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River Murray Weekly Report For the week ending Wednesday, 4 September 2019

Trim Ref: D19/40890

Rainfall and inflows Rainfall in the southern Murray-Darling Basin was quite limited this week, and mostly fell across the southern ranges and central Victoria (Map 1). Highest totals included 23 mm at Mt Buller AWS in Victoria’s upper northeast and 16 mm at Lake Eildon. Some light rain was recorded in the northern Basin.

Map 1 - Rainfall totals for week ending 4th September (Source: Bureau of Meteorology)

Flows in the upper tributaries of the River Murray System continued to gradually recede until mid-week, after which flows increased slightly in response to a small rainfall event. For 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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August 2019 summary The BoM reports an area-average rainfall of 11.0 mm for the Murray-Darling Basin in August 2019. This is 71% below the Basin’s long-term average for August and sits as the 8th lowest on record and the lowest since 2006 for this month (Map 2). Large areas of NSW received very much below average rainfall and in eastern South Australia and central-west NSW, scattered areas of the Basin received lowest on record rainfall this August.

River Murray system inflows for August 2019 remained quite low, reaching about 530 GL which is less than half of the long-term median inflow for August of 1,240 GL.

Map 2 – Murray-Darling Basin rainfall deciles for August 2019 (Source: Bureau of Meteorology)

The BoM reports that the mean temperature in August 2019 for Australia was warmer than average. Maximum temperatures were near average for the southern Murray-Darling Basin, whilst minimum temperatures were well below average for large areas of NSW, South Australia and northern Victoria (Map 3 & 4) reflecting the generally clear and dry conditions experienced for much of the month.

Map 3 & 4 – Maximum and minimum temperature deciles for July 2019 (Source: Bureau of Meteorology)

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River operations

River operations The MDBA total active storage remained fairly steady this week around 3,953 GL (47% capacity).

At Dartmouth Reservoir, the storage decreased by 13 GL to 2,287 GL (59% capacity). Releases are continuing from Dartmouth to transfer water to Hume to support expected system demands in the months ahead.

The release from Dartmouth, measured at Colemans, is currently 5,600 ML/day, which is the expected peak rate for September. Releases during this month are expected to vary between around 2,800 ML/day and 5,600 ML/day. Over the coming months, releases will continue to be varied in a manner that will transfer the required volume to Hume, whilst seeking to minimise erosion along the lower Mitta Mitta River and provide for power generation.

At Hume Reservoir, the storage decreased by 8 GL to 1,300 GL (43% capacity). WaterNSW are currently undertaking scheduled maintenance works at Hume Dam to refurbish the irrigation penstocks and their emergency closure gates. Works are expected to be completed by the end of 2021. More information regarding these works and access across the dam wall can be found on the WaterNSW website.

The release from Hume Dam increased midweek to 13,000 ML/day and has since reduced to the current release near 11,000 ML/day. Without significant rainfall, releases are likely to remain around this rate during September to meet higher demands including environmental orders.

Downstream of Hume, tributary inflows from the Kiewa at Bandiana have averaged around 1,700 ML/day over the past week. In the Ovens catchment, flow at Wangaratta averaged 3,300 ML/day. With some rainfall forecast over the Ovens catchment, the flow at Wangaratta may increase during the coming week.

Downstream at Lake Mulwala the pool level is currently 124.77 m AHD and is expected to remain within the normal operating range of 124.6 to 124.9 m AHD in the coming week. Diversions to the Mulwala Canal and Yarrawonga Main Channel (YMC) both increased this week to 1,000 ML/day.

The release downstream of Yarrawonga Weir has been increasing from 1 September at a rate of 1,000 ML/day as planned spring environmental watering actions commence. The downstream release is currently 13,500 ML/day and will reach a maximum of 15,000 ML/day early next week.

This flow is being delivered on behalf of environmental water holders who have identified inundation of the Barmah-Millewa Forest as a key watering action for this year. The aim of this flow rate is to build on the benefits achieved from delivering environmental water during August, which inundated parts of the Barmah-Millewa Forest, and improving access to food and habitat for native fish. Return flows from this event will be coordinated with a planned environmental pulse from the Goulburn River providing ecological benefits along the River Murray to the Coorong in South Australia. Updates on environmental watering actions during spring 2019 are available from the Commonwealth Environmental Water Office website. For more information on how environmental water is helping to improve the health of rivers in the Basin see the NSW Department of Planning, Industry and Environment website and the latest fact sheet and update from the Commonwealth Environmental Water Office.

