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RIVER MURRAY WEEKLY REPORT FOR THE WEEK ENDING WEDNESDAY, 3RD AUGUST 2016 Trim Ref: D16/25862

Rainfall and inflows

A strong cold front delivered most of this week’s Basin rainfall. Significant totals were recorded throughout much of New South Wales with Armidale receiving 50 mm and Bathurst 46 mm. Falls were heavier across the Kiewa, Ovens, Broken and Goulburn River catchments of Victoria, where widespread rainfall between 30 mm and 70 mm were recorded (see Map 1). Isolated higher totals occurred in the mountains with Mount Buffalo receiving 120 mm of rainfall. The highest totals in South Australia were once again in the Mount Lofty Ranges, with Mount Compass receiving 46 mm.

Map 1 - Murray-Darling Basin rainfall week ending 3rd August 2016 (Source: Bureau of Meteorology)

The already saturated catchments were very responsive to this week’s rainfall. While the heaviest falls were downstream of Hume Reservoir, reasonable falls in the upper Murray delivered a peak flow at Jingellic of 27,500 ML/day. Upstream of Dartmouth Dam relatively light rainfall yielded a peak on the Mitta Mitta River at Hinnomunjie of around 4,000 ML/day.

The Kiewa River delivered over 12,000 ML/day to the Murray following the rainfall, while the Ovens at Wangaratta reached 65,000 ML/day. Inflows from these two tributaries were higher than last week, despite heavier rainfall last week – reflecting the current saturated catchment conditions. The peak flows observed were the highest since December 2010.

Further rainfall is forecast for the coming week which may lead to renewed streamflow rises. For the latest flood warnings and flood watches see the Bureau of Meteorology (BoM) website.

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July 2016 Summary

Rainfall in July 2016 was average to above-average for most of the Murray–Darling Basin (see

Map 2), with the high-yielding areas of the Snowy Mountains and Victorian Alps recording rainfall in

excess of 200 mm.

The Bureau of Meteorology has reported that overall the Basin recorded an average rainfall of 45 mm,

which is 13% above average for July. Victoria recorded rainfall 41% above the average, making this

July the 10th wettest on record. In NSW, many towns within the Basin such as Albury and Wagga

Wagga recorded their wettest July in at least 20 years. In South Australia, areas near the Lower

Lakes, including Strathalbyn, Macclesfield and Callington, recorded their highest July rainfall on

record.

Map 2 - Murray-Darling Basin rainfall deciles for July 2016 (Source: Bureau of Meteorology)

Above average rainfall in May and June has made catchments very responsive. As a result this

month’s high rainfall delivered significant Murray System inflows (excluding Snowy, Darling, inter-

valley trade and environmental inflows) of around 1,950 GL—this is the highest July inflow since 1996

and higher July inflows have only been observed in about 18% of years. For comparison, the long-

term average inflow for July is approximately 1,230 GL.

At Hume Reservoir, the inflow (excluding flows from the Snowy scheme and upstream of Dartmouth

Reservoir) totalled around 620 GL (in the highest 11% of records), which is the highest July inflow

since 1995. At Dartmouth Reservoir, inflows totalled around 260 GL (wettest 6%)—the highest for July

since 1981.

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Estimated evaporation losses from MDBA storages for July 2017 are provided in Table 1. Evaporation

is estimated by multiplying the surface area of the storage by the net evaporation. Net evaporation is

derived by subtracting the rainfall recorded at the storage from this calculated evaporation. At Hume

and Dartmouth Reservoirs, rainfall exceeded evaporation hence there was a net gain of water at these

storages.

Table 1: Monthly evaporation figures for MDBA storages

Storage *Approximate (net) evaporative loss in July

2016 (GL)

Average storage volume in July 2016 (GL)

Percentage net evaporative loss in July

2016

Dartmouth -7.2 1903.9 -0.4

Hume -13.3 1508.2 -0.9

Lake Victoria 2.5 542.9 0.5

Menindee Lakes 1.5 84.6 1.8

* Evaporative loss from storage = surface area of the storage x net evaporation. Net evaporation = measured evaporation (using a ‘pan’ instrument) - rainfall.

River operations

MDBA total storage increased by 373 GL this week to an active storage of 4,617 GL (55% capacity).

At Dartmouth Reservoir, the storage volume increased by 65 GL to 2,083 GL (54% capacity). MDBA advises that Dartmouth Dam could only fill this season if extreme wet conditions are observed. The release remains at a minimum flow of 200 ML/day. On the Mitta Mitta River downstream of Dartmouth, inflows from Snowy Creek contributed to a peak flow at Tallandoon of 6,500 ML/day.

