Lake Eyre Basin Rivers 168 Basin Plan (Prosser et al. 2012). This involved consideration of the return of 2800 GL/year of environmental water, less reallocation than previously modelled but close to the final provision in the Murray–Darling Basin Plan (2750 GL/year). They identified a wide range of ecosystem services benefiting from increased environmental flows (Table 18.6). Carbon sequestration was one of the large-valued ecosystem services (Table 18.6). Other values of erosion prevention and household salinity were smaller. There were also substantial changes to amenity value, with property prices near Barmah–Millewa Forest, the Lower Darling river system, the Mid- Murrumbidgee River Wetlands and Lake Alexandrina increasing overall by $353 million, due to increased river flows. Increased values for tourism were identified, with more flows along the River Murray adding $161 million/year (Table 18.6) to the present value of $490–649 million, previously calculated (Centre for International Economics 2011). Substantial use values were either excluded or underestimated in the first cost–benefit analysis of the Murray–Darling Basin Plan (Centre for International Economics 2011), compared to the subsequent estimates (Prosser et al. 2012), which included values for carbon sequestration, changes in property prices and recreation (Table 18.6). Neither study aggregated the individual value estimates produced across the Murray– Darling Basin. Using Prosser et al. 2012, this would have produced an estimated Table 18.6. Estimates of economic value of ecosystem services in the Murray–Darling Basin in response to improved flows in the rivers with 2800 GL/year of water reallocated from irrigated agriculture to the environment (Prosser et al. 2012). Ecosystem service Estimated value ($x million) Descriptiona Carbon sequestration 126–1041 Present value Erosion prevention 23.8 Present value Reduced household costs from salinity 3.1 Annual Reduced agricultural costs from salinity 29 Annual Recreation benefits from reduced blackwater events 5–10 Annual Reduction in acid sulphate soil 9.2 Annual Reduction in costs of dredging the Murray Mouth 3.6 Annual Increased property prices 311 (Coorong, Lower Lakes and Murray Mouth) 15.5 (Lower Darling river system) 1.3 (Barmah–Millewa Forest) Present value Tourism on the River Murray 161 Annual Non-use valuesb $7.7 billion (return of 2800 GL/year, including the Coorong) $3.4 billion (return of 2800 GL/year, excluding the Coorong) $3.9 billion scenario 3 (return of 2800 GL/year, with values for the Coorong adjusted by ecosystem state) Present value a ‘Present value’ refers to the current value of the future stream of benefits. ‘Annual value’ refers to the value of the benefits that will occur each year. b Increased value from native vegetation, native fish populations and frequency of waterbird breeding, and improved quality of the Coorong.
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