A proposal that could radically reduce the storage capacity of Bundaberg's Paradise Dam has been criticised by affected cane growers who are disappointed at being left out of the loop.
SunWater officials recently met Bundaberg and North Burnett councils to discuss the dam's future, outlining options to either lower its walls or strengthen them at the current height.
The options are being considered to address historical issues with dam design and the high cost of meeting and maintaining revised safety guidelines.
Lowering the dam's wall is the cheaper option and could save between $50 million and $150 million when compared to keeping the dam at its current height, according to details of a preliminary business case shown to councillors.
It is understood strengthening the dam at its current height could cost around $600 million.
SunWater said it was not in a position to share accurate cost forecasts, although acknowledged the full upgrade option would be "significantly" more expensive.
However, critics of lowering the dam questioned whether it would cause greater economic damage by stunting the growth of emerging Bundaberg industries such as avocado and macadamia growing.
Bundaberg Canegrowers chairman Allan Dingle said he struggled to fathom how lowering the dam could even be on the table for a region so dependent on irrigation.
"There's not a lot of information around about [the proposal], but as far as I'm concerned there's only one option," he said.
"And that's to fix the dam at full height."
The presentation shown to councillors noted that only 11 per cent of the dam's total water capacity had been sold since 2005.
Mr Dingle said this completely ignored the concept of water security in a region that has a heavy economic reliance on irrigation-intensive industries.
"It's just not good for the irrigation community," he said.
"The only stakeholders worth speaking to are the irrigators. It's not worth talking about the other options."
SunWater recently dropped the price of wholesale water sold from Paradise Dam, lowering it from $950 per mega litre to $550 per mega litre.
At this lowered price SunWater had received interest from buyers to the tune of an extra 10,000ML of water sales.
Mr Dingle pointed to the uptake of this offer as evidence of a strong demand for water in the region.
The 52-metre-high Paradise Dam was built in 2005 and has a total capacity of 300,000ML.
It was damaged during floods in both 2011 and 2013.
SunWater said it needed to be improved to withstand at least a one in 15,000 year flood event, based on guidelines set by the Australian National Committee on Large Dams.
The preliminary business case put forward by SunWater considered either lowering the dam by 10 metres or 17.6 metres, or meeting this 15,000 year flood standard at its current height.
"No decision has been made regarding a preferred option," a SunWater spokesman said.
Over the next 10 years SunWater will complete improvement projects at 18 Queensland dams.
Paradise Dam has been identified as the highest priority of these projects.
LNP member for Burnett Stephen Bennett questioned how Bundaberg could be expected to grow and diversify its agricultural industries with a lower water allocation.
Lowering the dam sent all the wrong signals to prospective investors looking for water security in the region, he said.
Mr Bennett also questioned whether lowering the dam would ultimately increase competition for available water and accordingly drive up its costs.
Building Queensland is working on the Paradise Dam business case.
The business case is scheduled to be finalised by late 2019 and will be released early in 2020.