At Hume Reservoir, the storage volume increased by 295 GL (almost 10% of total storage) over the past week to 2,128 GL (71% capacity). Releases from Hume currently remain at a minimum flow of 600 ML/day in order to conserve resource, however with the catchments saturated only one or two significant rainfall events could fill the storage. As storage levels rise over the coming weeks MDBA could be expected to commence ‘airspace management’ releases aimed at providing a measure of flood protection without jeopardising the ability to fill the reservoir. Further details about flood management at Hume Dam are available on the MDBA website. Even if initial releases are at modest rates, when combined with the inflows from the Kiewa River they may be sufficient to exceed the normal channel capacity rate of 25,000 ML/day. Regular updates on Hume storage levels and releases will be provided in future weekly reports, however communities are reminded that all Flood Watches and Warnings are issued by BoM.

In their latest Climate and water outlook video, BoM advises of an increased risk of flooding across parts of Australia. MDBA strongly recommends that communities downstream of Hume Dam, and even those afforded some flood protection by levee systems, commence their flood preparations. NSW and Victoria State Emergency Service websites provide information on preparing for floods.

This week’s rainfall over the saturated catchments of the Kiewa, Ovens, Broken and Goulburn catchments built upon the already high inflows to the River Murray downstream of Hume. As previously mentioned, inflows from the Kiewa River peaked above 12,000 ML/day (see Photo 1) whilst the Ovens River at Wangaratta peaked near 65,000 ML/day.

These high flows have resulted in releases from Yarrawonga Weir remaining at or above 33,000 ML/day over the past week. Releases were temporarily reduced from the 42,000 ML/day peak ordered earlier in the week before being increased to 44,000 ML/day on Saturday as upstream inflows arrived. Following this latest rainfall event releases have been increased to 66,000 ML/day as of Thursday morning and are expected to peak around this level. Due to these high flows no environmental water has been released from Hume Reservoir.

Hume rises 10 percentage points in a week

Unregulated flows continue

Yarrawonga Weir release to peak near 66,000 ML/day.

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Picture 1 – The swollen Kiewa River at Bandiana. Photo: Tom Zouch, MDBA.

Flow downstream of Yarrawonga has remained above channel capacity (near 10,000 ML/day) for the last 6 weeks. Regulators situated along this river reach are open, allowing the passage of water from the main river channel into the Barmah-Millewa Forest.

On the Edward River, the flow at Toonalook has increased to 6,500 ML/day and is still rising, in large part due to returning flows from the Millewa Forest. Downstream of Stevens Weir, the flow is around 5,000 ML/day and is forecast to continue rising. These flows are greater than the channel capacity, resulting in water passing through Werai Forest and into the Niemur River system. Inflows from Billabong Creek are around 1,800 ML/day, which is contributing to a flow on the Edward River at Moulamein of 4,100 ML/day.

The Goulburn River at McCoys Bridge slowly receded to around 6,000 ML/day before beginning to rise as inflows from the latest rainfall event arrive. Similar to the Kiewa and Ovens River, these higher flows are from run-off, not environmental releases. Over the coming days the flow is expected to increase dramatically and may approach the minor flood level. For more information please see the latest BoM flood warning for the Goulburn River.

On the Murray at Torrumbarry Weir, the downstream flow has risen to 19,000 ML/day. Given the rising flows downstream of Yarrawonga and expected increased inflows from the Goulburn River, the downstream flow from Torrumbarry is expected to continue rising to above 30,000 ML/day later in the week. At these flow rates water will begin naturally inundating the Koondrook-Perricoota Forest. Following a winter drawdown Torrumbarry weir pool is currently 85.80 m AHD (25 cm below FSL) and will be further raised close to Full Supply Level (FSL) in the coming weeks. At Swan Hill flows have increased to 16,200 ML/day and will steadily increase over the next week.

At Balranald on the Murrumbidgee River, the flow is steady at 8,400 ML/day. Downstream on the Murray at Euston, the flow is around 24,800 ML/day and is expected to continue rising over the next fortnight. The Euston weir pool is currently around 10 cm below FSL.

On the Darling River, the storage at Menindee Lakes increased by 19 GL to 155 GL (9% capacity). Releases from Menindee Lakes into the lower Darling River commenced 29 July. The release from Lake Wetherell is expected to be gradually increased to a maximum rate of 1,500 ML/day before tapering off to approximately 150 to 200 ML/day to prolong the flow for as long as possible. The release from Menindee Lakes as currently planned by NSW water managers is unlikely to be of sufficient volume to provide connection to the River Murray, however this forecast will be reviewed as the flow makes its way down the lower Darling.

