Rainfall and inflows - Murray-Darling Basin Authority · Web view2020/04/29  · Rainfall was widespread across the southern Murray-Darling Basin for the week ending 29th April 2020

River Murray Weekly ReportFor the week ending Wednesday, 29 April 2020

Trim Ref: D20/14732

Rainfall and inflowsRainfall was widespread across the southern Murray-Darling Basin for the week ending 29th April 2020 (Map 1). 50 to 100 mm was recorded across much of the upper Murray catchment in both Victoria and NSW. In Victoria’s north east catchments, 92 mm was recorded at Mt Buffalo on the Buffalo River, which feeds into the Ovens River, and 90 mm fell at Mongans Bridge on the Kiewa River. The Ovens and Kiewa Rivers are tributaries that flow into the River Murray downstream of Hume Reservoir.

In South Australia, rainfall totals of 25 to 50 mm were recorded across most of the Murray catchments.

Map 1 – Rainfall across the Murray-Darling Basin for the week ending 29 April 2020. Source: Bureau of Meteorology.

On Thursday 30th April 2020, significant rainfall continued to be recorded across the upper Murray catchments (Map 2 – across the page). In Victoria’s north east, a further 89 mm fell at Mt Buffalo on the Buffalo River and 117 mm was recorded at Mt Buller AWS, in the upstream reaches of the King River, both of which are upstream tributaries of the Ovens River. On the Kiewa River, Mongans Bridge received another 72 mm.

In the 8-day rainfall outlook, the Bureau of Meteorology is forecasting rainfall to continue over the coming days, with totals of up to 50 mm possible in the upper Murray catchments.

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The Bureau of Meteorology have issued flood warnings for Victoria for the River Murray upstream of Hume and the Ovens, King and Kiewa Rivers.

In the River Murray upstream of Hume, Biggara reached minor flood level near 8,700 ML/day and has since reduced to 7,000 ML/day. Further downstream at Jingellic, flow is near 12,500 ML/day. In the Kiewa River, the inflow to the River Murray, measured at Bandiana , is currently rising and is near 3,500 ML/day. However, further upstream on the Kiewa River at Mongans Bridge flow peaked around 14,000 ML/day, which is moderate flood level.

In the Ovens River, the inflow to the River Murray, measured at Peechelba , is rising and is currently near 1,400 ML/day. Further upstream on the Ovens River, the flow at Rocky Point has reached 15,000 ML/day. The King River, which flows into the Ovens River upstream of Wangaratta reached 15,000 ML/day at Cheshunt.

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 at Bureau of Meteorology’s (BoM) website and in the Murray River Basin daily river report at the WaterNSW website.

Map 2 – Rainfall across the Murray-Darling Basin for Thursday, 30 April 2020. Source: Bureau of Meteorology.

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Photo 1 – High flows after rainfall on the Kiewa River near Ryders Bridge (photo: Hugo Bowman, MDBA)

River operations

River operations and the COVID-19 virusThe MDBA is continuing to work effectively 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.

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 also considered non-essential activity. 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.

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Significant rainfall resulting in minor to moderate flood levels in parts of the upper Murray Releases downstream of Yarrawonga Weir to increase in response to forecast inflows from

Ovens and Kiewa Rivers following rain. Wentworth Weir pool raised back to Full Supply Level (FSL) Higher flows from the lower Darling River passing through the lower Murray River

River Murray Weekly Report

Water quality impactsBushfire 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.

Risks to water quality remain 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.

There are currently no red alerts for blue-green algae in the River Murray system. However, there are a number of ambers alerts which remain current along the river. In particular, Goulburn-Murray Water advises a high cautionary warning remains current for Yarrawonga Weir with the sampling next scheduled for early May 2020. 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 operationsOver the past week, MDBA total active storage (Dartmouth, Hume and Lake Victoria) increased by 35 GL to 2,290 GL (27% capacity). Storage increases as a result of the current rainfall will be captured in next week’s report.

At Dartmouth Reservoir, the storage increased by 4 GL to 1,818 GL (47% capacity). The release from Dartmouth is targeting the minimum operating flow, measured at Colemans, of 200 ML/day.

