RIVER MURRAY WEEKLY REPORTFOR THE WEEK ENDING WEDNESDAY, 14TH DECEMBER 2023Trim Ref: D16/44914

Rainfall and inflowsWhilst rainfall was recorded across most of the Murray-Darling Basin this week, moderate falls were mainly confined to the far north of the Basin and areas of the Great Dividing Range (see Map 1). In Queensland the heaviest falls included 36 mm at Munnaweena in the Maranoa catchment and 35 mm at Wallen in the Warrego catchment. In New South Wales, Nundle on the northwest slopes and Gundagai on the southwest slopes both recorded 38 mm. Further south in north east Victoria, 58 mm was recorded at Woods Point and 51 mm at Mount Buller AWS. In South Australia, 21 mm was recorded at Mount Barker.

Map 1 - Murray-Darling Basin rainfall week ending 14th December 2016 (Source: Bureau of Meteorology)

Relatively modest rainfall in the upper Murray catchments provided only short-lived flow increases this week. At Hinnomunjie, on the Mitta Mitta River upstream of Dartmouth Reservoir, the flow peaked at 1,350 ML/day and has receded to 560 ML/day. Biggara on the upper Murray briefly reached 950 ML/day before receding to 650 ML/day. The flow in the Ovens River at Wangaratta peaked close to 2,400 ML/day before receding to 1,600 ML/day.

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River operations Release downstream of Yarrawonga to gradually recede over the coming weeks Weirs on the River Murray in Victoria and New South Wales are being reinstated as the floods

pass downstream into South Australia

Hypoxic ‘blackwater’ continues to be recorded in the lower Murray around Mildura and downstream into South Australia. As is occurring upstream around Euston, dissolved oxygen readings are expected to improve as river levels return to within the channel and the volume of water returning from the floodplain reduces. Also, reinstatement of the weirs at Euston and further downstream will help improve oxygen levels in water passing over these weirs.

Blackwater occurs naturally when there is rapid breakdown of leaf litter from inundated areas. Breakdown of leaf litter is an important ecological process which provides nutrients for the growth of aquatic organisms. However, as is occurring now, this process can result in very low levels of dissolved oxygen resulting in fish deaths. The MDBA, together with New South Wales, Victorian and South Australian agencies, will continue to monitor dissolved oxygen levels.

MDBA total storage appears to have peaked this week, increasing by only 22 GL to 7,408 GL (86% capacity). This compares with the long-term average total active storage in mid-December of around 6,450 GL. Without further significant rain, total storage will fall away over the coming months as demands continue to increase.

At Dartmouth Reservoir, the storage volume increased by 11 GL this week, to 2,984 GL (77% capacity). The release remains at the minimum flow of 200 ML/day at Colemans gauge.

The storage volume at Hume Reservoir decreased by 34 GL this week to 2,848 GL (95% capacity). Release from Hume Reservoir increased over the week from 13,200 ML/day to 16,000 ML/day.

At Yarrawonga Weir, diversions at the major irrigation off-takes are at relatively low rates for this time of year, considering New South Wales general security and Victorian high reliability water allocations in the Murray are at 100%. Diversions at Mulwala Canal are currently 3,800 ML/day compared with the channel capacity of around 10,000 ML/day. Diversions at Yarrawonga Main Chanel are currently 1,350 ML/day compared with the channel capacity of around 3,000 ML/day. The release downstream of the weir has averaged around 15,000 ML/day over the last few weeks. These flows include environmental water which is aiming to provide benefits in Barmah-Millewa Forest and at sites further downstream. The release will be gradually reduced in the coming weeks and is expected to fall to around 8,000 ML/day by early January 2017. During 2017, system demands downstream of the Barmah Choke will be supplemented by large volumes of water traded from the Goulburn and Murrumbidgee valleys and water currently available in Menindee lakes. This means that flow rates downstream of Yarrawonga during the remainder of summer are likely to be lower compared with rates experienced last summer when flows were mostly around channel capacity.

Flows through the Edward River offtake have remained near 1,600 ML/day while the Gulpa Creek offtake has slowly receded to 570 ML/day. The flow at Toonalook on the Edward River has held steady at around 4,300 ML/day. Downstream of Stevens Weir, the flow has averaged around 1,950 ML/day.

Inflows to the Murray from the Goulburn River are currently around 1,000 ML/day. These flows are being supplemented by the addition of around 600 ML/day of environmental water.

The flow at Torrumbarry Weir has reduced from 8,150 ML/day to around 7,500 ML/day, and is expected to remain around this rate over the coming week. Diversions through National Channel are currently near 3,000 ML/day.