Downstream at the junction of the lower Darling and Murray, the flow at Wentworth is around 23,000 ML/day and is forecast to gradually rise over the coming weeks. Lock 9 is currently 18 cm above FSL and Lock 8 is 10 cm above FSL. The river is flowing freely through Lock 7 as the drop boards have been removed. The higher flows are resulting in the current river height being around 50 cm above FSL. More information on the planned management of these and other River Murray weir pools for 2016-17 is available on the MDBA website. The gates at the Mullaroo offtake regulator have been laid flat to maximise the flow into the Mullaroo Creek (see Picture 2).

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Picture 2 – The Mullaroo regulator has been fully opened to maximise the flow down the Mullaroo Creek – Photo: Peter Webber,

SA Water.

The total storage at Lake Victoria was reduced by 7 GL this week to 600 GL (89% capacity). MDBA is lowering Lake Victoria to minimise disturbance to Aboriginal cultural heritage material. MDBA operates in accordance with the Lake Victoria Operating Strategy (LVOS), which requires the period of time that the water level in Lake Victoria is held high to be minimised in order to limit erosion and allow for revegetation to protect important cultural heritage. With high flows in the River Murray likely to persist for several weeks at least, MDBA is lowering the level of Lake Victoria before re-filling it as late as possible. The extent to which the storage is lowered and the timing on when it is re-filled will be dependent on the duration of high upstream inflows.

As the flow to South Australia is forecast to remain higher than South Australia’s current entitlement for at least the next few weeks, unregulated flows are available in the Murray and Edward River systems downstream of Hume Reservoir. The daily flow to South Australia has increased to over 25,000 ML/day this week, and is expected to continue rising over the next week. Whilst it is unusual, it is not unprecedented to see such unregulated flows at a time when water allocations remain low.

Further downstream the South Australian Department of Environment, Water and Natural Resources (DEWNR) have raised Lock 5 and Lock 2 weir pools to the top of their normal operating range (16.30 and 6.10 m AHD respectively). Further information can be found in the latest DEWNR River Murray Flow Report

At the Lower Lakes, recent local rainfall has combined with the high River Murray flows to increase the 5-day average water level at Lake Alexandrina to 0.82 m AHD. Barrage releases over the past week have aimed to both scour away accumulated sand near the Murray mouth and to improve salinity levels in the Coorong.

For media inquiries contact the Media Officer on 02 6279 0141

DAVID DREVERMAN

Executive Director, River Management

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Water in Storage Week ending Wednesday 03 Aug 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 3 856 453.82 2 083 54% 71 2 012 +65

Hume Reservoir 192.00 3 005 187.20 2 128 71% 23 2 105 +295

Lake Victoria 27.00 677 26.36 600 89% 100 500 -7

Menindee Lakes 1 731* 155 9% (- -) # 0 +19

Total 9 269 4 966 54% - - 4 617 +373

Total Active MDBA Storage 55% ^

Major State Storages Burrinjuck Reservoir 1 026 878 86% 3 875 +83

Blowering Reservoir 1 631 1 225 75% 24 1 201 +36

Eildon Reservoir 3 334 1 628 49% 100 1 528 +149

* 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 02 Aug 2016

Storage Active Storage

(GL) Weekly Change

(GL) Diversion (GL) This Week

From 1 May 2016

Lake Eucumbene - Total 1 572 +69 Snowy-Murray +22 327

Snowy-Murray Component 897 +2 Tooma-Tumut +14 117

Target Storage 1 190 Net Diversion 8 211

Murray 1 Release +34 465

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) 13.0 23 Yarrawonga Main Channel (net) 0 0

Wakool Sys Allowance 0.0 0 Torrumbarry System + Nyah (net) 3.4 22

Western Murray Irrigation 0.1 0 Sunraysia Pumped Districts 0.6 1

Licensed Pumps 1.7 4 Licensed pumps - GMW (Nyah+u/s) 0 0

Lower Darling 0.1 1 Licensed pumps - LMW 1.1 5

TOTAL 14.9 28 TOTAL 5.1 28

* 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 higher than normal for this month due to unregulated flows.

