River Murray Weekly Report
For the weeks ending Wednesday, 26th December 2012 & 2nd January 2013
Trim Ref: D12/52143
Rainfall and Inflows
In the week ending 26 December 2012, showers and thunderstorms were a feature of the weather in south-eastern Australia. This resulted in rainfall totals over 25 mm for much of southern Queensland and eastern New South Wales (Map 1). Notable totals in Queensland were 99 mm at Texas in the Darling Downs, 77 mm at Augathella in the Warrego catchment and 53 mm at Munnaweena in the Maranoa catchment. In New South Wales 115 mm was recorded at Woolbrook and 99 mm at Pindari Dam on the northwest slopes, 89 mm at Glen Innes AP AWS on the northern tablelands, 70 mm at Mudgee AP AWS and 68 mm at Bathurst on the central tablelands, and 45 mm at Gunning on the southern tablelands.
Map 1 - Murray-Darling Basin rainfall for the week ending 26 December 2012 (Source: Bureau of Meteorology)
The following week (ending 2 January 2013) was considerably drier (Map 2). Earlier this week showers and thunderstorms persisted in southern Queensland and north-eastern New South Wales. In Queensland 52 mm was recorded at Fairfield in the Maranoa catchment, 34 mm at Nindigully in the Warrego catchment and 30 mm at Southwood in the Darling Downs. In New South Wales 50 mm was recorded at Pallamallawa on the northwest plains, 47 mm at Inverell on the northern tablelands and 42mm at Gravesend on the northwest slopes. Elsewhere in the Basin and in the second half of this week conditions were dry across the Basin. Conditions are forecast to be dry and very hot for the coming week.
Map 2 - Murray-Darling Basin rainfall for the week ending 2 January 2013 (Source: Bureau of Meteorology)
In the upper Murray tributaries, flows have been receding over the last two weeks, although there were some brief small increases in flow at some sites following the rain prior to Christmas. On the Mitta Mitta River, the flow at Hinnomunjie has receded from around 450 ML/day to 220 ML/day. On the Ovens River, the flow at Rocky Point averaged around 700 ML/day in the week prior to Christmas, but has now receded to 380 ML/day. Flows at many sites in the upper Murray tributaries are now at their lowest levels since early 2010.
December 2012 Summary
Rainfall across the Murray-Darling Basin in December 2012 was generally average or below average with areas of very much below average in inland NSW. Small parts of inland NSW recorded their lowest December total on record. Above average rainfall was recorded in parts of north-eastern NSW and south-eastern Queensland. (Map 3). Overall the month was the 37th driest December for the Basin in 113 years of records, with a total that was 38% below the historical average.
The recent trend of above average maximum temperatures continued during December. In most parts of the Basin, the maximum temperatures were 1-3 degrees Celsius above the long term monthly average. Minimum temperatures were also slightly higher, being 0-2 degrees Celsius above average.
Murray system inflows for December 2012 totalled around 300 GL, compared with 550 GL for December 2011 and the long term average for December of around 420 GL.
Map 3 - Murray-Darling Basin rainfall deciles for December 2012 (Source: Bureau of Meteorology)
2012 Rainfall Summary
According to the Bureau of Meteorology, 2012 recorded near average rainfall and was Australia’s 40th wettest year since the comparable historic record began in 1900 (Map 4).
The rainfall did not fall evenly throughout the year during 2012. Following on from 2010 and 2011 - the wettest two year period on record for Australia - the first three months of the year saw above average rainfall in the Basin.
During this period, record rainfall and system inflows took place. At the end of February and into early March, parts of southeast Australia recorded their wettest 7-day period on record. Record 7 day totals included 525 mm at Mount Buffalo, 442 mm at Thredbo Village, 362 mm at Batlow, 354 mm at Falls Creek, 346 mm at Chiltern and 329 mm at Burrinjuck Dam. The exceptionally heavy rainfall led to widespread flooding in the southern parts of NSW and northern Victoria, including the highest floods since 1974 at several locations.