At Hume Reservoir, the storage increased by 6 GL to 396 GL (13% capacity). Due to the forecast tributary inflows downstream of Hume, the release from Hume was gradually reduced from 4,000 ML/day to the minimum release of 600 ML/day. The release is expected to remain at the minimum release for the coming week.

Photo 2 – River Murray at Wodonga with low flows ahead of the recent rainfall event (photo: Alisha Caldwell, MDBA)

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At Lake Mulwala, the pool level is currently 124.86 m AHD, which is within the normal operating range between 124.6 and 124.9 m AHD. With rainfall falling across the irrigation districts, the diversion to Yarrawonga Main Channel and Mulwala Canal have both reduced to around 150 ML/day.

The release from Yarrawonga Weir has increased this week from 4,500 ML/day to near 9,000 ML/day. The release has been increased to maintain the upstream weir pool level below 124.9 m AHD. The release is likely to increase further in the coming days as the flows from the Ovens and Kiewa catchments arrive. Based on current streamflow forecasts, it is expected that releases will increase above 10,000 ML/day, and therefore will require the opening of the Barmah-Forest regulators. This is normal operational practice in light of these higher natural tributary inflows.

If no further rainfall occurs, the release downstream of Yarrawonga Weir will be reduced back to low levels as soon as possible as system requirements downstream continue to ease. Reducing the 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 decreased slightly to near 820 ML/day as flow in the River Murray have eased. Flow through the Gulpa Creek offtake remained around 230 ML/day. Downstream along the Edward River, diversions through the Wakool offtake regulator averaged 25 ML/day, 220 ML/day through Yallakool Creek offtake and 180 ML/day into Colligen Creek. At Stevens Weir, the downstream flow remained around 650 ML/day before increasing to 840 ML/day with local rainfall.

Inflow from the Broken Creek, measured at Rice’s Weir, rose to the current rate around 305 ML/day with local rainfall. Without rain, a rate of around 180 ML/day is being targeted the majority of which is water for the environment.

In the Goulburn River the flow, measured at McCoys Bridge, averaged 560 ML/day over the week. It is anticipated the flow will increase to 940 ML/day in the coming days. This target flow will be mostly water for the environment delivered on behalf of the Victorian Environmental Water Holder. Inflow from the Goulburn River may also be influenced by rainfall, as small rises upstream of McCoys Bridge around Shepparton have been observed following rain.

Delivery of Goulburn Valley IVT is not currently required to meet Murray system demands. 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 reduced this week from 2,000 ML/day to 1,000 ML/day as irrigation demands reduced. The Torrumbarry Weir pool remains at the Full Supply Level (FSL) of 86.05 m AHD. Flow downstream of Torrumbarry Weir is currently near 3,700 ML/day. Flow downstream of the Weir may vary over the coming week in response to rainfall, inflows from Victorian tributaries and releases from Yarrawonga Weir.

Inflow from the Murrumbidgee River, measured at Balranald , averaged 220 ML/day this week. The Murrumbidgee IVT balance is near 20 GL and trade into and out of the valley is open.

At Euston, the weir pool level is now 30 cm below FSL and will vary within the range of 20-30 cm below FSL over the 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 eased from around 7,300 ML/day to 5,470 ML/day and is likely to continue to decrease over this coming week.

This week the Menindee Lakes storage increased by 14 GL to 319 GL (18% capacity). WaterNSW has been providing regular updates on the streamflow response in the Barwon-Darling system and currently forecasts a volume in the order of 470 to 510 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 moving water from Lake Wetherell and Lake Tandure (combined storage of 175 GL)

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to Lake Pamamaroo (now storing 142 GL) to maximise the storage efficiency in the lakes. Flow through the Pamamaroo inlet regulator is currently 4,000 ML/day.

