Acknowledge Lower Lakes were once estuarine, says Speak Up

It especially refers to a 2009 report, commissioned by the South Australian Department of Environment, Water and Natural Resources, which claimed the Lower Lakes had traditionally been a freshwater system.

This report was the basis on which significant parts of the Murray-Darling Basin Plan have been developed.

However, a recent peer-reviewed publication in the CSRIO journal Pacific Conservation Biology said the Lower Lakes were historically an estuarine system with marine incursion.

"We believe the 2009 report … has contributed to huge social, economic and environmental damage to parts of our nation," the letter, organised by the Speak Up campaign, said.

The letter said the Lower Lakes had also suffered environmental damage, because in their freshwater state they were hosting millions of the pest species European carp, and harming the critically endangered Murray hardhead, which thrives in brackish water.

“We believe a report which did not make it clear, despite evidence to the contrary, that the Lower Lakes were once part of an estuarine system has created so much unnecessary hurt, pain and damage, and we believe a clear statement acknowledging the traditional state of the Lower Lakes should be released,” the letter said.

It also asks the university and government:

• Were you aware of the misleading nature of the report which claimed the Lower Lakes did not have substantial marine incursions?

• What processes are in place to ensure reports do not form the basis of political advocacy, but are based on facts and information, not ideology and politics?

• What steps are being taken to ensure the facts and correct information are made public to ensure reports which could be considered misleading are rectified?

Speak Up chair Shelley Scoullar said the importance of acknowledging the Lower Lakes were once estuarine could not be overstated.

“The basin plan was built on this premise, and as a consequence huge volumes of freshwater are being poured down the Murray River at massive social and economic cost," Mrs Scoullar said.

“Yet we now have a CSIRO peer-reviewed report which tells us this is not the case; a fact that has been obvious to many people for a long time."

The letter was signed by 17 organisations across three states, including South Australia. It includes Edward River, Berrigan, Murrumbidgee and Murray River councils, Deniliquin and Griffith business chambers, farming and community groups.