River Murray weekly report
For the week ending Wednesday, 11th May2018
Trim Ref:D16/16794
Rainfall and inflows
An extensive north-west cloud band streamed across the continent from the Indian Ocean over the weekend bringing rainfall across much of the Murray–Darling Basin. The system was closely followed by a complex and intense low pressure system that crossed the southern Basin bringing strong winds and further showers that were persistent and heaviest about the ranges.The rain has provided much-needed relief from the mostly very dry and warm conditions of recent months, and was one of the Basin’s most widespread rain events for some time.
Rainfall totals between 25 and 50 mm were recorded over most of NSW, large parts of Victoria and some of south-western Queensland; with totals in excess of 50 mm over north-western NSW. Across the south-eastern slopes and ranges totals over 100 mm were common, with considerably higher falls over the peaks. Conditions across south-western and north-western parts of the Basin were comparatively dry (Map 1).
The highest rainfall totals were recorded over the upper Murray and Victorian tributary catchments. Totals in Victoria included 311 mm at Mt Buffalo, 191 mm at Whitlands, 185 mm at Harris Lane, 164mm at Cheshunt, 156 mm at Hunters Hill and 73 mm at Hume Reservoir. Totals in NSW were heaviest over the Snowy Mountains where up to 200 mm was recorded. Further afield, there was 104mm at Burrinjuck Dam and 86 mm at Mt Ginini. In the north-western Basin, rain along the Paroo and Darling River Valleys included 83 mm at Wanaaring, 82 mm at Hungerford and 63 mm at Louth.
Map 1 - Murray-Darling Basin rainfall week ending 11th May 2016 (Source: Bureau of Meteorology)
Flows have increased along the upper System tributaries following the rain, helped bycatchment wetting resulting from rain that fell during the preceding week. Flow peaks at some gauges were higher than any observed during the last 12 months.
On the upper Murray at Bringenbrong, flows increased from around 800 to 12,500 ML/day. This was the highest flow recorded at this gauge since July 2013, but was largely due to airspace management releases from Snowy Hydro following a deluge over the western slopes of the Snowy Mountains. On the upper Mitta Mitta River, the flow at Hinnomunjie bridge briefly reached rates above 8,000 ML/day before receding quickly. The current flow is around 3,000 ML/day. On the Kiewa River, the flow at Mongans Bridge touched the minor flood level (2.4m) for the first time since September 2014, with flows peaking at around 6,000ML/day. The current flow is just under 3,000 ML/day. Downstream at Bandiana, flows are continuing to rise (Figure 1) and the Bureau of Meteorology is warning that river levels may exceed the minor flood level (2.8 m) during the next day or two. On the Ovens River, the flow at Rocky Point climbed from around 200 ML/day to a peak above 6,000 ML/day. The flow downstream at Wangaratta may reach 5,000 ML/day in the next day or two.
Figure 1 - Kiewa River at Bandiana on 26 April 2016 (left) at a flow around 170 ML/day and on 11 May 2016 (right) at a flow around 3,500ML/day with old pylons mostly submerged following heavy rain over the upper catchments. Photos: Adam McLean, MDBA and Ross Hillary, Water NSW.
River operations
Red alerts for blue-green algae have been lifted on the River Murray, between Lake Hume and Yarrawonga Weir inclusive but remain in place downstream to Lock 9. The alerts apply to the main channel of the river as well as many anabranches and connected lakes and wetlands. Non-toxic blue-green algae has also been detected in South Australian reaches of the Murray. More information is available from NSW DPI, Goulburn Murray Water,SA DEWNR and the MDBA website.
With the irrigation season finished, releases from the upper Murray storages have been wound back to minimumsand operations are moving into what has traditionally been called storing mode. This week’s rainfall has brought an increase to inflows and storage levels and has started to wet the catchmentsfollowing the hot and dry conditions that have prevailed this year. Total MDBA storage increased 63 GL this week, with the active storage now 2,303 GL (27% capacity). Storage levelsare still very low and will require prolonged above-average rainfall in coming months to refill.
There is a good chance of above-average rainfall in coming months with the Bureau of Meteorology reporting that all international models suggest the tropical Pacific Ocean will continue to cool, with seven out of eight models exceeding La Niña thresholds by September 2016 (BoM notes individual model outlooks show a large spread between neutral and La Niña scenarios).
The Bureau's ENSO Outlook remains at La Niña WATCH, based on recent changes in the tropical Pacific Ocean and atmosphere, combined with current climate model outlooks. This means the likelihood of La Niña forming later in 2016 is around 50%.Typically during La Niña, winter-spring rainfall is above average over northern, central and eastern Australia but such rainfall is not guaranteed.
