Discussion Paper - Part A - Victorian Environmental Assessment ...

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Table 4.1 Meteorological data for major towns within and near the study area.LocationElevation(masl)Mean annual dailymax. temp. ( o C)Mean annual dailymin. temp ( o C)Mean annualrainfall (mm)Mean annual #of clear daysMildura5023.710.3289131Swan Hill7023.09.7349127Echuca9622.29.442893Kerang7822.89.4373125Bendigo20820.77.650299Tatura11421.28.3493110Benalla17022.08.7670125Wangaratta15021.98.8637113Wodonga15222.18.9715125Myrtleford22321.76.6905103Mt Hotham17509.52.3197953Melbourne3119.810.165349Notes: Data for Swan Hill, Wangaratta, Wodonga, Myrtleford, and Mt Hotham have been collected over various historic periods.Data from Melbourne and Mount Hotham have been included for comparison.Source: Bureau of Meteorology, data last modified 16/8/2004The report also found that rainfall has increased over thelast 50 years over northeastern Australia, but decreasedin the southwest of Western Australia and in much ofsoutheastern Australia, especially in winter. There werenear-record low water levels in much of southeasternAustralia’s water storages in 2002-03, and littleimprovement since. There is a substantial risk that thispattern will continue for several decades. Droughts havebecome hotter and more severe, and this trend isexpected to continue; tropical cyclones have becomemore intense and frequent; and heavy rainfall incidentshave become more frequent in many parts of Australia.Increased greenhouse gas concentrations and ozonedepletion may both be contributing to a strengtheningof the atmospheric winds over Antarctica, dragging rainaway from Australia and into the Southern Ocean(Pittock 2003).The AGO presents a general picture of the trends andpotential impacts of climate change in Australia butsignificant knowledge gaps still exist. However,observations clearly demonstrate that the climate isalready changing.Projections of Victoria’s Future ClimateThe Victorian Government commissioned CSIRO toundertake high-resolution regional climate changeprojections for Victoria in 2002 (Whetton et al. 2002).The projections are based on the results of climatemodelling in which the effect of increased levels ofgreenhouse gases in the atmosphere are simulated. Therange of regional climate change projections allows foruncertainty in future greenhouse gases increases, and fordifferences between the simulated climate change ofvarious climate models. These projections to 2070 werereviewed in 2004.In each decade since 1950, Victoria’s average maximumtemperature has increased 0.11ºC and average minimumtemperature has increased by 0.07ºC. When comparedto national trends, Victoria’s maximum temperatureappears to be changing at a faster rate, and ourminimum temperature at a slower rate (Whetton et al.2002). Whetton et al. (2002) predict that Victoria is likelyto be 0.7 to 5.0º C warmer than it was in 1990 with thefrequency of extreme maximum temperatures expectedto increase, with up to three times more hot days insome areas of the state. The frequency of frosts is alsolikely to decrease, with much of the state likely tobecome frost-free at the higher levels of projectedtemperature increases.This pattern of increasing temperatures is also apparentwithin the Murray-Darling Basin (see Figure 4.1).Discussion Paper33
Figure 4.1 Annual anomalies (based on 1961-1990 averages) of mean temperature in theMurray-Darling Basin.2Australian Bureau of MeteorologyMean Temperature Anomaly (∞C)10-1-21910 1920 1930 1940 1950 1960 1970 1980 1990 2000Source: Bureau of Meteorology (2006)Notes: The black line shows the 11-year moving average.Extreme rainfall events have increased in Victoria overthe past century, and evidence exists of severe droughtsduring strong El Niño years in northern and southernVictoria with an increasing tendency for more frequentEl Niño conditions over the past decade. Whetton et al.