Aquifer option ‘being ignored’

Monday, 7th August, 2017

By Andrew Robertson

Abundant, high-quality groundwater at Menindee could provide Broken Hill with the supply it needs at a fraction of the cost of the Murray pipeline, according to experts.

Wading in on the pipeline debate, the group of hydrologists claim the NSW Government ignored findings of an extensive scientific study carried a number of years ago that looked at groundwater as an alternative source for the city. 

The Broken Hill Managed Aquifer Recharge (BHMAR) project was the federal government’s response to Broken Hill’s water supply crisis during the millennium drought, and a desire to “improve water efficiency” at the Menindee Lakes Scheme.

The three-year study led by Geoscience Australia found a “sustainable, good quality water supply” in an area about 15km south of Weir 32 on the eastern side of the Darling.

The National Centre for Groundwater Research and Training said the NSW Department of Primary Industries Water recently confirmed the “Jimargil” site as the most suitable area for a managed aquifer recharge scheme.

But it said a report on the department’s website instead chose to focus on an investigation some 20km away, in a much deeper aquifer containing saline groundwater that would require desalination.

“There is no explanation of why the Jimargil site, now called Talyawalka, was not considered,” the centre said in a media release.

“It would seem to meet the four claimed criteria; security, service level, water quality and cost, comparably or significantly better than the proposed Murray pipeline.”

The government has previously said that the Murray pipeline was found to be the best solution for Broken Hill following an extensive evaluation of water supply options.

However, the minister has refused to release the business case for the pipeline, which presumably would include cost comparisons with other options that were considered.

The National Centre said it now appeared those comparisons were only ever done with “a very inferior” groundwater option.

“The International Association of Hydrogeologists (IAH) wrote several times to the department seeking clarification on this and has not received an explanation,” the release said. 

“No information or evidence has been provided publically that we are aware of, nor provided to IAH, for a scientifically defensible reason to rule out this Talyawalka option that could save taxpayers and Broken Hill residents hundreds of millions of dollars.”

Professor Peter Dillon, an adjunct professor at Flinders University and co-chair of the International Association of Hydrologists, said managed aquifer recharge was used widely around the world and in some parts of Australia.

He said the scheme could be used to augment and secure supplies in the event of extended drought.

“Pumping from this groundwater resource would not deplete Darling River water at low flows due to the blanket of clay lining the lower bed in this area,” Dr Dillon said.

“As well, filtration through the sandy aquifers also means the groundwater is much cleaner than water currently drawn directly from the River Darling.”

The groundwater option would require construction of wells, a 27km pipeline to Menindee, and maintenance to the existing 114km Menindee to Broken Hill pipeline.

But Dr Dillon told the BDT that the cost of the work would be “way less” than half the cost of the 270km Murray pipeline.

Regional Water Minister Niall Blair’s office repeated the minister’s position that the Murray pipeline was the best option.

“The River Murray to Broken Hill Pipeline was identified by experts from DPI Water, NSW Public Works and Infrastructure NSW as the best solution to this challenge as it provides long-term water security with a supply sourced from the River Murray,” a spokeswoman said.

“The consideration of the various water supply options involved extensive economic, social, environmental and technical analysis to ensure that only options that were feasible were taken forward.”