At Dartmouth Reservoir, the storage volume increased 15 GL to 1,680 GL (44% capacity) this week. The release from Dartmouth, measured at Colemans, remains at the minimum rate of 200 ML/day.
At Hume Reservoir, the storage volume increased 34 GL to 587 GL (20% capacity). Releases were raised temporarily to 750 ML/day over the weekend to maintain the minimum target flow of 1,200 ML/day at Doctors Point. Releases were reduced once theflow from the Kiewa River was sufficient toincrease the Doctors Point flow above minimums.
At Lake Mulwala the pool level reduced from the high end of its normal operating range to the low end this week with levels falling from 124.85 m AHD to 124.649 m AHD (strong winds may be affecting readings by temporarily pushing water upstream away from theweir). The weir pool was high at the beginning of the week due to the rainfall at the beginning of the month and subsequent reduction in irrigation diversions. Releases from Yarrawonga went as low as 3,300 ML/day over the weekend before being increased to 4,000 ML/day after the rain event on the weekend. This has created airspace to manage the inflows from the Ovens and Kiewa Rivers that will arrive over the coming week. In response, Yarrawonga releases are forecast to be increased to around 7,000 ML/day over the coming week based on current tributary inflows.
On the Edward-Wakoolsystem, the Edward River Offtake has fallen from around 860 ML/day to 570 ML/day while Gulpa Offtake remained relatively steady at 190 ML/day. The gates at these offtakes were raised out of the water on 9 May. This will allow the levels in the Edward and Gulpa Creeks to fluctuate as flows downstream of Yarrawonga vary and will also allow unimpeded fish passage between theMurray and Edward systems. At Stevens Weir, WaterNSW has advised that the weir pool level will fall gradually over the coming weeks in preparation for the annual winter drawdown. However the exact timing of the drawdown has yet to be finalised – seeWaterNSWfor more information.
On the Goulburn River, the flow at McCoys Bridge has averaged 800 ML/day this week. Small volumes of environmental water continue to boost the flow above the normal end of system target flow for this time of year. There may be slight rises in the flows at McCoys over the coming weeks due to rainfall in unregulated creeks in the Goulburn catchment.
At Torrumbarry Weir, the pool level is currently 10 cm below the full supply level (FSL). Beginning this Sunday, the pool level will begradually lowereduntil it reaches around 40 cm below FSL at the end of May. Diversions to National Channel have reduced to 300 ML/day this week after the rainfall. The irrigation season is due to finish on 15 May but diversions through National Channelare likely to continue through winter to provide base flows in Gunbower Creek. The flowdownstream of Torrumbarry Weir is currently under 5,000 ML/day but is expected to rise slightly over 5,000 ML/day in the coming week.Further downstream, inflows to the Murray from the Murrumbidgee River at Balranald have increased to over 500 ML/day as WaterNSW lowers Redbank Weir to undertake essential maintenance works.
Downstream at Euston Weir, flows have risen to 7,900 ML/day. This rise is largely due to the reduction in diversions through National Channel after the rainfall event at the beginning of the month. The target pool level is 47.30 m AHD in May,30 cm below FSL,and is being undertaken as part of the on-going weir pool level variability trial.
At the Menindee Lakes, the storage volume remains unchanged this week at a very low 49 GL (3% capacity).At the confluence of the Darling and Murray Rivers at Wentworth, the flow has risen to 6,600ML/day and is expected to rise to around 7,500 ML/day by the middle of next week. The weir pool was held around 10cm above full supply level during the irrigation season to assist water users on the Lower Darling arm of the weir pool. The pool level is currently being lowered to target FSL due to reduced demand.
At Lake Victoria, the storage volume increased by 14 GL to 230 GL (34% capacity) and is forecast to rise to around 310 GL by the end of May.
In years when there is no water available from Menindee Lakes, Lake Victoria can have a large influence on release rates from upstream storages in autumn. The normal target volume for Lake Victoria is 350 GL by the end of May.With the travel time from Hume to Lake Victoriaat about three weeksthe targeting of this volume requires releasing flows in advance, based on forecast irrigation demands, weather and other factors.Normally this might mean that flow downstream of Yarrawonga Weir remains close to channel capacity in April.
This year,however, the target volume was relaxed as a water conservation measure due to the prevailing dry conditions, low storage levels and expected low opening allocations. The relaxation can reduce overall evaporative losses as well as increasing the capacity for Lake Victoria to capture future inflows from tributaries downstream of Hume Dam. As a resultYarrawonga releases averaged 7,000 ML/day in April instead of flows nearerto channel capacity. This is estimated to have reduced releasesfrom upstream storages by 50-100 GL.It has also reduced the flow rateand subsequent erosional forces through the Barmah Choke and allowed the upper part of the banks to dry out at a time when the Murray would naturally have been very low.
