measured by the average outflow at the Coorong are maintained. Under this
policy, adjustment to reduced inflows is achieved primarily through reduced
water use in agriculture.
Results
Simulation results for the expected values of four key variables are presented in
Table 2. These variables are: “Economic return”, that is, the total economic
return to agricultural and urban water use; ‘Salinity’ measured in EC units for
water supplied to Adelaide; ‘Water use’, measured in gigalitres (GL) and
including water used for irrigation and urban water supply; and ‘Environmental
flow’, measured in gigalitres as the outflow at the Coorong.
Table 2:Projections of key model variables
|
Simulation |
Year |
Economic |
Salinity |
Water use (GL) |
Environ- |
|
Baseline_________________ |
2000 |
2,739.3 |
460.0 |
11,869.9 |
4,774.5 |
|
Adaptation only |
2050 |
2,004.7 |
554.9 |
7,360.2 |
1,923.8 |
|
2100 |
1,042.0 |
NA* |
2,861.2 |
682.4 | |
|
Mitigation and adaptation |
2050 |
2,678.4 |
688.3 |
11,201.1 |
2,954.8 |
|
(Environment residual) |
2100 |
2,663.5 |
698.4 |
11,035.7 |
2,861.7 |
|
Mitigation and adaptation |
2050 |
2,443.8 |
359.2 |
8,378.2 |
4,864.0 |
|
(Environment priority) |
2100 |
2,413.6 |
349.9 |
8,070.8 |
4,869.5 |
* No meaningful average as there is zero flow in drought state
A number of features of these results are noteworthy.
First, although the volume of water available for use and environmental flows
falls significantly in all projections, the change in economic value from the
baseline simulation is similar, and relatively modest, for all the 2050
19