The flow at Swan Hill continues to recede, falling from 9,400 ML/day to 8,100 ML/day. With contributions from the Wakool River quickly receding, the flow in the Murray at Wakool Junction fell from 27,600 ML/day to 19,100 ML/day this week, and is expected to continue receding over the coming weeks. Dissolved oxygen levels have improved considerably and are currently around 5.8 mg/L.

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Photo 1 – Wetland vegetation in Reedy lagoon (part of the Gunbower Creek system downstream of Torrumbarry Weir) has responded well to recent flooding. (Photo courtesy: Damian McRae)

On the Murrumbidgee River at Balranald, the flow has fallen from around 14,000 ML/day to 10,600 ML/day this week, and at this stage is expected to return to channel capacity in the coming week. Dissolved oxygen levels improved during the week from around 1 mg/L to 4 mg/L. On the Murray downstream of the junction with the Murrumbidgee, dissolved oxygen levels are currently around 4.7 mg/L at Boundary Bend.

Downstream on the Murray at Euston, the flow has fallen to 34,200 ML/day and is expected to continue receding into the New Year. The weir was reinstated during the week and is currently being managed around 20 cm above the normal full supply level (FSL) of 47.6 m AHD in order to hold additional water to help refill Mildura weir once it is reinstated. Dissolved oxygen levels at Euston have started to improve, increasing from around 1 mg/L to 4 mg/L earlier this week.

The river level is falling rapidly at Mildura Weir, and is currently 33.88 m AHD. The weir will be reinstalled starting this coming Friday (16 December). The water level has to fall around 1.7m below the FSL of 34.4 m AHD before the lock can be closed. Once the lock has been closed, installation of the trestles can commence. The water level at Mildura is falling around 30 cm/day, so depending on how long it takes to get the trestles in place (this is expected to be from 2-5 days, depending on the accumulated sediment and debris), the water level will fall further below the FSL before the weir is refilled. See the attached media release for further information.

During the week, the flow at Wentworth fell below the minor flood level, and is currently 65,600 ML/day. Work to start reinstating Wentworth Weir commenced on Wednesday 14 December. See the attached media release for further information.

The volume stored in the Menindee Lakes increased by 33 GL this week to 1,578 GL (91% capacity). Inflows to the lakes are receding and the stored volume is expected to peak during the coming week. The release, measured at Weir 32, is currently around 1,850 ML/day (on Thursday 15 December). A portion of this water is environmental water aimed at supporting the growth and dispersal of Murray Cod that have spawned in the Lower Darling River over the past few months - see the media release from WaterNSW and a joint media release from the Commonwealth Environmental Water Office and the NSW government.

At Lake Victoria, the storage volume has increased by 13 GL this week to 672 GL (99% capacity), and is effectively full. A flow of 3,500 ML/day is being maintained through the outlet regulator to

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provide better quality water in Rufus River. These releases are aimed at providing some refuge for native fish from surrounding hypoxic conditions. Despite high volumes of hypoxic water entering Lake Victoria, monitoring across the lake has shown dissolved oxygen levels within the lake have remained relatively high. Dissolved oxygen readings downstream of the outlet of Lake Victoria (start of Rufus River) have remained above 4.5 mg/L over the last few weeks. In contrast, dissolved oxygen concentrations in the Murray upstream of the junction with the Rufus River have been mostly below 1 mg/L during the last month. However, in the last week the dissolved oxygen concentrations in the Murray have improved slightly and are currently around 2.6 mg/L.

The flow to South Australia has slowly receded to around 81,000 ML/day. The flood peak is currently downstream of Loxton and expected to reach Lock 3 by 19 December and Lock 1 by 25 December—see DEWNR’s latest high flow advice.

The 5-day average level in the Lower Lakes is 0.84 m AHD with high barrage releases expected to continue into January 2017.

For media inquiries contact the Media Officer on 02 6279 0141

DAVID DREVERMANExecutive Director, River Management

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Water in Storage Week ending Wednesday 14 Dec 2016

MDBA StoragesFull

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 3 856 471.65 2 984 77% 71 2 913 +11Hume Reservoir 192.00 3 005 191.21 2 848 95% 23 2 825 -34Lake Victoria 27.00 677 26.96 672 99% 100 572 +13Menindee Lakes 1 731* 1 578 91% (480 #) 1 098 +33

Total 9 269 8 082 87% - - 7 408 +22Total Active MDBA Storage 86% ^

Major State StoragesBurrinjuck Reservoir 1 026 976 95% 3 973 -6Blowering Reservoir 1 631 1 573 96% 24 1 549 -13Eildon Reservoir 3 334 2 652 80% 100 2 552 -6