In the upper Darling catchment, there was a significant rainfall event in late January-early February that generated high flows in the Namoi, Gwydir, Moonie and Balonne/Culgoa/Bokhara river systems resulting in a peak flow in the Darling River at Bourke of 240,000 ML/day.
From April onwards rainfall was generally average or below average. Across the Basin, rainfall during winter was slightly below average and ranked 43rd driest out of 113 years of record. Rainfall during spring was considerably drier and ranked 11th driest.
Map 4 - Murray-Darling Basin rainfall deciles for 1 January to 31 December 2012 (Source: Bureau of Meteorology)
River Operations
MDBA active storage decreased by 416 GL over the past two weeks and is currently 7,403 GL, or 86% capacity. At Dartmouth Reservoir, the storage volume decreased by 7 GL and is 3,815 GL (99% capacity). The release, measured at Colemans, was around 600 ML/day until late in December, when it was briefly increased to around 2,600 ML/day. This ‘pulse’ aims to benefit the environment of the Mitta Mitta River. The release is currently at 600 ML/day.
At Hume Reservoir, the storage volume reduced by 213 GL to 2,362 GL (79% capacity). The release averaged around 14,600 ML/day last week, increasing to an average of 20,400 ML/day this week as conditions turned dry and irrigation demand increased.
At Yarrawonga Weir, total diversions at the irrigation offtakes increased this week to 76 GL, compared with around 60 GL/week over the last few weeks. The pool level in Lake Mulwala averaged 124.73mAHD over the last two weeks, and ranged between 124.67 m AHD in late December when the pool was drawn down to supply additional demand at Mulwala Canal and the current level of 124.77 m AHD. The downstream release was around 7,500 ML/day for much of the last two weeks. The release reduced briefly to 6,000 ML/day late in December to help maintain Yarrawonga pool level, before increasing to the current rate of 9,100 ML/day. The release is expected to reduce to 8,500ML/day in the coming week.
On the Edward River system, flow through the Edward and Gulpa offtakes has varied in response to demand and the effect of falling river levels in the River Murray. Inflow through the Edward Escape averaged around 1,200 ML/day last week and earlier this week before increasing to the current rate of 1,950 ML/day. Diversions to the Wakool Main Canal have gradually increased over the last two weeks
from 1,700 ML/day to around 2,000 ML/day. Diversions to Wakool River and Yallakool Creek were around 100 ML/day and 220 ML/day respectively. The diversion to Colligen Creek reduced this week from an average of 160 ML/day last week to the current flow of 100 ML/day in an attempt to maximise the diversion to Wakool Main Canal. The diversion to Colligen Creek will return to the normal summer operating level of around 170 ML/day early next week. Flow downstream of Stevens Weir averaged around 670 ML/day over the last two weeks. The release fell below the normal summer operating minimum of 600 ML/day to around 450 ML/day for a week over the Christmas period due to higher than expected upstream demand, but has since increased and is currently 920 ML/day.
On the Goulburn River at McCoys Bridge, flows have ranged between 1,600 ML/day and 2,400ML/day, averaging 2,000 ML/day as delivery of water traded from the Goulburn Valley to the Murray Valley continues. At Torrumbarry Weir, the diversion at National Channel averaged around 2,800 ML/day. Downstream of Torrumbarry Weir, the flow reduced from 6,400 ML/day to 4,800ML/day last week and continues around this rate.
On the lower Murrumbidgee River, the flow at Balranald averaged 2,100 ML/day. The flow is expected to be around 1,500 ML/day next week. Downstream on the Murray at Euston the flow reduced from 9,000 ML/day to 7,200 ML/day, and is expected to continue receding to around 4,500 ML/day later next week.
Total storage at Menindee Lakes decreased by 153 GL over the past two weeks to 1,347 GL (78% capacity). The release (measured at Weir 32) was steady at 6,900 ML/day. The release will be reduced to 6,000 ML/day by Friday 4 January 2013 and will reduce further to 5,000 ML/day starting 10January (see attached flow advice for details). Downstream on the lower Darling River, the flow at Burtundy slowly receded to 5,600 ML/day. On the River Murray at Wentworth, the flow reduced from 14,000 ML/day to 11,300 ML/day.
