Water Journal : Water Journal May 2013
37 Feature Article MAY 2013 WATER limitations in the Plan development and identify the ecological bene ts, risks and opportunities of the proposed water recovery scenario. In response to the breadth of knowledge and the short timeframes required to undertake this evaluation, the Goyder Institute established an Expert Panel comprising experts in the areas of riverine, oodplain and estuarine ecology from its partner institutions of the University of Adelaide, SARDI and CSIRO. No modelling was undertaken by the Goyder Institute or any members of the Expert Panel in relation to its evaluation of the Draft Basin Plan. Overall, the Expert Panel found that there were important bene ts identi ed under the Draft Basin Plan water recovery scenario of 2750GL, in particular increases in within-channel variations to stream ows that increased the ooding frequency and duration of low-elevation wetlands, and some improvement in the connectivity between the Lower Lakes and Coorong. However, for much of the medium to high elevations of the oodplains that require medium to high ows, the environmental water requirements were not met. In addition, the Coorong, Lower Lakes and Murray Mouth Ramsar site remained at risk from low water levels and high salinities during dry periods. The MDBA salt export target of two million tonnes per year on a 10-year rolling average was not met and constriction of the Murray Mouth would still occur, which would likely require dredging to keep it open during extended droughts. In the MDBA's own analysis of the oodplain, only 11 out of 18 of the MDBA environmental water requirements were achieved under this scenario (MDBA, 2012). The Expert Panel concluded that the ecological character of the South Australian environmental assets, as de ned in current water management plans, were unlikely to be maintained under the Draft Basin Plan water recovery scenario of 2750GL and recommended that the following issues should be taken into consideration in the nalisation of the Basin Plan: • Modelling of a wider range of possible water scenarios, including additional volumes of water for the environment and scenarios with relaxed operational and physical channel-capacity constraints; • Interventions to rehabilitate currently degraded assets to reduce the risk that the desired ecological character will continue to deteriorate prior to full compliance with Sustainable Diversion Limits; • Management of drought recovery of degraded assets following prolonged periods of low ows; WHAT'S IN A NAME? George Woodroffe Goyder (24 June 1826--2 November 1898) was a surveyor in South Australia during the latter half of the 19th century and was appointed Surveyor-General in 1861. George Goyder observed the difference in vegetation type as a result of rainfall gradients as he traversed the state. He used this to set a limit beyond which cropping would be unsustainable. His predictions were highly unpopular at the time, but he proved to be right. This line is now called 'Goyder's Line' and was an early example in South Australia of science being used to inform policy. Looking down onto the River Murray at Renmark, South Australia.
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