The Resource Manager for northern Victorian water systems today updated the outlook for 2020/21 seasonal determinations and risk of spill.
Northern Victorian Resource Manager Mark Bailey said recent rain and an increase in water availability had improved the outlook for seasonal determinations against high-reliability water shares (HRWS) at the start of the 2020/21 water year.
"Flows into the major storages since the start of April provided a welcome increase in water availability," Dr　Bailey said. "Several storages received their highest April inflows in over 30 years.
"There is now enough resource available to meet operating needs in all systems and deliver seasonal determinations in the Murray, Goulburn, Campaspe and Loddon systems on July 1, 2020," Dr Bailey said.
"A repeat of the flows into the major storages observed in 2019/20 would result in the Goulburn system reaching about 85 per cent HRWS in February 2021 and the Murray system reaching about 60 per cent.
"Early season announcements in the Broken and Bullarook systems will be influenced by the volumes carried over and the flows into the storages between now and the end of June.
"Carryover will be deliverable in all systems throughout 2020/21.
"The flows and improved storage levels have increased the risk of spill in 2020/21. Based on flow records and recent flow trends, the current risk of spill in the Goulburn system during 2020/21 is estimated to be about 20 per cent. The risk in the Murray system has increased to about 50 per cent. The risk in the Campaspe system is also about 50 per cent."
Dr Bailey noted the Bureau of Meteorology climate outlook for June to August favours wetter than average conditions across all of northern Victoria.
"Customers may wish to factor the rainfall outlook and the risk of spill information into their plans for 2020/21 and the remaining weeks of 2019/20."
Further detail on outlook for the 2020/21 season
The outlooks for 2020/21 seasonal determinations are based on historical flow records that have been adjusted to match climate conditions observed since 1975. The outlook scenarios presented are:
Wet: Inflow volumes to major storages that are greater in 10 years out of 100
Average: Inflow volumes to major storages that are greater in 50 years out of 100
Dry: Inflow volumes to major storages that are greater in 90 years out of 100
Extreme Dry: Inflow volumes to major storages that are greater in 99 years out of 100
The following tables summarise the estimated high-reliability water share seasonal determinations through the season for each scenario in the Murray, Goulburn, Loddon, Campaspe, Broken and Bullarook systems.
Murray System Outlook for Seasonal Determination of High-Reliability Water Shares
| Wet |
13% |
49% |
100% |
100% |
| Average |
8% |
32% |
57% |
100% |
| Dry |
3% |
18% |
37% |
53% |
| Extreme Dry |
3% |
9% |
9% |
16% |
Goulburn and Loddon System Outlook for Seasonal Determination of High-Reliability Water Shares
| Wet |
41% |
76% |
100% |
100% |
| Average |
27% |
44% |
79% |
100% |
| Dry |
20% |
32% |
44% |
56% |
| Extreme Dry |
19% |
23% |
28% |
33% |
Campaspe System Outlook for Seasonal Determination of High-Reliability Water Shares
| Wet |
76% |
100% |
100% |
100% |
| Average |
21% |
40% |
100% |
100% |
| Dry |
5% |
8% |
19% |
32% |
| Extreme Dry |
5% |
5% |
5% |
0% |
Broken System Outlook for Seasonal Determination of High-Reliability Water Shares
| Wet |
65% |
79% |
100% |
100% |
| Average |
0% |
49% |
100% |
100% |
| Dry |
0% |
0% |
12% |
32% |
| Extreme Dry |
0% |
0% |
0% |
0% |
Bullarook System Outlook for Seasonal Determination of High-Reliability Water Shares
| Wet |
91% |
100% |
100% |
100% |
| Average |
0% |
100% |
100% |
100% |
| Dry |
0% |
10% |
94% |
100% |
| Extreme Dry |
0% |
0% |
0% |
0% |
Additional outlook scenarios for each system are available from the Northern Victorian Resource Manager website ( www.nvrm.net.au/outlooks ).
Outlooks for low-reliability water shares (LRWS) will be prepared during the 2020/21 season if seasonal determination are 100% HRWS and there is the possibility of LRWS being allocated.
Upcoming Resource Manager announcements
- The risk of spill in the Murray, Goulburn and Campaspe systems will be updated on Wednesday 10 June 2020.
- The first 2020/21 seasonal determination announcement will be released on Wednesday 1 July 2020 and will include an assessment of the risk of spill in the Murray, Goulburn and Campaspe systems and an updated outlook.