 040 600

(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 -0.12 - No. 7 Rufus River 22.10 -0.56 +0.64 No. 26 Torrumbarry 86.05 +0.00 - No. 6 Murtho 19.25 +0.00 +0.00 No. 15 Euston 47.60 +0.03 - No. 5 Renmark 16.30 +0.01 +0.18 No. 11 Mildura 34.40 +0.00 +0.14 No. 4 Bookpurnong 13.20 +0.10 +0.43 No. 10 Wentworth 30.80 +0.09 +0.09 No. 3 Overland Corner 9.80 +0.10 +0.24 No. 9 Kulnine 27.40 -0.10 -0.97 No. 2 Waikerie 6.10 +0.13 +0.16 No. 8 Wangumma 24.60 -0.99 -0.49 No. 1 Blanchetown 3.20 +0.11 -0.21

Lower Lakes FSL = 0.75 m AHD Lake Alexandrina average level for the past 5 days (m AHD) 0.51

Barrages Fishways at Barrages Openings Level (m AHD) No. Open Rock Ramp Vertical Slot 1 Vertical Slot 2 Dual Vertical Slots Goolwa 128 openings 0.58 All closed - Closed Open - Mundoo 26 openings 0.55 All closed - - - Open Hunters Creek - - - - Open - - Boundary Creek 6 openings - All closed - Open - - Ewe Island 111 gates - All closed - - - Open Tauwitchere 322 gates 0.55 1 Open Open Open -

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

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Week ending Wednesday 08 Apr 2020

State Allocations (as at 08 Apr 2020)

NSW - Murray Valley Victorian - Murray Valley High security 97% General security 0%

High reliability 66% Low reliability 0%

NSW – Murrumbidgee Valley

Victorian - Goulburn Valley High security 95% General security 6%

High reliability 80% Low reliability 0%

NSW - Lower Darling

South Australia – Murray Valley High security 100% General security 0%

High security 100%

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