The flow into South Australia is currently around 3,000 ML/day. Flows to South Australia are being boosted slightly by environmental returns from the Broken, Goulburn and Campaspe Rivers.
At the Lower Lakes, the 5-day average water level in Lake Alexandrina is 0.56 m AHD. During the week strong winds, very large swells and high tides were experienced at the barrages.
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DAVID DREVERMAN
Executive Director, River Management
Water in Storage Week ending Wednesday 11 May 2016
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 / 444.34 / 1 680 / 44% / 71 / 1 609 / +15
Hume Reservoir / 192.00 / 3 005 / 174.55 / 587 / 20% / 23 / 564 / +34
Lake Victoria / 27.00 / 677 / 22.82 / 230 / 34% / 100 / 130 / +14
Menindee Lakes / 1 731* / 49 / 3% / (- -) # / 0 / -0
Total / 9 269 / 2 546 / 27% / - - / 2 303 / +63
Total Active MDBA Storage / 27% ^
Major State Storages
Burrinjuck Reservoir / 1 026 / 337 / 33% / 3 / 334 / +6
Blowering Reservoir / 1 631 / 806 / 49% / 24 / 782 / +33
Eildon Reservoir / 3 334 / 1 028 / 31% / 100 / 928 / +5
*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 10 May 2016
Storage / Active Storage (GL) / Weekly Change (GL) / Diversion (GL) / This Week / From 1 May 2016Lake Eucumbene - Total / 1 379 / n/a / Snowy-Murray / +12 / 18
Snowy-Murray Component / 795 / n/a / Tooma-Tumut / +7 / 7
Target Storage / 1 290 / Net Diversion / 5 / 11
Murray 1 Release / +24 / 27
Major Diversions from Murray and Lower Darling (GL) *
New South Wales / This Week / From 1 July 2015 / Victoria / This Week / From 1 July 2015Murray Irrig. Ltd (Net) / 0.0 / 454 / Yarrawonga Main Channel (net) / 0 / 247
Wakool Sys Allowance / 1.4 / 85 / Torrumbarry System + Nyah (net) / 0 / 504
Western Murray Irrigation / 0.1 / 20 / Sunraysia Pumped Districts / 0.2 / 104
Licensed Pumps / 0.9 / 199 / Licensed pumps - GMW (Nyah+u/s) / 2.2 / 44
Lower Darling / 0.1 / 10 / Licensed pumps - LMW / 5.4 / 285
TOTAL / 2.5 / 768 / TOTAL / 7.8 / 1184
* 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 the delivery of additional environmental water. / Entitlement this month / 93.0 *
Flow this week / 20.6 / (2 900 ML/day)
Flow so far this month / 32.3
Flow last month / 159.5
Salinity (EC) (microSiemens/cm at 25o C)
Current / Average over the last week / Average since 1 August 2015Swan Hill / 60 / 60 / 70
Euston / - / - / -
Red Cliffs / 110 / 110 / 120
Merbein / 110 / 120 / 120
Burtundy (Darling) / 1 700 / 1 740 / 1 300
Lock 9 / 120 / 120 / 120
Lake Victoria / 200 / 190 / 210
Berri / 240 / 240 / 210
Waikerie / 260 / 270 / 270
Morgan / 240 / 230 / 270
Mannum / 270 / 270 / 310
Murray Bridge / 290 / 290 / 330
Milang (Lake Alex.) / 880 / 880 / 810
Poltalloch (Lake Alex.) / 670 / 610 / 670
Meningie (Lake Alb.) / 2 090 / 2 050 / 2 100
Goolwa Barrages / 9 220 / 5 630 / 1 370
River Levels and Flows Week ending Wednesday 11 May 2016
Minor 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 / - / - / - / 9 760 / F / 4 910 / 1 660
Jingellic / 4.0 / 2.56 / 209.08 / 12 250 / R / 4 870 / 1 920
Tallandoon ( Mitta Mitta River ) / 4.2 / 2.03 / 218.92 / 2 310 / F / 1 140 / 650
Heywoods / 5.5 / 1.51 / 155.14 / 600 / S / 700 / 4 540
Doctors Point / 5.5 / 1.95 / 150.42 / 3 850 / R / 2 000 / 5 090
Albury / 4.3 / 1.04 / 148.48 / - / - / - / -
Corowa / 4.6 / 0.95 / 126.97 / 2 710 / R / 2 320 / 6 670
Yarrawonga Weir (d/s) / 6.4 / 0.76 / 115.80 / 3 950 / S / 3 740 / 5 920
