For Murrumbidgee Valley irrigators, groundwater has been a drought-proof water source.
But four years of above average take from bores has caught up, and the NSW Department of Industry has announced Lower Murrumbidgee groundwater allocation will be restricted next water year.
The NSW Groundwater Allocation Statement explained water sharing plans allowed groundwater to be temporarily pumped for some years at higher volumes than the annual limit.
"This provides some operational flexibility to respond to variations in climate conditions, including droughts," it stated.
"However, the plans also set limits on the period that this higher level of extraction can continue.
"To prevent unacceptable resource depletion, once this compliance trigger is reached, groundwater allocations are reduced until the extraction is back within the plan's annual limit."
The extraction limit for the Lower Murrumbidgee groundwater source is 270,000 megalitres per year. Extraction for this water year is currently at 316,414ML.
Gavin Dal Broi irrigates at Warrawidgee, near Griffith. He said the announcement had made them re-evaluate hisr future planning, which relied heavily on the secure availability of bore water.
"In the past, it's always been a given that it's (groundwater) been a 100 per cent allocation," he said.
"We have one farm which is solely irrigated by groundwater, it was our drought-proof farm, it kept the wheels turning during the drought, kept us farming and investing.
"So this is definitely going to hurt our operation, our cropping program may be reduced by 50pc due to the changing risk profile.
"We've already brought our summer cropping back because we expected restrictions last year. We were very close to breaking the cap, but we ended up just under."
Riverina cotton reliant on groundwater
Mr Dal Broi explained for crops like cotton, a secure water source like groundwater was crucial as they forward sold years in advance.
"We can't rely on farming a month after they give us the allocation, because we need to sell cotton two years out," Mr Dal Broi said.
"At the moment we only ever sell on our bore water area."
Southern Cotton chief executive officer Kate O'Callaghan said nearly the entire Riverina cotton crop had been grown on bore water this year.
"Any restriction on our most valuable input is obviously a concern," Ms O'Callaghan said.
Three-year average changes to five years
How much groundwater will be restricted in the Murrumbidgee Valley is still being calculated.
What growers do know, is that the annual average extraction (which the restrictions are based on) will now be calculated over a five year period instead of a three year period due to a change in the new Water Sharing Plan for the valley, which comes into effect on July 1.
Darlington Point irrigator Matt Toscan, who has been almost entirely reliant on groundwater for the past two years, explained this meant the very wet year of 2016, when below average pumping took place, would be included in the annual average extraction calculations for this water year.
He said while this would reduce restrictions for the next water year, as the average annual extraction would be lowered by the inclusion of 2016, it also meant it would take longer to get back to normal.
"You're just transferring the problem forward and it will impact us in 2021-22," he said.
"The only way that will be solved is if you went into a run of really wet years where people could substitute surface water for groundwater or if we reduce the amount of carryover."
Reducing carryover to increase reliability
Both Mr Dal Broi and Mr Toscan agreed that groundwater carryover needed to be reduced.
"Carryover is 200pc, so you can start the water year with 300pc in your account if you're given a 100pc allocation," Mr Toscan said.
"It's far too generous, it favours the trader and undermines reliability."
Mr Dal Broi said he thought both carryover and extraction limits were too high.
"That's what causes these issues, we're in a drought but everyone just runs their bores 24 hours a day, all year round.
"It's also become more of an issue because there are now so many bores in the system.
"How much water someone could get out used to be limited on the physical pump, we have two bores and we're fairly well serviced with two pumps, we can pump our extraction limit and that's about it.
"But, now because there are more bores out there, if there were farmers that had some extra capacity they could sell that on to someone else."
The Murrumbidgee is not the only area facing a reduction in groundwater allocation, the Great Artesian Eastern Basin Recharge, which stretches across Queensland, the Northern Territory, South Australia and northern NSW, will also have restrictions.
The Upper Namoi Zone 3 is close to exceeding its compliance trigger, with a reduction in allocation dependent on final metering data.