Cobon, David H.

Toombs, N. R.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings 21st International Grassland Congress / 8th International Rangeland Congress Impacts of Climate Change on Regulated and Non‐Regulated Water Systems in Australia David H. Cobon Queensland Climate Change Centre of Excellence, Australia N. R. Toombs Queensland Climate Change Centre of Excellence, Australia Follow this and additional works at: https://uknowledge.uky.edu/igc  Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/21/7-1/9 The 21st International Grassland Congress / 8th International Rangeland Congress took place in Hohhot, China from June 29 through July 5, 2008. Proceedings edited by Organizing Committee of 2008 IGC/IRC Conference Published by Guangdong People's Publishing House This Event is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in International Grassland Congress Proceedings by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. 瞯 ]826　 瞯 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅰ 　Grasslands/Rangelands Resources and Ecology ———Water Resources in Grasslands/RangelandsImpacts of climate change on regulated and non‐regulated water systems in AustraliaCobon , D .H .and Toombs , N .R .Queensland Climate Change Centre o f Excellence , EPA , 203 Tor St .Toowoomba , Q 4350 , A ustraliaE‐mail : Dav id .Cobon＠ climatechange .qld .gov .auKey words :Cooper Creek , QMDB , flowsIntroduction The highly regulated system of the Queensland Murray Darling Basin ( QMDB) includes the MacIntyre Brook andDumaresq River .Land‐use is irrigated horticulture , dryland and irrigated cropping and grazing .The largely unregulated systemof the Cooper Creek drains into Lake Eyre and land‐use is primarily grazing .Both systems have valuable natural resources andbiodiversity that rely on periodic flooding .This study identified the impact of climate change of water flows in both catchments .Material and methods From a combination of nine Global Circulation Models ( GCM摧s) and emission scenarios ( SRES and IS９２a)obtained from the OzClim database ( CSIRO , ２００１ ) , the driest , wettest and average scenarios were chosen for bothcatchments .Percentage changes from the base climate ( １９６１‐１９９０ ) were used to condition rainfall and evaporation for ２０３０ .Rainfall‐runoff ( Sacramento ) and streamflow ( IQQM ) models for each catchment were run for the base and climate changescenarios ( dry , wet , average) to obtain flows at the end‐of‐system for the MacIntrye Brook and Dumaresq River , and atCurrareva ( junction of the Thomson and Barcoo Rivers) in the Cooper Creek system .Results and discussion Based on these scenarios the change in mean annual flow for the MacIntyre Brook ranged from ‐２５％ to ＋９％ by ２０３０ , compared to the base period ( Table １ ) .For the Dumaresq River the change in mean annual flow ranged from ‐２５％ to ＋ ６％ by ２０３０ .The dry scenario was associated with a greater risk of lower water allocations and area of crops plantedduring dry periods .The change in mean annual flow at Currareva ranged from ‐７％ to ＋ ２％ by ２０３０ , compared to the base period ( Table １) .Theaverage and dry scenarios were associated with a reduced frequency of low daily flows ( ＜ １０００ ML /d) .The impact maybeassociated with reduced waterhole persistence and connectivity during periods of drought .Conclusion The climate change scenarios used here showed that the regulated system had １ ) higher reductions in flows for thedry scenario and ２) a wider range of uncertainity in flow projections compared to the unregulated system .If the dry scenariomost closely resembles climate in ２０３０ the loss of water for irrigators and environmental flows in the absence of useful adaptivestrategies may reduce agricultural productivity and biodiversity .The resilience of plant and animal life that depend on waterholesduring periods of drought may depend on their ability to move to larger and more permanent waterholes .If the wet scenariomost closely resembles climate in ２０３０ slightly higher annual flows may make more water available .The average changes inflows reported here for QMDC correspond closely with the best estimate of climate change in ２０３０ of １０％ reduction in surfacewater availability ( CSIRO ２００７) .Table 1 Percentage change in mean annual stream f low the f or dry , average and wet climate change scenarios in ２０３０compared to the base period o f １９６１‐１９９０ .Catchment Dry scenario Average scenario Wet scenarioMacIntyre Brook ‐QMDB ‐２５  ‐９ !＋ ９ �Dumaresq River ‐QMDB ‐２５  ‐１０ 8＋ ６ �Thomson and Barcoo River junction at Currareva ‐７ 镲‐４ !＋ ２ �ReferencesCSIRO , ２００１ .Climate Change Projections for Australia .Division of Atmospheric Research CSIRO , Aspendale .CSIRO , ２００７ .Water availability in the Border Rivers .A report to the Australian Government from the CSIRO Murray‐DarlingBasin Sustainable Yields Project , CSIRO , Australia .１４４pp .

Impacts of Climate Change on Regulated and Non‐Regulated Water Systems in Australia

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Impacts of Climate Change on Regulated and Non‐Regulated Water Systems in Australia

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