Northern Victorian Resource Manager releases 2020/21 seasonal determination outlook

The Resource Manager for northern Victorian water systems today released the first outlook for 2020/21 seasonal determinations.

Northern Victorian Resource Manager Mark Bailey said seasonal determinations against high-reliability water shares (HRWS) at the start of the 2020/21 water year would depend heavily on flows received into the major storages during autumn and early winter.

“After consecutive years of below-average inflows, stored resources are depleted. Resources available for 2020/21 in the Murray and Goulburn systems are limited to the early season reserves established when seasonal determinations were between 30 and 50 per cent HRWS. Without an increase in the storage volumes, opening seasonal determinations are likely to be low,” Dr Bailey said.

“A repeat of the flows into the major storages observed in 2019/20 would result in the Goulburn system reaching about 60 per cent HRWS in February 2021 and the Murray system would be about 45 per cent.”

“Seasonal determinations in the Loddon system are likely to be similar to the Goulburn system.

“Early season announcements in the Campaspe, Broken and Bullarook systems will be influenced by the volumes carried over and the catchment conditions. Each system is likely to start at zero per cent HRWS.

“Carryover will be deliverable under all scenarios in the Murray, Goulburn and Loddon systems. At this point, there is not enough water to operate the Campaspe, Broken and Bullarook systems as usual for the entire 2020/21 season. Carryover will be deliverable early in the season and will be extended as resource improvements occur.

“Resource improvements to July 2020 will improve the operating outlook.

“Based on assumed use to the end of 2019/20, allocation carried over into 2020/21 and climate-adjusted flow records, the risk of spill in the Goulburn system during 2020/21 is currently estimated to be less than 10 per cent. The risk in the Murray system is about 30 per cent. The Campaspe system currently has a 20 per cent risk.

“Customers may wish to factor this into their plans for the remaining months 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 possible high-reliability water share seasonal determinations this season and include a reference year to help users recognise the possible inflow conditions. 

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

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

Campaspe System Outlook for Seasonal Determination of High-Reliability Water Shares

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

Bullarook System Outlook for Seasonal Determination of High-Reliability Water Shares

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 next 2019/20 seasonal determination announcement will be released on Monday March 2, 2020.
• The 2020/21 seasonal determination outlooks will be updated on Friday May 15, 2020.
• The first 2020/21 seasonal determination announcement will be released on Wednesday July 1, 2020 and will include an assessment of the probability of spill in the Murray, Goulburn and Campaspe systems and an updated outlook.