Water Week

EWN Publishing

Flow to South Australia slow: September 2007, Lowest flows since 1968, downstream of Euston Weir, and no flow at all from from Kiewa and Ovens

Posted by waterweek on 28 September 2007

The pattern of flows to South Australia over the remainder of the season will be critical in managing river salinity in SA and for meeting increasing diversion requirements and losses said David Dreverman General Manager in the River Murray Report For The Week Ending Wednesday, 19 September 2007.

Hot and dry: During the past week light rain (5-10 mm) fell over the south and north of the Murray-Darling Basin . The majority of rain was concentrated in northeast Victoria with Mt Buller and Thredbo receiving 20 mm and 17 mm respectively. The rain was sufficient to temporarily slow the decline in inows, particularly in the Ovens and Kiewa catchments. River Murray System inows totalled about 52 GL this week, well below the long term weekly average for September of around 380 GL.

No flow from Kiewa and Ovens: Due to the relatively dry and warm weather, the Kiewa and Ovens inows were now insufcient to meet all downstream requirements. As a result, Hume release was increased from 460 to 2 000 ML/day in order to supplement these inows. The flow at Doctors Point has increased from 1 200 to 3 500 ML/day (21st September).

Hume balance: Storage at Hume Reservoir continues to rise and was currently 840 GL (28 per cent capacity). Storage volume in Dartmouth was currently 660 GL (17 per cent capacity) and release remains steady at 200 ML/day. The level of Lake Mulwala has continued to be gradually lowered and was currently 123.75 m AHD, 115 cm below its full supply level (FSL). However, the level of the level of the lake was expected to be steady or slightly rise over the coming weeks due to the increased release from Hume Reservoir and a reduction in diversions at Mulwala Canal. Over the past few weeks, release from Yarrawonga was kept at very low levels of around 2400 ML/day.

Lowest flows since 1968: As a result, the flow downstream of Euston Weir has gradually fallen to 2100 ML/day and was expected to reduce to less than 2000 ML/day this weekend. These were the lowest ows experienced at this site since the drought of 1968 when release fell to 1800 ML/day. Mildura Weir was currently at 34.44 m AHD, 4 cm above FSL and Wentworth was 30.86 m AHD, 6 cm above full supply level. Both weirs were slightly above FSL in preparation to meet any increase in diversion requirements in Sunraysia whilst ow rates were very low.

Flow to South Australia: Release from Wentworth Weir was currently 2 300 ML/day and was expected to continue to fall next week. Lake Victoria storage peaked at 556 GL (82 per cent capacity) this week and has since decreased to 550 GL. Inow to Lake Victoria has remained steady at around 1200 ML/day and release from Lake Victoria has increased to 1400 ML/day. Flow to South Australia was increased to 2 000 ML/day as part of a program of ow increases over coming months.

David Dreverman General Manager. Report For The Week Ending Wednesday, 19 September 2007 51 Allara Street Canberra ACT GPO Box 409 Canberra ACT 2601 Switchboard 02-6279 0100; Weekly Report Enquiries 02-6279 0126, Facsimile 02-6230 6005 Internet : http://www.mdbc.gov.au

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