A dispute over cuts to water allocations in Western Australia's Ord Irrigation Scheme could still be months away from a resolution as parties argue whether evidence given in court by local farmers should be given preference over government bureaucrats based more than 3,000km away.

Key points: Ord irrigators have spent four years fighting a WA department plan that cut water allocation by 30 per cent

Ord irrigators have spent four years fighting a WA department plan that cut water allocation by 30 per cent The Department of Water and Environmental Regulation made the cuts because irrigators had not used their full allocation

The Department of Water and Environmental Regulation made the cuts because irrigators had not used their full allocation Irrigators say the water will be needed when various industries expand, including cotton and fodder, and decisions should not be based on a "use it or lose it" scenario

The Ord Irrigation Cooperative (OIC) has spent the past four years fighting a decision by the Department of Water and Environmental Regulation (DWER) that would see its annual 335-gigalitre water licence cut by 30 per cent.

The cuts to allocations were made by the department when it renewed the OIC's licence in 2015, stating irrigators had not been using enough of their water entitlement to justify the full allocation.

The OIC took the case to the Court of Appeal last year, where it was ordered back before the State Administrative Tribunal (SAT) that travelled to Kununurra in November to hear the case.

The SAT reconvened proceedings at the Kununurra Courthouse this week for the second round of hearings, where the court heard from four water experts before closing statements concluded on Friday afternoon.

Judge David Parry on a tour of the Ord Irrigation Scheme. ( ABC Rural: Courtney Fowler )

The main players: OIC versus DWER

The OIC, the applicant in the case, was established in Kununurra almost 25 years ago, when the WA Government returned some of the water assets, owned by the Water Corporation, to irrigators.

It is responsible for water delivery to more than 100 properties in the first stage of the Ord River Irrigation Area (ORIA).

But the water that flows through the irrigation scheme is controlled by DWER, the respondent in this case, which is responsible for issuing and renewing water licences.

The two parties and the water experts called before the court — Dr John Ruprecht, Gregory Munck, Simone McCallum, and Shaan Pawley — were unable to agree on how much water would be needed over the next 10 years of the licence.

The Ord Irrigation scheme is the result of a bold plan to develop a food bowl in Northern Australia. ( ABC Rural: Courtney Fowler )

Allocations historically not reached

DWER's counsel, Catherine Ide, argued the reduction to the original 335Gl licence was justified because the OIC had been unable historically "to demonstrate the ability to use their full licence entitlement".

"In 2018, 248.4Gl was diverted — that's 86 Gl never used by the applicant in their historical licence."

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She explained that, as part of the SAT process, experts from DWER and the Department of Agriculture had worked together with two independent experts to calculate current and future crop requirements.

She pointed to the testimony of water expert Ms Pawley, who told the court the 257Gl allocation was more than adequate for Stage 1 farmers' future crop needs.

Ms Pawley calculated future water needs in the ORIA based on historical data from 2018 and grouped her findings into "low-medium-high water use" categories.

Ms Ide told the court these crop groups' water use had remained relatively stable between 2009 and 2019 and it was "reasonable to assume stability going forward in the absence of reliable information".

Mathew Dear is the general manager of the Ord Irrigation Cooperative, the applicant in this case. ( ABC Rural: Courtney Fowler )

OIC crop forecasts 'aspirational'

She said the respondent had reservations about the accuracy of 10-year forecasts provided by OIC's general manager Mat Dear, which assumed the expansion of the cotton industry and an uptake of high-water-use crops like wet and dry fodder.

In her closing statement, Ms Ide said only one farmer in the Ord, Rob Boshammer, was currently growing wet-season fodder and planned to build a feedlot in the area were aspirational given approvals had not yet been obtained and the project was contingent on outside investment.

She also told the court there was no certainty the cotton industry would expand to 3,000 hectares in Ord Stage 1 within the course of the licence, which was the scale required to build a processing gin and make the industry profitable.

A cotton field at the Ord River in the Kimberley region of Western Australia. ( ABC News: Kristy O'Brien )

Ms Ide argued to grant the full 335Gl water allocation based on either of these "speculative" crop forecasts would be wrong, and there was flexibility to apply for additional water in future if needed.

"The story of needing water for future projects is a story as old as time [and] often a source of tension between applicants and the regulator," she said.

Finally, she told the court she held doubts about the impartiality of OIC's water experts and witnesses, arguing the SAT should trust the experience of consultants who had no connection to business in the area.

A farming area in transition

OIC's lawyer, Faye Ashworth, argued that evidence given by farmers who lived in the valley and water experts familiar with the region should be given preference over predictions made by DWER staff.

She said DWER's method of predicting future water use did not reflect what farmers had planned in the future.

"The Ord is a farming area in transition: from sugar to chia, to maize, to hay, to cotton," she said.

"One would not expect a static picture in an area that's been in transition."

Around 30,000 tonnes of Ord corn was exported from Wyndham Port across three shipments between September and November 2019. ( ABC Rural: Courtney Fowler )

ORIA crops earmarked for expansion

Ms Ashworth said the historical data was already outdated and pointed to the rapid growth of cotton and fodder in the region.

It was noted that 600 hectares of fodder was planted in 2019, with 1,000 hectares expected to be planted this year.

In contrast, DWER's data looked to the 287 hectares planted in 2018.

Kununurra farmer Rob Boshammer inspects some of the rhodes grass hay he has baled in the Ord. ( ABC Rural: Tom Edwards )

Mr Dear predicted that, by 2029, 1,250 hectares of wet and dry fodder would be grown.

Ms Ashworth also pointed to farmers' switch from chia to maize in 2015, which had become a substantial crop for the region — a trend which was forecast to grow to 2,500 hectares by 2029.

She said the amount of productive land in the Ord was earmarked to increase over this 10-year water licence, with double cropping likely to be "one of the most significant changes to farming practices in the ORIA".

She said logic dictated a significant decrease in fallow land would increase water requirements.

Water security key to investment

Water security has never been a worry in the Ord — made possible by the Lake Argyle storage dam created in 1972 to support irrigation expansion in the scheme.

With the dam holding nearly 20 times the volume of Sydney Harbour, it has the largest storage of fresh water on mainland Australia.

In her closing statement, Ms Ashworth said water security was one of the main advantages of farming in the area and helped offset the ongoing challenges such as isolation and extensive freight costs.

Lake Argyle has the largest storage of fresh water on mainland Australia. ( ABC Rural: Courtney Fowler )

She contested the "use it or lose it" approach, arguing that cutting water allocations was a short-sighted decision because farmers would need access the full 335Gl if the Ord continued to expand.

The OIC also said more than $4 million in infrastructure upgrades had been carried out by the OIC to improve the distribution efficiency of water in the scheme.

There was debate between the water experts as to the total amount of water saved, but the most conservative estimate by DWER was between 57 and 67Gl a year.

Ms Ashworth claimed DWER was now attempting to recoup those savings by reducing the licence — a move that went against the water policy.

The OIC says it has invested $4 million towards automating the gates that control the flow of the water through the M1 channel, the main diversion point to farmland in Ord Stage 1. ( ABC Rural: Courtney Fowler )

Where to now?

A decision will be handed down in the coming months by Judge David Parry and SAT members Charmian Barton and Peter Curry, who acknowledged the level of community interest in the case.

About 30 irrigators attended the opening statements in November and some farmers attended the duration of the hearing.

Mr Dear said it was pleasing the SAT visited Kununurra in order to understand the complex issues in the case.

Judge Parry said both parties had until March 27 to make final submissions.

If the tribunal's decision goes in favour of the OIC, their annual water licence will be renewed at 335GL per year.