The release from Weir 32 is targeting 300 ML/day, which is achieved by a release of 320 ML/day from Lake Pamamaroo. WaterNSW will reduce the release at Weir 32 to target 200 ML/day in May. A small release of 20 ML/day is being made from Lake Wetherell. More information about inflows and releases from the Menindee Lakes can be found here. Despite recent rainfall and streamflow responses, 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 pool level was raised back to the current level near FSL this week. The Wentworth Weir pool level was lowered to help assist the passage of any poor-quality water arriving from the lower Darling. With salinity levels in the Darling arm of the weir pool reducing and inflows from the Darling falling away, the weir pool has been raised again. River users are advised to adjust their activities, pumps and moorings to accommodate the changes in weir pool level. Daily updates on water quality and flows along the River Murray can be found here. The downstream release has reduced gradually over the week from 8,700 ML/day to the current release of 6,000 ML/day. The release will continue to fall away over the coming week.

At Lake Victoria, the storage volume increased by 14 GL to 270 GL (40% capacity).

The flow to South Australia averaged around 4,400 ML/day and will remain around this rate for the coming week. This flow comprises the delivery of South Australia’s Monthly Entitlement, trade and environmental water delivery, including environmental water from the recession of the Goulburn River following the local rain event at the start of April. 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. 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 REYNOLDSExecutive Director, River Management

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Water in Storage Week ending Wednesday 29 Apr 2020

MDBA StoragesFull

Supply Level

Full Supply Volume

Current Storage Level

Current Storage Dead

StorageActive

Storage

Change in Total Storage for the

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

Dartmouth Reservoir 486.00 3 856 447.72 1 818 47% 71 1 747 +4Hume Reservoir 192.00 3 005 172.13 396 13% 23 373 +6Lake Victoria 27.00 677 23.25 270 40% 100 170 +11Menindee Lakes   1 731*   319 18% (- -) # 0 +14Total   9 269   2 803 27% - - 2 290 +35Total Active MDBA Storage             27% ^  

Major State StoragesBurrinjuck Reservoir   1 026   387 38% 3 384 +1Blowering Reservoir   1 631   777 48% 24 753 -1Eildon Reservoir   3 334   1 213 36% 100 1 113 +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 28 Apr 2020

Storage Active Storage (GL) Weekly Change (GL) Diversion (GL) This Week From 1 May 2019

Lake Eucumbene - Total 795 n/a Snowy-Murray +9 439Snowy-Murray Component 479 n/a Tooma-Tumut +5 217Target Storage 1 340   Net Diversion 3 222

     Murray 1 Release +12 628

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) 2.9 138 Yarrawonga Main Channel (net) 2.6 125Wakool Sys Allowance 1.2 53 Torrumbarry System + Nyah (net) 0 273Western Murray Irrigation 0.2 23 Sunraysia Pumped Districts 1.3 106

Licensed Pumps n/a 129Licensed pumps - GMW (Nyah+u/s) n/a 24

Lower Darling n/a 1 Licensed pumps - LMW n/a 386TOTAL 4.3 344 TOTAL 3.9 914

* 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 less than normal Entitlement for this month. It includes a reduced monthly Entitlement plus the delivery of environmental and traded water.

Entitlement this month 135.0 *  Flow this week 29.3 (4 200 ML/day)Flow so far this month 116.4Flow last month 171.6

Salinity (EC) (microSiemens/cm at 25o C)

  Current Average over the last week Average since 1 August 2019

Swan Hill 90 90 70Euston - - -Red Cliffs - - 50Merbein 100 100 90Burtundy (Darling) 240 240 920Lock 9 140 120 100Lake Victoria 140 140 120Berri 180 180 150Waikerie 220 220 210Morgan 230 230 220Mannum 250 250 260

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Murray Bridge 280 280 280Milang (Lake Alex.) 960 970 880Poltalloch (Lake Alex.) 770 780 820Meningie (Lake Alb.) 1 720 1 800 1 790Goolwa Barrages 7 420 5 140 2 320