At Lake Victoria the volume reduced by 44 GL to 553 GL (82% capacity) and is expected to continue falling over the coming weeks. The flow to South Australia receded from 18,500 ML/day to around 10,000 ML/day where it is expected to be for the remainder of January. With Menindee Lakes expected to fall below 1,300 GL at the end of the first week in January, the delivery to South Australia of 3,000ML/day of Additional Dilution Flow (ADF) will cease. However flow to South Australia will be sustained in excess of normal entitlement flow of 7,000 ML/day through January with the trade of about 100 GL of environmental water.
The flow at Lock 1 fell from 15,400 ML/day to 9,000 ML/day. At the Lower Lakes, the 5 day average level for Lake Alexandrina gradually reduced from 0.78 m AHD to 0.70 m AHD, with an estimated release of 3,000 ML/day from the barrages.
For media inquiries contact the Media Officer on 02 6279 0141
DAVID DREVERMAN
Executive Director, River Management
Water in Storage Week ending Wednesday 26 Dec 2012
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 / 485.49 / 3 823 / 99% / 71 / 3 752 / +1
Hume Reservoir / 192.00 / 3 005 / 189.28 / 2 487 / 83% / 23 / 2 464 / -87
Lake Victoria / 27.00 / 677 / 26.09 / 569 / 84% / 100 / 469 / -28
Menindee Lakes / 1 731* / 1 427 / 82% / (480 #) / 947 / -72
Total / 9 269 / 8 306 / 90% / - - / 7 632 / -186
Total Active MDBA Storage / 89% ^
Major State Storages
Burrinjuck Reservoir / 1 026 / 657 / 64% / 3 / 654 / -27
Blowering Reservoir / 1 631 / 1 441 / 88% / 24 / 1 417 / -28
Eildon Reservoir / 3 334 / 3 090 / 93% / 100 / 2 990 / -34
* Menindee surcharge capacity – 2050 GL ** All Data is rounded to nearest GL **
# NSW takes control of Menindee Lakes when storage falls below 480 GL, and control reverts to MDBA when storage next reaches 640 GL
^ % of total active MDBA storage
Snowy Mountains Scheme Snowy diversions for week ending 25 Dec 2012
Storage / Active Storage (GL) / Weekly Change (GL) / Diversion (GL) / This Week / From 1 May 2012Lake Eucumbene - Total / 2 311 / -36 / Snowy-Murray / +2 / 498
Snowy-Murray Component / 984 / +2 / Tooma-Tumut / +0 / 195
Target Storage / 1 510 / Net Diversion / 2 / 303
Murray 1 Release / +2 / 742
Major Diversions from Murray and Lower Darling (GL) *
New South Wales / This Week / From 1 July 2012 / Victoria / This Week / From 1 July 2012Murray Irrig. Ltd (Net) / 50.7 / 754 / Yarrawonga Main Channel (net) / 12 / 170
Wakool Sys Allowance / 3.3 / 18 / Torrumbarry System + Nyah (net) / 14.4 / 209
Western Murray Irrigation / 1.4 / 13 / Sunraysia Pumped Districts / 5.3 / 59
Licensed Pumps / 6.6 / 117 / Licensed pumps - GMW (Nyah+u/s) / 0.6 / 21
Lower Darling / 4.1 / 45 / Licensed pumps - LMW / 7.5 / 126
TOTAL / 66.1 / 947 / TOTAL / 39.8 / 585
* Figures derived from estimates and monthly data. 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 Additional Dilution Flow and traded environmental water. / Entitlement this month / 217.0 *
Flow this week / 114.6 / (16 400 ML/day)
Flow so far this month / 467.7
Flow last month / 491.4
Salinity (EC) (microSiemens/cm at 25o C)