Lake Eyre Basin Rivers 166 economic value. Values for the Coorong wetland were estimated separately, given its significant economic value, with an improvement from poor to good quality estimated to deliver $4.3 billion in non-use value (MacDonald et al. 2011). The Centre for International Economics (2011) subsequently estimated the economic value of environmental benefits from the Murray–Darling Basin Plan. In this cost–benefit analysis, values were included only for changes in native fish populations, the frequency of waterbird breeding and the state of the Coorong, Lower Lakes and Murray Mouth (Fig. 18.2) because of a lack of ecological response data for the other ecological attributes. Aggregate value estimates (net present benefit) were $3750 million for a 3000 GL/year reallocation, $4760 million for a 3500 GL/year reallocation, and $5430 million for a 4000 GL/year reallocation of irrigation water to the environment, excluding an improved Coorong, which increased the overall estimate to $9704 million. Improvement in the state of the Coorong (from poor to good) was expected to occur only for the 4000 GL/year reallocation. Sensitivity analyses were done, including using alternative value estimates (Van Bueren and Bennett 2004) and a meta-analysis (Rolfe and Brouwer 2011). Overnight visitor numbers were respectively estimated to increase for different scenarios of returning annual environmental flows to the Murray–Darling Basin: 113 452 for 3000 GL/year, 133 463 for 3500 GL/year and 153 212 for 4000 GL/year. These changes in visitation were combined with value estimate of $585 per overnight trip to derive the aggregate change in recreation value. Other estimates were derived for changes in costs associated with salinity, flooding and dredging. As a result, it was possible to estimate the Fig. 18.2. The Coorong, Lower Lakes and Murray Mouth are listed as a wetland of international importance with environmental values, with significant economic values (Tables 18.5 and 18.6).
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