Flows through the Edward and Gulpa offtakes are currently near 1,530 and 700 ML/day respectively. Over the last week the flow at Gulpa offtake was gradually increased from 250 ML/day to 700 ML/day to deliver environmental water to Gulpa wetlands. The action aims to provide optimal nesting habitat over October, November and into December for the endangered Australasian Bittern.

• Flows downstream of Yarrawonga to reach 15,000 ML/day in the coming week as environmental water deliveries continue.

• Delivery of environmental water to Koondrook-Perricoota Forest recently commenced. • Weir pool levels to rise at Locks 15, 8 & 7.

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Further downstream on the Edward River at Toonalook, the flow is being boosted by water returning from the Millewa Forest. Yallakool and Colligen Creeks are currently receiving environmental water to provide base flows for native fish. These deliveries are expected to reduce over the coming week. At Stevens Weir the release is currently near 2,100 ML/day.

On the Goulburn River the flow has averaged around 1,200 ML/day. Planning is currently underway to deliver a spring flow pulse through the Goulburn system, most likely from mid-September. Further updates will be provided in the coming weeks.

The current Goulburn IVT balance is around 225 GL. More information regarding current opportunities for allocation trade between the Goulburn and Murray valleys is available at the Victorian water register website. In August, the Victorian Minister for Water announced changes to the Goulburn system trade rules and flagged revisions to the summer operating regime for the Goulburn River. More information on these changes will be provided in coming months.

Downstream at Torrumbarry weir pool, diversions to Koondrook-Perricoota Forest commenced in late August (Photo 1 and 2). Koondrook-Perricoota Forest was last inundated during 2016 following extensive natural flooding. However dry conditions since then have seen the health of the forest and wetlands deteriorate and the MDBA’s ‘Basin Environmental Watering Priorities 2019-20’ has identified Koondrook-Perricoota Forest as a priority site to receive water this year. A flow of around 500 ML/day is planned for delivery through September and October, with a total volume of around 30 GL expected to be delivered. This is expected to inundate approximately 4,500 ha, or just over 10% of the forest.

Photo 1 & 2: Satellite imagery of Koondrook-Perricoota Forest (left) (Image courtesy of Sentinel Hub) and the extent (indicated in the arrow) of environmental watering action along the Little Burrumbury Creek (right) (photo courtesy Forestry Corporation)

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The diversion to National Channel remained around 2,000 ML/day this week to refill the Torrumbarry Irrigation Network and Kow Swamp in preparation for the 2019-20 irrigation season. Water is also being used to maintain base flows through Gunbower Creek to benefit native fish. Much of this flow is returning to the River Murray at Barham via Koondrook spillway. The additional loss attributed to maintaining this higher flow in the creek is debited from Victorian held environmental entitlements.

The Torrumbarry Weir pool is currently at Full Supply Level (FSL) (86.05 m AHD). Downstream of Torrumbarry Weir, the release averaged near 5,800 ML/day. Releases are expected to start rising during the coming week as planned environmental actions boost River Murray flows. During September and October, a planned environmental action in the Goulburn, combined with the Murray action, will see flow rates increase more significantly.

Inflow from the Murrumbidgee River, measured at Balranald, is currently around the September end of system target of 1,330 ML/day. The Murrumbidgee IVT balance is currently 100 GL, which is the upper limit, meaning trade from the Murrumbidgee to the Murray is closed. Trade will remain closed until the account reduces below 85 GL. This could occur from trade from the Murray back to the Murrumbidgee, and/or from IVT deliveries from the Murrumbidgee to the Murray in coming months.

In response to this change, MDBA is revising its operations planning to account for the increased water available to be delivered from the Murrumbidgee IVT account.

At Euston, the weir pool level is currently 20 cm above FSL. The pool level is planned to gradually rise to around 50 to 60 cm above FSL in the coming weeks 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. The downstream release is currently around 9,700 ML/day and is expected to recede over the coming week. Downstream of Euston Weir, around 140 ML/day of environmental water is being pumped into Lake Kramen within the Hattah Lakes system.

The Menindee Lakes storage is approximately 14 GL (less than 1% capacity). WaterNSW continues to manage the Menindee Lakes in accordance with the Lower Darling Annual Operations Plan. WaterNSW has advised that releases at Weir 32 are only planned to recommence when significant inflows are received into the Menindee Lakes. Inflows are currently zero and no significant inflows are expected in the near future.