* 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 13 Dec 2016 Storage Active Storage

(GL)Weekly Change

(GL) Diversion (GL) This Week From 1 May 2016

Lake Eucumbene - Total 2 079 -47 Snowy-Murray +26 806Snowy-Murray Component 939 -21 Tooma-Tumut +0 306Target Storage 1 510 Net Diversion 26 500

Murray 1 Release +33 1 179

Major Diversions from Murray and Lower Darling (GL) *New South Wales This Week From 1 July

2016 Victoria This Week From 1 July 2016

Murray Irrig. Ltd (Net) 28.0 272 Yarrawonga Main Channel (net) 6.9 56Wakool Sys Allowance 0.0 0 Torrumbarry System + Nyah (net) 16.4 137Western Murray Irrigation 1.0 6 Sunraysia Pumped Districts 4.7 29Licensed Pumps 5.6 61 Licensed pumps - GMW (Nyah+u/s) 0.5 7Lower Darling 0.1 2 Licensed pumps - LMW 7.5 111TOTAL 34.7 341 TOTAL 36 340

* 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 217.0 *Flow this week 602.3 (86 000 ML/day)Flow so far this month 1,248.0Flow last month 2,169.8

Salinity (EC) (microSiemens/cm at 25o C)Current Average over the last week Average since 1 August 2016

Swan Hill 110 110 150Euston 180 180 -Red Cliffs 200 200 160Merbein - 200 160Burtundy (Darling) 370 360 710Lock 9 210 210 160Lake Victoria 190 230 180Berri 230 240 190Waikerie 340 350 220Morgan 340 360 220Mannum 370 360 230Murray Bridge 370 360 240Milang (Lake Alex.) 330 330 580Poltalloch (Lake Alex.) 380 350 310Meningie (Lake Alb.) 1 810 1 770 1 780

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Goolwa Barrages 300 340 1 400

River Levels and Flows Week ending Wednesday 14 Dec 2016Minor Flood

Stage Gauge Height Flow Trend Average Flow this Week

Average Flow last

WeekRiver Murray (m) local (m) (m AHD) (ML/day) (ML/day) (ML/day)Khancoban - - - 7 130 F 5 860 5 100Jingellic 4.0 2.19 208.71 8 670 F 7 810 7 590Tallandoon ( Mitta Mitta River ) 4.2 1.55 218.44 900 S 980 1 070Heywoods 5.5 2.99 156.62 14 540 R 13 660 17 180Doctors Point 5.5 3.13 151.60 17 040 R 15 870 19 440Albury 4.3 2.12 149.56 - - - -Corowa 4.6 3.18 129.20 15 450 R 15 490 19 920Yarrawonga Weir (d/s) 6.4 2.17 117.21 14 430 S 14 750 14 770Tocumwal 6.4 2.97 106.81 16 220 S 16 870 16 590Torrumbarry Weir (d/s) 7.3 2.48 81.03 7 610 R 7 700 8 930Swan Hill 4.5 1.51 64.43 8 060 F 8 690 11 090Wakool Junction 8.8 5.10 54.22 19 080 F 22 390 33 660Euston Weir (d/s) 9.1 4.61 46.45 34 200 F 43 550 72 540Mildura Weir (d/s) - - 43 720 F 55 680 84 630Wentworth Weir (d/s) 7.3 6.40 31.16 65 570 F 77 050 97 040Rufus Junction - 7.78 24.71 80 990 F 86 040 92 250Blanchetown (Lock 1 d/s) - 4.00 - 71 900 R 67 690 58 410

TributariesKiewa at Bandiana 2.8 1.53 154.76 1 290 R 1 140 1 200Ovens at Wangaratta 11.9 8.41 146.09 1 590 R 1 820 1 720Goulburn at McCoys Bridge 9.0 1.53 92.95 1 020 S 1 040 1 220Edward at Stevens Weir (d/s) 5.5 1.93 81.70 1 900 F 1 950 3 910Edward at Liewah - 3.29 58.67 2 980 F 3 500 4 730Wakool at Stoney Crossing - 2.39 55.89 3 670 F 4 710 8 770Murrumbidgee at Balranald 5.0 5.90 61.86 10 600 F 12 170 16 400Barwon at Mungindi 6.1 3.25 - 170 R 80 240Darling at Bourke 9.0 4.22 - 910 F 1 440 2 830Darling at Burtundy Rocks - 1.20 - 1 490 R 1 140 720

Natural Inflow to Hume 6 950 7 350 (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/sFSL (m AHD) u/s d/s

