For some time, there has been a contested view that the Lower Lakes at the mouth of the Murray River were in fact saline as opposed to being freshwater lakes.
According to a study undertaken by an independent panel appointed by the Murray Darling Basin Authority (MDBA), the committee has since 2019, consulted with almost 100 scientists and technical experts and reviewed hundreds of documents and papers to reach their final position.
In May, they delivered their findings to the MDBA. The panel found that while some knowledge gaps were evident, the science of the Coorong, Lower Lakes and Murray Mouth was well understood. The panel outlined that the available research findings are consistent and that the Lower Lakes are being managed appropriately.
The key finding was that the Lower Lakes were largely fresh prior to European settlement.
Local Member for Shepparton District, Suzanna Sheed said, “I like many others have been very disappointed with the increasing levels of toxicity and division between the basin states and within communities. Mr Keelty has recently reiterated this concern. We need to start a new conversation focusing on what is actually achievable under a basin plan that has been endlessly reviewed and shown to have many flaws.
“The ‘Independent Review of Lower Lakes Science Informing Management’ report is a good place to start a new conversation. While it maintains that the lake’s recent history as a largely freshwater estuarine system is now settled, it also clarified this will not be its future with climate change and rising sea levels.
“In light of the report together with the recent Wentworth Group report, which made similar findings regarding the impacts of climate change and rising sea levels on the Lower Lakes, it would be futile to continue to demand irrigators in my electorate sacrifice their water share to sustain the Lower Lakes in their present condition.
“I urge the Basin Ministerial Council to ensure that this most important issue is discussed at its forthcoming meeting this month and a new and realistic direction adopted.”
According to the information available to the panel, the pre-development long-term average annual inflow from the Murray River is more than 13,000 gigalitres. This volume would fill the lakes on average more than eight times a year. Over the years however, upstream development has reduced the flow into the lakes to less than half, res ulting in more frequent incursions of salt water into them.
The barrages were built in 1940 in response to these changes, isolating the Coorong and the sea from the Lower Lakes. According to the committee, removing the barrages would have significant ecological and socio-economic impact and it would not result in any water saving if targets informed by science and modelling and envisaged under the basin plan are to be met.
Further aspects to be considered in addressing the Lower Lakes is climate change and an anticipated rise in sea levels requiring even more Murray river flow into them, in conflict with less water in the Murray being available for the same reasons.
