River Murray Weekly Report for the Week Ending Wednesday, 21St January 2015
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RIVER MURRAY WEEKLY REPORT ST FOR THE WEEK ENDING WEDNESDAY, 21 JANUARY 2015 Trim Ref: D15/2088 Rainfall and Inflows Humid weather and rain contracted to the northern Basin at the beginning of the week, with quite dry conditions persisting until week’s end when a new trough system brought scattered showers to eastern areas. Highest weekly rainfall totals were recorded across the far northern Basin in Queensland and in north-eastern NSW; with lighter rain in the NSW Riverina and north-eastern Victoria. Most of the western Basin remained dry (Map 1). The highest rain totals in Queensland included 96 mm at Miles, 60 mm at Mungallala, 54 mm at Goondiwindi and 48 mm at Texas. Totals in NSW included 48 mm at Gravesend, 39 mm at Inverell, 34 mm at Grong Grong and 33 mm at Ardlethan. In north-eastern Victoria, there was 37 mm at Wodonga and 26 mm at Barnawartha. Map 1- Murray-Darling Basin rainfall for the week ending 21st January 2015 (Source: Bureau of Meteorology). Stream flows in the upper tributaries are steadily receding following the previous week’s good rainfall. Upstream of Dartmouth Dam, the Mitta Mitta River at Hinnomunjie Bridge fell from 700 ML/day to 300 ML/day. On the upper Murray, the flow at Biggara fell from 1,200 ML/day to 400 ML/day; whilst on the Ovens River, the flow at Wangaratta peaked at 700 ML/day before receding to 340 ML/day. GPO Box 1801 Canberra ACT 2601 Telephone: 02 6279 0100 Facsimile: 02 6248 8053 Email: [email protected] Web: www.mdba.gov.au ABN 13679821382 Page 1 of 9 River Operations • Navigation via Lock 7 lock chamber unavailable from 27 January for 10-12 weeks; • Flow to South Australia increased as environmental water is sent to the Coorong. MDBA total storage decreased by 118 GL this week, with the active storage now 4,963 GL (59% capacity). This is around 1,000 GL less than the long-term average active storage for this time of year (Figure 1). At Dartmouth Reservoir, the storage decreased by 26 GL to 3,159 GL (82% capacity). The release, measured at Colemans gauge, will be reduced over the coming week from 4,800 ML/day to 3,000 ML/day before increasing back to 4,500 ML/day in late January (see attached flow advice). At Hume Reservoir, the storage volume reduced by 64 GL this week with the total storage now at 1,536 GL (51% capacity). The release was increased during the week from 9,400 ML/day to 16,000 ML/day in response to rising downstream demand. Figure 1- MDBA active storage: June 2005 to present. Diversions at the major irrigation offtakes from Lake Mulwala increased this week from 3,000 to 6,500 ML/day. In the absence of rain, diversions are expected to remain reasonably high over coming weeks with many rice crops in the region reaching ‘panicle initiation’ stage. Panicle initiation indicates the start of the reproductive phase of rice development, and represents a cue to rice growers to increase water depths across crops (see Figure 2). The pool level in Lake Mulwala is currently 124.77 m AHD and the downstream release from Yarrawonga Weir is steady at 10,100 ML/day. GPO Box 1801 Canberra ACT 2601 Telephone: 02 6279 0100 Facsimile: 02 6248 8053 Email: [email protected] Web: www.mdba.gov.au ABN 13679821382 Page 2 of 9 On the Edward River system, the combined flow through the Edward River and Gulpa Creek offtakes is steady at around 1,900 ML/day. Diversions to Wakool Main Canal gradually rose throughout the week from 500 ML/day to 950 ML/day. The flow downstream of Stevens Weir has averaged around 1,500 ML/day over the past week, but will be increasing over coming days to around 2,100 ML/day as increased flow is passed into the Edward River from the Edward Escape. Flow down Colligen Creek, which comes off Stevens Weir pool, was raised to around 650 ML/day following rainfall last week and is now being gradually lowered back towards 200 ML/day. Environmental water has been provided by NSW Office of Environment and Heritage to enable this gradual recession, which is similar to how the creek would have responded following rain under natural conditions. Figure 2 – Rice crop near Deniliquin earlier in the season (image taken in November). Photo: Alisha Caldwell, MDBA. On the Goulburn River, the