Outlook comparison

15 November 2018 Outlook for the 2018/2019 Season

The Resource Manager has used historical inflow records to determine seasonal determination outlooks. New guidelines recommend the use of climate behaviour post July 1975 to assess resource availability under the effects of climate change. During 2018/19, the Resource Manager is transitioning to the recommended climate behaviour for the seasonal determination outlooks.

A comparison of the seasonal determination outlooks using the revised characteristics and the full historical records for each system has been prepared for different inflow scenarios.

The scenarios for different inflow conditions were produced using the following terminology:

  • Wet: Inflow volumes to major storages that are greater in 10 years out of 100
  • Above Average: Inflow volumes to major storages that are greater in 30 years out of 100
  • Average: Inflow volumes to major storages that are greater in 50 years out of 100
  • Below Average: Inflow volumes to major storages that are greater in 70 years out of 100
  • Dry: Inflow volumes to major storages that are greater in 90 years out of 100
  • Very Dry: Inflow volumes to major storages that are greater in 95 years out of 100
  • Extreme Dry: Inflow volumes to major storages that are greater in 99 years out of 100

The following tables summarise possible HRWS seasonal determinations in the Murray, Goulburn, Loddon and Broken systems through the 2018/2019 season for the full range on inflow records and the climate adjusted inflow records based on post July 1975 climate behaviour.

The possible seasonal determinations for the Bullarook system are based on the full range of inflow records as there inflow records do not exist prior to 1975.

Murray System Outlook for 2018/2019 Seasonal Determination of High-Reliability Water Shares

  17 December 2018 15 February 2019
Inflow Conditions Full range Climate adjusted Full range Climate adjusted
Wet   100% 100%  100%   100%
Above Average   100% 100% 100%  100%
Average   100% 100%  100%  100%
Below Average   100% 100%  100%  100%
Dry   98% 91% 100%   100%
Very Dry  95% 87% 100% 96%
Extreme Dry  90% 85% 95%  88%

Goulburn and Loddon System Outlook for 2018/2019 Seasonal Determination of High-Reliability Water Shares

  17 December 2018 15 February 2019
Inflow Conditions Full range Climate adjusted Full range Climate adjusted
Wet   100%  100%  100%  100%
Above Average   100%  100%  100%  100%
Average   95% 100%  100%  100%
Below Average   91% 100%  99%  100%
Dry  88% 97% 93% 100%
Very Dry   87%  94% 91%  100%
Extreme Dry  86% 90%  88%  95%

Broken System Outlook for 2018/2019 Seasonal Determination of High-Reliability Water Shares

  17 December 2018 15 February 2019
Inflow Conditions Full range Climate adjusted Full range Climate adjusted
Wet   68%  50%  100%  100%
Above Average   42%  36%  96%  31%
Average   35%  45%  31%  49%
Below Average  31% 38%  29% 38%
Dry   23%  27%  22% 27%
Very Dry   21%  17% 20%  24%
Extreme Dry   19%  14% 19% 20%