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River Levels and Flows Week ending Wednesday 29 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 - - - 3 070 F 2 870 1 720Jingellic 4.0 - - 5 040 F 3 980 2 950Tallandoon ( Mitta Mitta River ) 4.2 1.50 218.39 760 R 610 540Heywoods 5.5 1.53 155.16 630 F 2 990 4 990Doctors Point 5.5 1.70 150.17 2 170 F 3 930 6 480Albury 4.3 0.88 148.32 - - - -Corowa 4.6 0.96 126.98 2 920 F 4 570 5 500Yarrawonga Weir (d/s) 6.4 0.89 115.93 4 990 R 4 790 5 460Tocumwal 6.4 1.33 105.17 4 210 R 4 490 5 150Torrumbarry Weir (d/s) 7.3 1.48 80.03 3 730 R 3 140 4 070Swan Hill 4.5 0.87 63.79 3 710 R 3 770 5 710Wakool Junction 8.8 2.21 51.33 4 760 F 5 320 7 090Euston Weir (d/s) 9.1 1.11 42.95 5 470 F 6 120 7 570Mildura Weir (d/s)   - - 6 140 F 6 860 6 600Wentworth Weir (d/s) 7.3 2.85 27.61 6 060 F 7 170 8 230Rufus Junction - 3.02 19.95 4 030 R 3 800 3 290Blanchetown (Lock 1 d/s) - 0.40 - 3 170 F 2 330 2 150               Tributaries              Kiewa at Bandiana 2.8 1.60 154.83 1 330 F 910 840Ovens at Wangaratta 11.9 8.30 145.98 1 340 F 1 150 1 010Goulburn at McCoys Bridge 9.0 1.27 92.69 600 R 560 1 030Edward at Stevens Weir (d/s) 5.5 1.12 80.89 840 F 680 690Edward at Liewah - 1.50 56.88 860 F 950 1 000Wakool at Stoney Crossing - 1.39 54.88 410 S 420 430Murrumbidgee at Balranald 5.0 0.48 56.44 210 R 230 330Barwon at Mungindi 6.1 3.35 - 430 F 460 340Darling at Bourke 9.0 5.73 - 12 230 R 10 290 5 110Darling at Burtundy Rocks - 0.84 - 460 F 880 2 360               Natural Inflow to Hume           2 870 2 370

(i.e. Pre Dartmouth & Snowy Mountains scheme)

Weirs and Locks Pool levels above or below Full Supply Level (FSL)

MurrayFSL (m AHD) u/s d/s   FSL (m AHD) u/s d/s

Yarrawonga 124.90 -0.04 - No. 7 Rufus River 22.10 -0.04 +0.71No. 26 Torrumbarry 86.05 -0.00 - No. 6 Murtho 19.25 +0.05 +0.03No. 15 Euston 47.60 -0.28 - No. 5 Renmark 16.30 +0.04 +0.22No. 11 Mildura 34.40 -0.02 +0.07 No. 4 Bookpurnong 13.20 +0.14 +0.51

No. 10 Wentworth 30.80 -0.02 +0.21No. 3 Overland Corner 9.80 +0.17 +0.32

No. 9 Kulnine 27.40 -0.03 -0.94 No. 2 Waikerie 6.10 +0.19 +0.20No. 8 Wangumma 24.60 -0.95 -0.01 No. 1 Blanchetown 3.20 +0.13 -0.35

Lower Lakes FSL = 0.75 m AHDLake Alexandrina average level for the past 5 days (m AHD) 0.52

Barrages Fishways at Barrages

  Openings Level (m AHD)No. Open Rock Ramp Vertical Slot 1

Vertical Slot 2 Dual Vertical Slots

Goolwa 128 openings 0.42All

closed - Closed Open -

Mundoo 26 openings 0.35All

closed - - - OpenHunters Creek - - - - Open - -

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Boundary Creek 6 openings -

All closed - Open - -

Ewe Island 111 gates -All

closed - - - OpenTauwitchere 322 gates 0.53 1 Open Open Open -

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

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Week ending Wednesday 29 Apr 2020

State Allocations (as at 29 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 ValleyHigh security 95%General security 6%

High reliability 80%Low reliability 0%

NSW - Lower Darling South Australia – Murray ValleyHigh security 100%General security 0%

High security 100%

NSW : https://www.industry.nsw.gov.au/water/allocations-availability/allocations/summaryVIC : http://nvrm.net.au/seasonal-determinations/currentSA : http://www.environment.sa.gov.au/managing-natural-resources/river-murray

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