Entitlement this month 124.0 *

Flow this week 156.0 (22 300 ML/day)

Flow so far this month 74.6 Flow last month 322.2

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

Current Average over the last week Average since 1 August 2016

Swan Hill 90 110 140

Euston - - -

Red Cliffs 130 120 130

Merbein 120 120 120

Burtundy (Darling) 1 570 1 610 1 580

Lock 9 120 120 120

Lake Victoria 160 160 160

Berri 150 140 140

Waikerie 180 190 180

Morgan 180 200 190

Mannum 340 360 350

Murray Bridge 380 420 400

Milang (Lake Alex.) 800 800 800

Poltalloch (Lake Alex.) 500 550 450

Meningie (Lake Alb.) 1 660 1 720 1 650

Goolwa Barrages 1 050 1 860 1 050

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River Levels and Flows Week ending Wednesday 03 Aug 2016

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 - - - 8 620 F 7 850 10 840

Jingellic 4.0 3.67 210.19 25 820 R 24 700 27 710

Tallandoon ( Mitta Mitta River ) 4.2 2.70 219.59 5 440 F 4 880 4 710

Heywoods 5.5 1.43 155.06 600 S 600 600

Doctors Point 5.5 2.82 151.29 13 030 R 9 150 8 010

Albury 4.3 1.84 149.28 - - - -

Corowa 4.6 2.79 128.81 12 750 R 10 590 7 720

Yarrawonga Weir (d/s) 6.4 4.05 119.09 32 900 S 37 600 22 460

Tocumwal 6.4 4.90 108.74 36 550 F 35 530 19 030

Torrumbarry Weir (d/s) 7.3 5.01 83.56 18 950 S 17 410 11 670

Swan Hill 4.5 2.76 65.68 16 230 R 12 920 11 790

Wakool Junction 8.8 5.24 54.36 19 940 R 18 300 17 070

Euston Weir (d/s) 9.1 3.70 45.54 24 810 R 24 500 22 190

Mildura Weir (d/s) - - 24 030 F 23 710 20 690

Wentworth Weir (d/s) 7.3 4.12 28.88 22 940 S 22 240 19 540

Rufus Junction - 5.58 22.51 23 640 R 21 120 13 530

Blanchetown (Lock 1 d/s) - 1.55 - 22 420 R 19 080 12 210

Tributaries

Kiewa at Bandiana 2.8 3.05 156.28 14 540 F 12 500 10 980

Ovens at Wangaratta 11.9 12.61 150.29 60 320 R 31 750 23 090

Goulburn at McCoys Bridge 9.0 3.97 95.39 5 970 F 7 170 3 290

Edward at Stevens Weir (d/s) 5.5 3.46 83.24 5 010 F 4 140 3 730

Edward at Liewah - 3.76 59.14 3 810 R 3 730 3 670

Wakool at Stoney Crossing - 1.94 55.44 2 110 R 1 810 1 210

Murrumbidgee at Balranald 5.0 5.44 61.40 7 660 S 7 580 7 390

Barwon at Mungindi 6.1 3.43 - 560 F 690 1 010

Darling at Bourke 9.0 4.42 - 2 490 R 1 710 3 310

Darling at Burtundy Rocks - 0.56 - 0 F 0 0

Natural Inflow to Hume 31 870 56 190

(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 -0.17 - No. 7 Rufus River 22.10 +0.46 +3.27

No. 26 Torrumbarry 86.05 -0.25 - No. 6 Murtho 19.25 +0.03 +1.35

No. 15 Euston 47.60 -0.11 - No. 5 Renmark 16.30 +0.16 +1.15

No. 11 Mildura 34.40 +0.04 +1.18 No. 4 Bookpurnong 13.20 +0.06 +2.06

No. 10 Wentworth 30.80 +0.00 +1.48 No. 3 Overland Corner 9.80 +0.03 +1.38

No. 9 Kulnine 27.40 +0.18 +0.96 No. 2 Waikerie 6.10 +0.30 +1.34

No. 8 Wangumma 24.60 +0.11 +1.57 No. 1 Blanchetown 3.20 -0.05 +0.80

Lower Lakes FSL = 0.75 m AHD

Lake Alexandrina average level for the past 5 days (m AHD) 0.82

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 0.82 All closed - - - Closed

Hunters Creek - - - - Open - -

Boundary Creek 6 openings - 1 - Open - -

Ewe Island 111 gates - All closed - - - Open

Tauwitchere 322 gates 0.81 2 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

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Week ending Wednesday 03 Aug 2016

State Allocations (as at 03 Aug 2016)

NSW - Murray Valley Victorian - Murray Valley

High security 97%

General security 12%

High reliability 35%

Low reliability 0%

NSW – Murrumbidgee Valley

Victorian - Goulburn Valley

High security 95%

General security 44%

High reliability 39%

Low reliability 0%

NSW - Lower Darling

South Australia – Murray Valley

High security 40%

General security 0%

High security 89%

NSW :

http://www.water.nsw.gov.au/Water-management/Water-availability/Water-allocations/Water-allocations-summary/water-allocations-summary/default.aspx

VIC : http://www.nvrm.net.au/allocations/current.aspx

SA : http://www.environment.sa.gov.au/managing-natural-resources/river-murray