There's now a 60 per cent risk of spill for Lake Hume, following good rainfall increasing flows into the Murray storage.
In the Murray Goulburn and Campaspe systems, entitlement holders can carry over up ot 100pc of their high and low-reliability water shares.
When seasonal determinations are higher than zero pc, holders may have more than their total HRWS and LRWS volume.
The water share volume above the HRWS and LWRS is quarantined in a spillable water account and may be lost if storages fill and overflow.
Northern Victoria Resource Manager Dr Mark Bailey said storage levels had risen, after rainfall and the end of the 2019-20 irrigation season.
"Rainfall over the last two months has increased the flows into the Murray, Goulburn and Campaspe storages," Dr Bailey said.
"The improved storage volumes warranted an update on the risk of spill in each system to help entitlement holders plan their portfolios for 2020/21.
"Victoria's share of the volume in Lake Hume gives the Murray system about a 60 per cent risk of spill."
The risk of spill from Lake Eildon in the Goulburn system now stood about 20pc, while for Lake Eppalock in the Campaspe system, it was about 50 per cent.
Dr Bailey said the risk of spill assessment did not describe the chances of flooding in the Murray, Goulburn or Campaspe systems this season.
"The risk of spill is a water accounting assessment. It does not refer to flood risks downstream of the storages," Dr Bailey said.
In the event of a spill, the Resource Manager deducts a proportion of all the spillable water accounts, based on the volume flowing out of the storages.
In the Murray, Goulburn and Campaspe systems, entitlement holders are able to carry over a volume up to 100per cent of their high and low-reliability water shares.
This may mean that when seasonal determinations are greater than 0pc entitlement holders may have more than their total high and low-reliability water share volume in a given season.
If this happens, then the volume above the high and low-reliability water share volume is quarantined in a spillable water account and may be lost if the storage in those systems fills and spills.
The Resource Manager conducts an assessment about the chances of the storages spilling in these systems ( Lake Hume, Lake Eildon and Lake Eppalock) on the 10th of each month.
If the chance is less than 10pc a low risk of spill will be declared and the water in the spillable accounts is returned to the allocation accounts.
The risk of spill in the Murray, Goulburn and Campaspe systems in 2020/21 will be updated on Wednesday July 1.
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