Dry Seasonal Conditions in Rural Victoria
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Department of Primary Industries Dry Seasonal Conditions in Rural Victoria Report: 63 February 8, 2007 DPI staff supporting the community at a Mallee Drought Information Expo. (February 2007). Source: L. Jacka Environmental Indicators Weather Rainfall December 2006 had below average rainfall across the state with parts of the south west and east of the state receiving well below average rainfall. A significant area of the north east had the driest December on record (Figure 1). 2006 was a very dry year in south east Australia, with a number of places receiving record low annual totals and a number of other places receiving less than half their usual rainfall. The year will be remembered for being the 10 th consecutive year with below normal rainfall. It was the third driest year on record for Victoria. This is in marked contrast to the north and west of Australia where rainfall was well above average. In January 2007 the west of the state received above average totals while the east of the state was below average (Figure 2). Most of the rain fell between the 19 th and the 22 nd . The highest rainfall total recorded for the month was Casterton Showgrounds with 172 mm. DSC Report 1 Figure 1. Victorian rainfall deciles 1 month (December 2006) National Climate Centre Bureau of Meteorology Figure 2. Victorian rainfall deciles 1 month (January 2007) National Climate Centre Bureau of Meteorology Temperature In December 2006 day time temperatures were generally 1-2ºC above average and nights were 1-3ºC below average. A cold burst from Dec 24 th produced cold conditions for the Christmas period and snow was reported in some regions of the state. In 2006 Victorian day time temperatures averaged mostly about a degree above normal, whilst night time temperatures averaged about half a degree below normal. There were some severe frosts during the year. In Melbourne, there were some notable individual extremes - for example, the earliest 30+ degree day in spring, the earliest 35+ degree day in spring, and the coldest Christmas Day on record. Australia-wide it was the 11 th warmest year since records started in 1910. In January 2007 nights were 1-2ºC above average across the state. Temperatures during the day were above average in January, more so in the east. Seasonal outlook The Bureau of Meteorology’s Seasonal Outlook (Jan 23 rd ) shows a moderate shift in the odds towards above average falls in western Victoria and also along parts of the central coast (Figure 1). The probability of exceeding median rainfall is 60-65%, however the outlook has low skill for this time of year. The temperature outlook for the February to April period shows that below average maximum temperatures are favoured over the western half of Victoria. The Southern Oscillation Index for December was -3 and for January was -7. The neutral SOI is one of a few indicators which show that the current Pacific El Niño pattern is beginning to weaken. DSC Report 2 Water storages Goulburn-Murray Water (G-MW) On Dec 22 nd G-MW confirmed that further improvements in water resources would be directed into allocation improvements rather than season extension. On Dec 16 th they increased water allocations by 1% at Goulburn (up to 24%) and Broken (up to 66%). On Jan 15 th they increased the Broken by 5% (up to 71%). Distribution losses in the Murray System have meant that the end of the irrigation season will be brought forward to April 23 rd in the Torrumbarry System and to April 30 th in the Murray Valley system. The season usually ends on May 15 th . Pending Ministerial approval, G-MW also expect to release an additional 7,000 ML of environmental water for sale into the Goulburn System. It is anticipated that this will be released later in February and the release will be staged over a month. Southern Rural Water (SRW) Lake Glenmaggie held just 12.8% of capacity at the end of December which is the lowest storage figure recorded at this time in the last 30 years. Macalister irrigation allocations remain on 45% for the Northern, Eastern and Tinamba/Riverslea areas. However, on Dec 19 th SRW increased the allocations for those below the Cowwarr Weir (Thomson River, Rainbow Creek and Nambrok Denison) by 5% (up to 50%). These irrigators are able to access water from the Thomson River. Storage Change in Capacity Storage Change in Capacity last 2 months 6/02/07 last 2 months 6/02/07 Goulburn Basin -5% 12% Thomson/ LaTrobe Basin -8% 26% Broken Basin -8% 17% Werribee Basin -3% 11% Campaspe Basin -2% 3% Glenelg/ Wimmera Basin -1% 5% Loddon Basin -2% 21% Maribyrnong -1% 5% Upper Murray Basin -10% 16% Barwon Storage -5% 24% Ovens Basin -28% 