GMW customer service and operations head Daniel Irwin said it was expected demand for irrigation water would increase during autumn, traditionally a high use period.
“Our customers also have a significant portion of their water to use after this season’s positive allocations,” Mr Irwin said.
Rainfall received during the current irrigation season meant GMW had delivered only 427 gigalitres (GL), compared with a five year average of 864GL.
More than 900GL of irrigation water was still available to customers in the Goulburn Murray Irrigation District (GMID).
Mr Irwin said some channel congestion may occur, when demand for irrigation water increased.
“In instances where irrigation water demand exceeds channel delivery capacity for only a short period, we will schedule irrigation orders - linking start orders with finish orders,” Mr Irwin said.
“This means we are requesting that customers be flexible with start dates and times to fit demand within available capacity.
“In isolated locations, where irrigation water demand exceeds channel delivery capacity for an extended period, we may be required to implement a ration cycle. This ensures all customers receive a fair supply as we manage this congestion.”
Rationing meant GMW would be sharing the available delivery capacity.
For customers it could mean order start times and durations were changed.
Changes would be made based on a customer’s rate of delivery share, at a particular service point.
“If demand for water does not exceed our channel delivery capacity, there will be no change to order scheduling,” Mr Irwin said.
“To ensure we’re working as closely as possible with our customers to manage their water needs we’re encouraging them to contact their planner to discuss their autumn irrigation needs.
“With information on our customers planned irrigation needs we will be able to better balance supply for all customers.”
Meanwhile, a low risk of spill has been declared for the Murray system, in northern Victoria.
Northern Victorian resource manager Mark Bailey said the risk of spill in the Murray system, during 2016/17, was now below the 10 per cent threshold needed for a declaration.
"Based on Victoria’s share of the volume held in Lake Hume, the risk of spill is about 5 per cent," Dr Bailey said.
"Any water remaining in spillable water accounts in the Murray system will be made available to entitlement holders for use or trade."
Dr Bailey added the risk of spill assessment did not describe the chances of flooding in the Murray system.
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 the Murray system below 50 per cent. The current risk of spill limit allows 200 GL of net trade from New South Wales to Victoria.
The next announcement on the risk of spill and its effect on water availability will refer to the 2017/18 water year.
The first risk of spill assessment in the Murray, Goulburn and Campaspe systems for the 2017/18 season will be announced on July 3, 2017.