As a result of the widespread drought conditions in NSW, extensive water restrictions are likely to remain in place. More information on drought management activities in NSW can be found on the NSW Government website - Drought Hub.

On the Murray at Wentworth Weir, the pool level is currently targeting 10 cm above FSL to assist pumpers in the upper reaches of the Darling River arm of the weir pool whilst there is no inflow from the Darling River. The downstream release averaged near 9,100 ML/day.

At Locks 8 and 7, the pool levels are targeting around 10 cm above FSL during August as part of the weir pool variability program. During September, these pool levels are planned to be raised further to 85 cm above FSL at Lock 8 and 55 cm above FSL at Lock 7. Whilst the pool levels are surcharged above FSL, regulators have been opened to allow water to flow through the upper reaches of Potterwalkagee Creek (around Lock 8) and Lindsay River (around Lock 7) and reconnect with the River Murray for the benefit of native fish.

At Lake Victoria, water storage increased by 20 GL to 560 GL (83% capacity). The level is expected to continue to increase over the coming week or two.

The flow to South Australia is around 5,500 ML/day. This flow consists of reduced August entitlement flow and environmental water originally released from Hume and Eildon Dams. Due to low water resource availability in the Murray-Darling Basin, South Australia is currently receiving a reduced monthly base Entitlement flow. During September, the monthly volume has been reduced from the normal 135 GL to 105 GL. For more information see the South Australian Department for Environment and Water’s latest River Murray flow report.

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Photo 3: Dredges in operation at the Murray Mouth (Photo courtesy of MDBA)

The Lower Lakes 5-day average water level remained near 0.78 m AHD. Approximately 17 GL was released through the barrages over the week, supported by the delivery of environmental water in recent months. These barrage releases provide environmental cues and connection to support the movement of several migratory fish species, including the short-headed lamprey which can travel large distances from the Southern Ocean to their spawning grounds in upstream reaches of the River Murray System.

For media inquiries contact the Media Officer on 02 6279 0141

Angus Paton Acting Executive Director, River Management

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Water in Storage Week ending Wednesday 04 Sep 2019

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 3 856 458.22 2 287 59% 71 2 216 -13 Hume Reservoir 192.00 3 005 181.40 1 300 43% 23 1 277 -8 Lake Victoria 27.00 677 26.01 560 83% 100 460 +20 Menindee Lakes 1 731* 14 1% (- -) # 0 -0 Total 9 269 4 161 45% - - 3 953 -1 Total Active MDBA Storage 47% ^ Major State Storages

Burrinjuck Reservoir 1 026 338 33% 3 335 +2 Blowering Reservoir 1 631 n/a n/a 24 n/a n/a Eildon Reservoir 3 334 1 517 45% 100 1 417 +27

* 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 03 Sep 2019 Storage Active Storage (GL) Weekly Change (GL) Diversion (GL) This Week From 1 May 2019 Lake Eucumbene - Total 790 n/a Snowy-Murray +6 225 Snowy-Murray Component 306 n/a Tooma-Tumut +6 114 Target Storage 1 240 Net Diversion 0 111 Murray 1 Release +10 319

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) 7.0 41 Yarrawonga Main Channel (net) 5.6 11 Wakool Sys Allowance 1.6 11 Torrumbarry System + Nyah (net) 11.4 32 Western Murray Irrigation 0.3 2 Sunraysia Pumped Districts 1.1 5 Licensed Pumps 1.5 7 Licensed pumps - GMW (Nyah+u/s) 1 1 Lower Darling 0.0 0 Licensed pumps - LMW 4.6 13 TOTAL 10.4 61 TOTAL 23.7 62

* 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 135.0 * Flow this week 41.4 (5 900 ML/day) Flow so far this month 23.5 Flow last month 172.0

Salinity (EC) (microSiemens/cm at 25o C) Current Average over the last week Average since 1 August 2019 Swan Hill 70 70 80 Euston - - - Red Cliffs 60 60 70 Merbein 100 110 100 Burtundy (Darling) 1 260 1 260 1 210 Lock 9 110 110 90 Lake Victoria 110 110 120 Berri 160 160 160 Waikerie 240 230 240 Morgan 240 250 250 Mannum 320 330 330 Murray Bridge 360 370 370 Milang (Lake Alex.) 890 900 860 Poltalloch (Lake Alex.) 820 820 820 Meningie (Lake Alb.) 1 690 1 710 1 700 Goolwa Barrages 1 800 1 980 3 290

