THE first 2025-2026 seasonal irrigation water determinations, together with updated determination outlooks and the initial risk of spill assessment for the Murray, Goulburn and Campaspe systems.
The Murray system starts with a seasonal determination of 39 per cent of high-reliability water shares (HRWS). The Goulburn and Loddon systems begin with 31 per cent HRWS.
The Campaspe system starts with 100 per cent HRWS. The Broken and Bullarook systems both start the year with 0 per cent HRWS.
Resource manager Mark Bailey said the opening seasonal determinations were lower than recent years, except in the Campaspe system.
“Drier conditions through 2024-2025 meant we had fewer reserves for the opening seasonal determinations compared to the last few years,” Dr Bailey said. 
“The Campaspe system was the exception and secured enough reserves for a 100 per cent seasonal determination,” he said.
“More water is needed in the Broken and Bullarook systems before seasonal determinations can increase.
“Recent rainfall in the catchment areas is welcome, but continued rainfall is needed over the coming months to increase storages levels and seasonal determinations across all systems.
“With below-average storage flows during May and June, the risks of spill have decreased since the last update was released in May 2025.
“The spill risk in both the Murray and the Campaspe systems is 40 per cent. In the Goulburn system, the risk of spill from Lake Eildon is about 25 per cent.:
Dr Bailey said the risk of spill assessment did not describe the chances of flooding this season. 
“The risk of spill is a water accounting assessment. It does not refer to flood risks downstream of the storages.”
On trading opportunities, allocation trade from New South Wales to Victoria is limited to the lesser of a net annual volume of 200 GL or a volume that keeps the risk of spill in Victoria’s share of both Hume and Dartmouth reservoirs below 50 per cent. The current risk of spill from Victoria’s share of Hume and Dartmouth allows 200 GL of allocation trade from New South Wales to Victoria.