(Whetton et al. 2002) predicts that rainfall is likely todecrease, although there could be increases in someareas. Extreme daily rainfall events may become moreintense and more frequent in many regions. Projectedchanges in annual rainfall range from +10 to -25percent in most southern regions and +10 to -40percent in most northern regions of Victoria. Warmerconditions will increase evaporation which, combinedwith reduced rainfall, is likely to increase moisture stressand wildfire risk.Summaries of predicted climate change and impacts forcatchment management regions provide a detaileddiscussion of the available information and likely resultsof climate change (DSEa, b, c, d). Some tangibleexamples compare current climate with predicted 2070climate with a moderate greenhouse scenario of2ºdegree C warming and a 10 to 20 percent decrease inannual rainfall. Under these conditions in 2070,Wangaratta would have the current climate of Dubbo(New South Wales—NSW), while Bendigo would bemore like the current climate of Echuca. Mildura wouldbe expected to be more like Menindee (NSW), whileShepparton is expected to be more like the currentclimate of Condobolin (NSW).Water ResourcesThese predicted climate changes are likely to makeVictoria’s water resources increasingly vulnerable.Increased temperatures and evaporation rates will reducewater supply, affecting agriculture and biodiversity inparts of Australia. Demand for water is likely to increasewith warmer temperatures and increased evaporation,although his may be offset by increases in seasonalrainfall patterns. Conservation measures, behaviourchange and alternative supplies may also minimise theseimpacts.Climate change may reduce and increase variance inrainfall, reducing river flows and run-off (e.g. Jones et al.2002; Whetton et al. 2002; van Dijk et al. 2006).Preliminary results indicate that average annual run-offfor Victoria’s surface water management areas willreduce with climate change. In broad terms, the streamflow across the Murray-Darling Basin may be reduced by5 percent in 20 years (1100 GL) and up to 15 percent in50 years (van Dijk et al. 2006). In Victoria, a decline inrainfall is predicted to decrease run-off between 0 to 45percent in 29 Victorian catchments (Jones & Durack2005). Systems such as the upper Murray River couldhave up to 20 percent less run-off by 2030 and greaterthan 50 percent reductions by 2070. Such losses farexceed any savings currently required to provide forenvironmental water (see chapter 15) which have proveddifficult to achieve under current circumstances.Our need to use water more efficiently is likely to bereinforced by climate change. However, the predicted34 River Red Gum Forests Investigation 2006
Page 3 and 4: 2 GeologyGeology underpins the dive
Page 5 and 6: Figure 2.2 Schematic diagram of fol
Page 10 and 11: et al. 2000). This Selwyn Block is
Page 12 and 13: Figure 2.4 Murray Basin during the
Page 14 and 15: quartz sand and gravel beds, carbon
Page 17 and 18: Box 3.1 River MeandersRivers rarely
Page 19 and 20: lakes by flooding from Chalka Creek
Page 21 and 22: major valleys. The large, older fan
Page 23: ecommending representative areas fo
Page 26 and 27: Box 3.2 Barmah Area GeomorphologyTh
Page 28: 4 Climate andHydrological SystemsAu
Page 33: such as messmate have a thick prote
Page 36: Natural Hydrology of the River Murr
Page 39: Table 4.3 Stream flow in major Vict
Page 42 and 43: GroundwaterHydrology also relates t
Page 44 and 45: FloodplainsThe floodplains of the R
Page 46 and 47: 5 BiodiversityBiodiversity is impor
Page 48 and 49: Ecosystem Assessment 2005). Species
Page 51: Figure 5.2 Hairy darling-pea on a r
Page 57 and 58: Figure 5.5 A common blue-tongued li
Page 59: Threatened VertebratesBased on cons
Page 64 and 65: Figure 5.8 Mature river red gum on
Page 66 and 67: Figure 5.12 Tangled lignum at Mulcr
Page 68 and 69: Egrets generally only breed in livi
Page 70 and 71: which is essential habitat for some
Page 72 and 73: dependent species including darling
Page 74: Table 5.7 Summary of risk levels to
Page 77 and 78: Figure 5.22 Koala in a river red gu
Page 79 and 80:
Examples include the larvae of leaf
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Figure 5.27 Cattle on the bank of t
Page 83 and 84:
Table 5.8 Comments on fire from exp
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6 Indigenous LandAssociationsThis c
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Table 6.1 Summary of area in Victor
Page 91 and 92:
waters. The Joint Body is funded to
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Consultative ManagementConsultative
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7 Non-IndigenousHistoryThe resource
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Figure 7.2 Murray Downs homestead (
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Reception Centre established in 194
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and rural water supply became the r
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FisheriesThe collapse of the Murray
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