34% Source: http://www.fishvictoria.com/pnews/water_levels.php Victoria’s rural storages ended 2006 at 17.6% of capacity, 31.5% lower than last year. Streamflows At the end of December 2006, over 80% of the state had streamflows that were below 10% of the long term average flow for the month. At nearly two-thirds of the gauged stations the flows were the minimum ever recorded during December. More than half the stations recorded no flows by the end of December. In January 2007 the River Murray System recorded the lowest inflow on record for the 8 th consecutive month. The primary catchment area in the east received average to below-average rainfall in January. Water management Federal Government $10 billion water plan On January 25 th the Prime Minister announced a $10 billion, 10 point plan on a national scale to improve water efficiency and to address the over-allocation of water in rural Australia, particularly in the Murray-Darling Basin. Victorian changes New permanent trading rules (18 Dec 2006) will require a seller's allocation of water to be at least equal to the allocation levels that apply in the buyer's system, protecting other users in the system receiving the traded water. Under the previous rules, if 100 ML of Goulburn entitlement (24% allocation) was permanently traded to the Victorian Murray system (95% allocation), the buyer received 95 ML of allocation in the current season, while the seller only held 24 ML of allocation. The shortfall of 71 ML affects all users. Sellers can ‘top up’ their water prior to transfer or buyers can elect to surrender the shortfall volume. Permanent interstate water trade between Victoria and New South Wales will commence on 1 January 2007. Access fees and termination fees will be calculated and implemented by 1 July 2007 and exit fees will also be removed by this date. Up until removal of exit fees, they may be avoided by buyers and sellers contracting to use temporary trade processes followed by a permanent transfer. The Department of Sustainability and Environment and water authorities are consulting with irrigators, other water users and environment groups about a proposal to allow carryover of water to next season in the Murray and Goulburn systems. Under current arrangements, water that isn’t used at the end of the season goes back in a communal pool for the whole system. DSC Report 3 A plan to bypass the Barmah Choke to allow faster delivery of irrigation water is likely to be supported by the federal government’s $10 billion water plan. This would allow unrestricted trade from upstream to downstream of the Choke and allow water to be more easily traded between the Murray and Goulburn systems. The Choke currently limits the amount of water available downstream during periods of high flow. Fire The number of fires to January 7 th is 655 compared to the 30-year average of 401. The area burnt is 1,189,279 ha or more than 11 times the 30-year average. The large Gippsland / North East fires which commenced on December 1 st , 2006 have burnt over 1 million hectares. The Great Divide Complex North fire burnt 370,000 ha and is contained. The Great Divide Complex South fire burnt 677,000 ha and is contained. The Tatong fire burnt 31,000 ha and is under control. Losses to Jan 31 st include 51 houses, 1,700 livestock, 17,000 ha of pasture and crops, and 1,800 km of fencing. Fisheries Goulburn-Murray Water (G-MW) plans to pump down Lake Buffalo in order to maintain the water supply for the Ovens Valley. While some deep pools will remain as a fish refuge, rain events may mobilise sediments leading to poor water quality. DPI is considering issues such as how to manage fishing while low water levels prevail, and how best to ensure recovery of fish stocks once conditions return to normal. Lake William Hovell and Lake Nillahcootie are likely to be drawn down to low levels by the end of the irrigation season. Water is also being pumped from Coliban Reservoir to the adjacent Lauriston Reservoir. This places greater pressures on fish stocks remaining within these water bodies and innovative measures are required for their protection and management. Fires have caused increased sedimentation due to accelerated erosion and ash deposits in many parts of the state. Poor water quality can place additional stress on fish already suffering from summer temperatures and low water levels. Social Indicators DPI Drought Hotline The DPI / DSE Customer Service Centre received 383 drought related contacts for December 2006 and 343 for January 2007, compared to 628 in November 2006. Over December and January enquiries were from the South West (246), North West (154), North East (127), Port Phillip (91), Gippsland (43), interstate (20) and unknown (45).