SA researchers changed Murray Darling Basin Plan science

Science justifying millions of megalitres being flushed down the Murray River to keep Lake Alexandrina fresh is based on research “altered” by Adelaide University researchers.

Fill ’er up: South Australia’s Lake Alexandrina.

EXCLUSIVE: THE science behind the Murray Darling Basin Plan is based on the work of three South Australian researchers who altered their past findings to back the claim the state’s Lake Alexandrina has been fresh for the past 7000 years.

In a crucial 22-page 2009 report to the South Australian Government, the Adelaide researchers stated: “There is no evidence in the 7000-year record of substantial marine incursions into Lake Alexandrina”.

The 2009 report, which was not peer-reviewed, formed the foundation of the South Australian Government’s argument the lake must be kept fresh, which was eventually enshrined as a key ­objective of the 2012 Murray Darling Basin Plan — to always keep salinity in the lake at less than 1500EC (seawater is about 50,000EC).

More than 1.74 million megalitres has been flushed down the Murray River over the past 12 months to help keep the massive 64,900ha Lake Alexandrina brimming with fresh water, frustrating many upstream irrigators.

Yet the basis for keeping the lake fresh is based on ­University of Adelaide researchers Jennie Fluin, her husband John Tibby and Deborah Haynes’ 2009 report, which altered their original 2007 research findings, diminishing the impact of seawater on the lake.

In their original 2007 peer-­reviewed research in the journal Hydrobiologia, the group, along with two other scientists, examined the silica skeletons of differing algal species preserved in lake sediments, called diatoms, which indicate salinity levels over the past 7000 years.

The 2007 research concluded:

“The presence of (diatom species) Thalassiosira lacustris, Cyclotella striata and Paralia sulcata indicate marine influence at this time.

“The change in diatom community (after 5000 years BP) is likely to represent a decrease in lake level and increased penetration of seawater, possibly associated with the variable, dry climate.”

But when quoting this same research in their 2009 report to the SA Government the three scientists state:

“The presence of Thalassiosira lacustris, Cyclotella striata and Paralia sulcate indicate minor marine influence at this time.

“The change in diatom community is likely to represent a decrease in lake level and increased penetration of more brackish water, possibly associated with the variable, dry climate.”

Against the tide: University of Adelaide researchers altered their original 2007 peer-reviewed research to deliver a 2009 report to government stating: “There is no evidence in the 7000-year record of substantial marine incursions into Lake Alexandrina”.

One of the five authors of the original 2007 paper, Federation University Professor Peter Gell, has condemned the changes and published a critique that has been peer-reviewed and just been published in CSIRO’s Journal of Pacific Conservation Biology.

“The terms ‘minor’ and ‘brackish’ serve to diminish the role of the ocean as a source of lake water salinity,” Prof Gell said.

He said Lake Alexandrina “was always an estuary and could not be defined as predominantly fresh until construction of the barrages”, which were completed in 1940 to stop seawater intruding into the lake.

But University of Adelaide Associate Professor John Tibby said: “We stand by our 2009 report and will be challenging the errors in Peter Gell’s 2019 article in the peer-reviewed literature.

“Academic integrity is our top priority. The (2009) report we provided to the State Government was entirely consistent with both the conclusions of the original work and the data.”

Prof Gell said there were no errors in his critique, which had been reviewed by an independent panel of four eminent scientists, selected by the CSIRO, prior to publication two weeks ago.

In his paper, Prof Gell said the change was crucial to the MDB plan, with “the new interpretation and its widespread adoption ... have appeared to strongly influence the socio-political decision-making process that has laid down an outcome of great ecological, social and economic consequence for water management”.

Full story: The Weekly Times, February 6, 2019, revealed Lake Alexandrina was brimming with water while fish in the Darling River were dying.

Further independent evidence has emerged to back Prof Gell, with the publication in Nature Scientific Reports of University of Sydney and Newcastle research that shows Lake Alexandrina has been estuarine for the past 7000 years (prior to the barrages).

The team, led by University of Sydney School of Geo­sciences researcher Anna Helfensdorfer, identified a two-metre surge in sea levels about 5500 years ago that pushed the ocean’s tidal influence more than 200km up the Murray River to Teal Flat.

“We demonstrate the estuarine limit can extend significantly further inland than expected,” the researchers reported.

“The importance of sea level in controlling the character of the Murray estuary ... suggests the impacts of future sea-level rise due to climate change on coastal plain estuaries may be underappreciated.”

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Rice Growers Association president Jeremy Morton said it defied logic that the Lower Lakes were different to every other river system with lakes that terminated at the sea.

“Why are they running some bullshit narrative that the lakes have always been fresh,” Mr Morton said. “We’re fighting against something natural.”

Minister for Water Resources David Littleproud said the Murray Darling system had been substantially altered and was nothing like what it was 7000 years ago when tides came inland 200km.

“The Basin Plan does not attempt to restore pre-development conditions,” he said.

MORE: LAKE BRIMS WITH WATER AS FISH DIE IN DARLING

EDITORIAL: BASIN PLAN MUST BE REVIEWED

ANALYSIS, PETER HUNT: SALT IN IRRIGATORS’ WOUNDS

“All science is contested and I loathe to enter scientific debate, however changes of language do concern me. I’ll be requesting more information on this.

“The political reality remains the Commonwealth, Basin states and territories agreed on the management of the Basin for the first time ever in December 2018, delivering a plan which is far from perfect but which is also the best outcome we’re going to get, because it gives two million Australians living in the Basin certainty around water for the first time in almost a decade.”