Water

Reports throws further doubt over demand for more water to maintain lower lakes

By Geoff Adams

A new scientific report has thrown further doubt over the demand for more Murray-Darling Basin water to be used to maintain the Murray River’s Lower Lakes as freshwater bodies.

A central plank of South Australia’s demand for water under the Murray-Darling Basin Plan is the need to maintain freshwater levels in the huge Lower Lakes near the Murray Mouth.

Goulburn Valley irrigators have complained they are losing valuable irrigation water to maintain a freshwater system in the Lower Lakes, when the lakes have historically been subject to saline seawater.

Naring irrigator Barry Croke said the Lower Lakes required as much water as northern Victoria required for irrigation (about 1000Gl).

‘‘We can either have salty lakes made fresh or an industry in northern Victoria,’’ Mr Croke said.

The new report is by paleo-ecologist Peter Gell, who also makes a claim that the South Australian Government is using misleading research to endorse its push for freshwater in the lakes.

‘‘The allocation of large volumes of freshwater to achieve this condition presents significant difficulties owing to the highly contested nature of water use across the basin,’’ Prof Gell said in his summary.

Prof Gell, from Federation University based in Ballarat, specialises in studies of coastal waterways and examining their historical role.

‘‘The now generally accepted, but erroneous, position that Lake Alexandrina has been fresh for 7000 years provides an important foundation for the need for additional freshwater flows down the Murray River, as agreed in the Murray-Darling Basin Plan,’’ Prof Gell found in his latest report.

The recent South Australian Royal Commission into the Murray-Darling Basin Plan was given evidence about the status of the Lower Lakes, but the final report did not refer to Prof Gell’s work, despite several people drawing attention to the science.

Former NSW State Member for Murray Austin Evans, who is also a former engineer, called attention to the peer-reviewed paper by Prof Gell.

Mr Evans said the paper clearly showed the science-based position was that the Lower Lakes were always a mostly estuarine system that only occasionally became predominantly fresh during large flood events.

‘‘This only changed to predominantly freshwater once the barrages were put in,’’ he said.

‘‘As Peter Gell states in his paper, this has been obfuscated by various scientists and the South Australian Department of Environment (amongst others).

‘‘At best this has been as the result of sloppy academic work possibly influenced by confirmation bias; at worst it is a deliberate collusion driven by ideology to achieve a political outcome.’’

The new NSW State Member for Murray Helen Dalton called for a nationwide conversation about the Coorong, saying this environment had been in decline since the 1880s and environmental damage would now appear to be irreversible.

‘‘The continued draining of the nation’s financial resources needs to be questioned when this system continues to fail regardless of investment,’’ Mrs Dalton said.