Yarrawonga 124.90 -0.16 - No. 7 Rufus River 22.10 +3.01 -28.25No. 26 Torrumbarry 86.05 +0.00 - No. 6 Murtho 19.25 +0.81 +3.69No. 15 Euston 47.60 +0.28 - No. 5 Renmark 16.30 +0.71 +3.73No. 11 Mildura 34.40 n/a +3.08 No. 4 Bookpurnong 13.20 +1.53 +4.80No. 10 Wentworth 30.80 +0.46 +3.76 No. 3 Overland Corner 9.80 +1.09 +4.70No. 9 Kulnine 27.40 n/a +3.53 No. 2 Waikerie 6.10 +2.03 +4.83No. 8 Wangumma 24.60 n/a -31.10 No. 1 Blanchetown 3.20 +1.10 +3.25

Lower Lakes FSL = 0.75 m AHDLake Alexandrina average level for the past 5 days (m AHD) 0.84

Barrages Fishways at Barrages

OpeningsLevel (m AHD) No. Open Rock Ramp

Vertical Slot 1 Vertical Slot 2

Dual Vertical

SlotsGoolwa 128 openings 0.78 25 - Open Open -Mundoo 26 openings 0.79 All closed - - - OpenHunters Creek - - - - Open - -Boundary Creek 6 openings - All closed - Open - -Ewe Island 111 gates - All closed - - - OpenTauwitchere 322 gates 0.81 130 Open Open Open -

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

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Week ending Wednesday 14 Dec 2016

State Allocations (as at 14 Dec 2016)NSW - Murray Valley Victorian - Murray Valley

High security 100%General security 100%

High reliability 100%Low reliability 0%

NSW – Murrumbidgee Valley Victorian - Goulburn ValleyHigh security 100%General security 100%

High reliability 100%Low reliability 0%

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

High security 100%

NSW : http://www.water.nsw.gov.au/water-management/water-availabilityVIC : http://nvrm.net.au/seasonal-determinations/currentSA : http://www.environment.sa.gov.au/managing-natural-resources/river-murray

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Weirs near Mildura back in operation to manage weir pools

Weirs on the River Murray in Victoria and New South Wales are being reinstated during December as the floods pass downstream into South Australia.

The Murray–Darling Basin Authority (MDBA) head of River Management, David Dreverman, said it was important to return the amenity of well managed weir pools.

“We are grateful to local communities for their patience while work is underway to have the locks and weirs functioning again for the summer. This infrastructure brings great economic benefit to many communities by enabling navigation the length of the river, tourism and recreation, and access to irrigation water,” Mr Dreverman said. “Re-installing the weirs is safe and relatively quick, thanks to significant investment by basin governments over the last decade to improve flood operations,” Mr Dreverman said. The MDBA had removed the weirs in October to safely allow flood waters to pass unencumbered.

The Euston weir (lock 15) was successfully reinstated last week.

Work at the Wentworth weir (lock 10) will be starting on Wednesday 14 December. Passage through the lock will be unavailable for up to one week while staff are reinstating the weir, however passage by appointment may be possible by contacting lock staff on 0350273190.

Mr Dreverman said work to reinstate the Mildura weir (lock 11) was expected to start on Friday 16 December, given the current rate at which the river was falling.

“This work has been brought forward by a few days in response to irrigator feedback, to limit the period in which pumping from the river might be impacted,” Mr Dreverman said.

“The process of reinstating the Mildura weir is likely to take between two and five days, and it would be about another seven days before the weir pool returns to full supply level. Until then, lower levels might temporarily affect some people’s access to water or require adjustments to boat moorings.

“The last opportunity for river traffic to pass the Mildura weir will be on Thursday 15 December, before Lock 11 re-opens to traffic, which is expected to be one week after the weir is reinstated. Navigation with care upstream and downstream of the lock is still possible, however we advise water skiers and other river users to be wary of logs and obstacles close to the surface. “Timing the reinstatement of the weirs depends on how quickly the river recedes. As it happens, we expect flows at Mildura to fall to a critical point that coincides with the Christmas period.

“Waiting until after Christmas would have risked low flows at Mildura impacting on the local tourism industry and irrigators’ access to water. To take action earlier, when river levels were higher, would have risked the integrity of the weir structure and safety of the operators.

Management of the weirs is coordinated by the MDBA in cooperation with Goulburn-Murray Water, WaterNSW and SA Water. For more information about River Murray operations, see the Weekly Report at www.mdba.gov.au/river-information/weekly-reports

ENDFor more information, contact the MDBA Media office at media@mdba.gov.au or 02 6279 0141

MEDIA RELEASE UPDATED 13 December 2016

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