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River Levels and Flows Week ending Wednesday 04 Sep 2019

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 - - - 1 460 F 2 610 3 320 Jingellic 4.0 1.64 208.16 4 030 F 5 220 6 510 Tallandoon ( Mitta Mitta River ) 4.2 2.82 219.71 6 100 S 4 550 5 240 Heywoods 5.5 2.92 156.55 12 130 F 11 280 3 790 Doctors Point 5.5 2.88 151.35 13 530 F 12 750 5 990 Albury 4.3 1.87 149.31 - - - - Corowa 4.6 2.84 128.86 13 440 R 10 310 5 550 Yarrawonga Weir (d/s) 6.4 2.12 117.16 13 660 R 11 450 10 370 Tocumwal 6.4 2.53 106.37 12 550 R 11 220 10 080 Torrumbarry Weir (d/s) 7.3 2.03 80.57 5 640 F 5 740 6 980 Swan Hill 4.5 1.21 64.13 6 000 F 6 270 8 080 Wakool Junction 8.8 3.11 52.23 8 600 F 9 290 10 260 Euston Weir (d/s) 9.1 1.72 43.56 9 640 S 10 610 10 650 Mildura Weir (d/s) - - 10 660 F 10 750 9 960 Wentworth Weir (d/s) 7.3 3.11 27.87 9 110 S 9 090 8 660 Rufus Junction - 3.18 20.11 4 870 F 5 220 2 800 Blanchetown (Lock 1 d/s) - 0.75 - 4 660 F 4 240 2 810 Tributaries Kiewa at Bandiana 2.8 1.79 155.02 1 640 F 1 720 2 060 Ovens at Wangaratta 11.9 8.90 146.58 2 940 S 3 350 5 650 Goulburn at McCoys Bridge 9.0 1.66 93.08 1 260 R 1 170 1 650 Edward at Stevens Weir (d/s) 5.5 2.08 81.85 2 110 F 1 790 1 810 Edward at Liewah - 2.38 57.76 1 710 F 1 880 1 960 Wakool at Stoney Crossing - 1.51 55.00 670 R 610 440 Murrumbidgee at Balranald 5.0 1.74 57.70 1 310 R 1 260 1 110 Barwon at Mungindi 6.1 2.60 - 0 F 0 0 Darling at Bourke 9.0 2.86 - 0 F 0 0 Darling at Burtundy Rocks - 0.49 - 0 F 0 0 Natural Inflow to Hume 8 330 11 060

(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 -0.13 - No. 7 Rufus River 22.10 +0.12 +0.86 No. 26 Torrumbarry 86.05 +0.00 - No. 6 Murtho 19.25 -0.00 +0.06 No. 15 Euston 47.60 +0.22 - No. 5 Renmark 16.30 +0.01 +0.16 No. 11 Mildura 34.40 +0.01 +0.36 No. 4 Bookpurnong 13.20 +0.04 +0.59 No. 10 Wentworth 30.80 +0.10 +0.47 No. 3 Overland Corner 9.80 +0.01 +0.64 No. 9 Kulnine 27.40 +0.03 +0.13 No. 2 Waikerie 6.10 +0.51 +0.15 No. 8 Wangumma 24.60 +0.10 +0.21 No. 1 Blanchetown 3.20 +0.01 +0.00

Lower Lakes FSL = 0.75 m AHD Lake Alexandrina average level for the past 5 days (m AHD) 0.78

Barrages Fishways at Barrages Openings Level (m AHD) No. Open Rock Ramp Vertical Slot 1 Vertical Slot 2 Dual Vertical Slots Goolwa 128 openings 0.81 2 - Open Open - Mundoo 26 openings 0.77 1 - - - Open Hunters Creek - - - - Open - - Boundary Creek 6 openings - 1 - Open - - Ewe Island 111 gates - All closed - - - Open Tauwitchere 322 gates 0.77 2 Open Open Open - AHD = Level relative to Australian Height Datum, i.e. height above sea level

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Week ending Wednesday 04 Sep 2019

State Allocations (as at 04 Sep 2019)

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

High reliability 33% Low reliability 0%

NSW – Murrumbidgee Valley

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

High reliability 37% Low reliability 0%

NSW - Lower Darling

South Australia – Murray Valley High security 30% General security 0%

High security 74%

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