Northern Victorian resource manager Mark Bailey says the risk of spills is greater now than it has been for this time of year over the past few seasons.
He said entitlement holders should consider this when making decisions about how to hold any unused water, and plan for the new water year.
After three years of very dry conditions, dam levels are rising due to recent rainfall and the end of the irrigation season.
The risk of spill is now 60 per cent for Lake Hume (Murray) and 20 per cent for Lake Eildon (Goulburn).
Carryover rules give entitlement holders the flexibility to choose when to use or trade their allocations, and make use of dam storage space when it is available.
Spill rules are in place to free up space in the dams when it is needed to capture inflows that support increased allocations for entitlement holders.
Entitlement holders can carry over their unused water from one year to the next, against their high and low-reliability entitlements, and water that is carried over can be used or traded in the new water year.
Any water that is stored above full entitlement volumes is spillable and recorded in spillable accounts, and can only be used or traded once the resource manager makes a declaration that the risk of spill over the remainder of the season is less than 10 per cent.
If spills occur, these are applied proportionally to all entitlement holders storing more water than their full entitlement.
The next update on spill risks will be on July 1, when the first seasonal determinations for 2020-21 are made.
For more information on carryover and spill rules in Victoria, including a carryover calculator, visit: https://waterregister.vic.gov.au/water-entitlements/carryover/carryover-rules
For information on seasonal determinations for northern Victoria, visit: https://nvrm.net.au/outlooks/current-outlook
For information on spill risk for major storages in northern Victoria, visit: https://nvrm.net.au/risk-of-spill