flow at McCoys Bridge is 2,650 ML/day as a combination of environmental and inter-valley transfer (IVT) water is delivered into the Murray. This flow is planned to recede to approximately 1,000 ML/day by late January, then remain steady during the first week of February. At Torrumbarry Weir, diversions at National Channel are 2,000 ML/day. The flow downstream of Torrumbarry is 7,600 ML/day and forecast to remain around 7-8,000 ML/day over the coming week. The flow in the Murrumbidgee River at Balranald rose this week from 1,650 ML/day to 1,900 ML/day following recent rainfall which added to IVT water already en-route to the Murray. The flow at Balranald is expected to gradually reduce over coming weeks towards 180 ML/day, which is the usual end-of- system target for February. GPO Box 1801 Canberra ACT 2601 Telephone: 02 6279 0100 Facsimile: 02 6248 8053 Email: [email protected] Web: www.mdba.gov.au ABN 13679821382 Page 3 of 9 At Euston Weir, the flow is currently at a peak of around 11,000 ML/day due to a pulse of water released from the Goulburn River earlier in the month. At Menindee Lakes, the storage volume has decreased 18 GL to 156 GL (9% capacity). Releases at Weir 32 are steady at 150 ML/day, whilst local rain on the lower Darling last week has contributed to boosting the flow at Burtundy to 160 ML/day. At Wentworth Weir, the release is 9,000 ML/day and forecast to remain above 8,500 ML/day over the coming week. The weir pools at Locks 8 and 9 are gradually being lowered below their full supply levels and more information on the changing weir pool heights is available on the MDBA website. Due to essential maintenance work, navigation via the Lock 7 lock chamber will be unavailable from Tuesday 27 January for 10 to 12 weeks (see attached media release). The lock chamber will be de- watered during this time and boat users will be unable to pass through the lock. At Lake Victoria, the storage volume has decreased by 11 GL to 462 GL (68% capacity). The flow to South Australia was increased this week from 7,500 ML/day to around 10,000 ML/day. These increased flows are a result of additional environmental water made available to sustain higher barrage outflows into the Coorong. At the Lower Lakes, the 5-day average water level in Lake Alexandrina increased this week from 0.63 to 0.64 m AHD. Following improvements to the Lower Lakes water level over the past fortnight, barrage releases were increased towards the end of this week from 1,000 ML/day to around 2,000 ML/day. For media inquiries contact the Media Officer on 02 6279 0141 ANDREW REYNOLDS Acting Executive Director, River Management GPO Box 1801 Canberra ACT 2601 Telephone: 02 6279 0100 Facsimile: 02 6248 8053 Email: [email protected] Web: www.mdba.gov.au ABN 13679821382 Page 4 of 9 Water in Storage Week ending Wednesday 21 Jan 2015 Change in Full Current Total Full Supply Dead Active MDBA Storages Supply Storage Current Storage Storage Volume Storage Storage Level Level for the Week (m AHD) (GL) (m AHD) (GL) % (GL) (GL) (GL) Dartmouth Reservoir 486.00 3 856 474.72 3 159 82% 71 3 088 -26 Hume Reservoir 192.00 3 005 183.22 1 536 51% 23 1 513 -64 Lake Victoria 27.00 677 25.13 462 68% 100 362 -11 Menindee Lakes 1 731* 156 9% (- -) # 0 -18 Total 9 269 5 313 57% - - 4 963 -118 Total Active MDBA Storage 59% ^ Major State Storages Burrinjuck Reservoir 1 026 584 57% 3 581 -11 Blowering Reservoir 1 631 542 33% 24 518 +17 Eildon Reservoir 3 334 2 479 74% 100 2 379 -30 * 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 20 Jan 2015 Active Storage Weekly Change From 1 May Storage Diversion (GL) This Week (GL) (GL) 2014 Lake Eucumbene - Total 2 278 +3 Snowy-Murray +3 215 Snowy-Murray Component 1 134 +15 Tooma-Tumut +2 196 Target Storage 1 520 Net Diversion 1 20 Murray 1 Release +2 464 Major Diversions from Murray and Lower Darling (GL) * From 1 July From 1 New South Wales This Week Victoria This Week 2014 July 2014 Murray Irrig. Ltd (Net) 21.2 548 Yarrawonga Main Channel (net) 4.3 176 Wakool Sys Allowance 2.4 37 Torrumbarry System + Nyah (net) 9.2 393 Western Murray Irrigation 0.5 15 Sunraysia Pumped Districts 1.7 68 Licensed Pumps 5.0 163 Licensed pumps - GMW (Nyah+u/s) 4.3 43 Lower Darling 1.5 45 Licensed pumps - LMW 20 180 TOTAL 30.6 808 TOTAL 39.5 860 * Figures derived from estimates and monthly data.