Tocumwal / 6.4 / 1.30 / 105.14 / 3 970 / R / 4 150 / 6 720
Torrumbarry Weir (d/s) / 7.3 / 1.69 / 80.24 / 4 860 / F / 5 530 / 5 590
Swan Hill / 4.5 / 1.24 / 64.16 / 6 310 / F / 6 290 / 5 170
Wakool Junction / 8.8 / 2.92 / 52.04 / 7 570 / R / 7 120 / 5 670
Euston Weir (d/s) / 9.1 / 1.59 / 43.43 / 7 920 / R / 7 120 / 5 310
Mildura Weir (d/s) / - / - / 6 770 / F / 6 180 / 4 650
Wentworth Weir (d/s) / 7.3 / 2.93 / 27.69 / 6 580 / F / 5 970 / 4 040
Rufus Junction / - / 2.79 / 19.72 / 2 490 / F / 2 610 / 2 960
Blanchetown (Lock 1 d/s) / - / 0.56 / - / 2 520 / R / 2 350 / 2 330
Tributaries
Kiewa at Bandiana / 2.8 / 2.60 / 155.83 / 3 280 / R / 1 110 / 310
Ovens at Wangaratta / 11.9 / 9.39 / 147.07 / 4 490 / R / 1 180 / 250
Goulburn at McCoys Bridge / 9.0 / 1.36 / 92.78 / 730 / S / 790 / 770
Edward at Stevens Weir (d/s) / 5.5 / 1.04 / 80.81 / 840 / F / 670 / 570
Edward at Liewah / - / 1.30 / 56.68 / 690 / F / 680 / 620
Wakool at Stoney Crossing / - / 1.47 / 54.96 / 540 / R / 440 / 370
Murrumbidgee at Balranald / 5.0 / 0.94 / 56.90 / 560 / F / 490 / 340
Barwon at Mungindi / 6.1 / 3.12 / - / 0 / F / 10 / 20
Darling at Bourke / 9.0 / 3.79 / - / 0 / F / 0 / 0
Darling at Burtundy Rocks / - / 0.60 / - / 0 / F / 0 / 0
Natural Inflow to Hume / 6 840 / 1 340
(i.e. Pre Dartmouth & Snowy Mountains scheme)
Weirs and LocksPool levels above or below Full Supply Level (FSL)
Murray / FSL (m AHD) / u/s / d/s / FSL (m AHD) / u/s / d/sYarrawonga / 124.90 / -0.25 / - / No. 7 Rufus River / 22.10 / +0.02 / +0.48
No. 26 Torrumbarry / 86.05 / -0.10 / - / No. 6 Murtho / 19.25 / -0.06 / -0.03
No. 15 Euston / 47.60 / -0.31 / - / No. 5 Renmark / 16.30 / +0.02 / +0.10
No. 11 Mildura / 34.40 / +0.04 / +0.16 / No. 4 Bookpurnong / 13.20 / +0.04 / +0.29
No. 10 Wentworth / 30.80 / +0.04 / +0.29 / No. 3 Overland Corner / 9.80 / +0.02 / +0.11
No. 9 Kulnine / 27.40 / +0.02 / -0.03 / No. 2 Waikerie / 6.10 / +0.02 / +0.01
No. 8 Wangumma / 24.60 / -0.01 / +0.06 / No. 1 Blanchetown / 3.20 / -0.09 / -0.20
Lower LakesFSL = 0.75 m AHD
Lake Alexandrina average level for the past 5 days (m AHD) / 0.56Barrages Fishways at Barrages
Openings / Level (m AHD) / No. Open / Rock Ramp / Vertical Slot 1 / Vertical Slot 2 / Dual Vertical SlotsGoolwa / 128 openings / 0.48 / All closed / - / Open / Open / -
Mundoo / 26 openings / 0.51 / All closed / - / - / - / Closed
Hunters Creek / - / - / - / - / Open / - / -
Boundary Creek / 6 openings / - / All closed / - / Open / - / -
Ewe Island / 111 gates / - / All closed / - / - / - / Open
Tauwitchere / 322 gates / 0.52 / All closed / Open / Open / Open / -
* Mundoo Barrage Dual vertical slots are currently under construction.
AHD = Level relative to Australian Height Datum, i.e. height above sea level
GPO Box 1801 Canberra ACT 2601Telephone: 02 6279 0100Facsimile: 02 6248 8053
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Week ending Wednesday 11 May 2016
State Allocations (as at 11 May 2016)
NSW - Murray Valley / Victorian - Murray ValleyHigh security / 97%
General security / 23%
/ High reliability / 100%
Low reliability / 0%
NSW – MurrumbidgeeValley / Victorian- GoulburnValley
High security / 95%
General security / 37%
/ High reliability / 90%
Low reliability / 0%
NSW - Lower Darling / South Australia – MurrayValley
High security / 80%
General security / 0%
/ High security / 100%
NSW : /
VIC : /
SA : /
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