Sarah Hanson-Young (SA, Australian Greens) Share this | Link to this | Hansard source

I move:

That the Senate take note of the answer given by the Special Minister of State (Senator Faulkner) to a question without notice asked by Senator Hanson-Young today relating to the Murray-Darling Basin system.

The Lower Lakes and Coorong are in desperate need of new sources of water as soon as possible, and freshwater flows must be restored by summer if the lower reaches of the Murray are to have any chance of survival. Despite the common myth that salt water was freely flowing throughout the lakes before the barrages were implemented 70-odd years ago, Lakes Alexandrina and Albert were predominantly fresh water, and while the mighty Murray mouth was kept open by the river flows released into the ocean, saltwater intrusion into the lakes environment was not considered common until at least after 1901, when the water resource development upstream—that is, irrigation—throughout the Murray-Darling Basin was removing significant volumes of water.

Calls to open up the barrages and allow salt water to flow into the freshwater units throughout the Lower Lakes has been widely criticised due to the documented widespread ecological, social and economic impacts that such a move would cause. In particular, concern has been raised around the impact saltwater flooding would have on irrigators, graziers and the tourism sector in the lower reaches of the Murray while they are reliant on the services of the lakes as a freshwater ecosystem. Most importantly, we have heard that, while the minister believes that salt water is the inevitable solution to save the lower stretches of the Murray, without significant inflows the environment of the Lower Lakes would progressively increase in salinity, causing an increase in algae, mosquitos and bacteria and essentially making it increasingly difficult to repair the damage that has already been caused by overallocations of water further upstream.

The best option for preventing this acidification is fresh water. Sea water, which contains sulphate iron—that is, the precursor to sulphuric acid—may simply exacerbate the problem, so it is concerning that the minister for water does not seem to understand the devastating ecological impact that this proposal is set to cause. I note from the minister’s answer earlier today that no risk assessment has been conducted, yet it continues to be the option that is pushed by the minister and her department. If salt water is released, we will likely witness species of fish becoming unable to adapt to the new salinity levels of the lakes and disappearing before our eyes. Other aquatic fauna will also be severely affected by this influx of sea water, which will ultimately have secondary impacts on the food chain.

We have also heard that the flooding of the lakes with salt water may contaminate the groundwater of the Fleurieu Peninsula region through the recharge mechanisms under the lakes. The contamination of groundwater is a significant issue that should not just be swept aside. It will have significant and long-term effects on the freshwater supplies stretching far beyond the edge of Lake Alexandrina and Lake Albert. If the minister needs any other reason not to go down the saltwater flooding path, it is important to understand that if we flood the lakes with salt water we will still require 350 gigalitres of fresh water to dilute the saltwater intake. This is clearly not a silver bullet. Where would we find this 350 gigalitres of fresh water? Where does the minister propose it comes from? Keeping in mind that it is 350 gigalitres of fresh water, if we got that into the lakes system now or before Christmas we could hold the current crisis at bay.

I urge the minister and the Rudd government to commit to conducting a comprehensive risk assessment of the devastating impact saltwater flooding will have on the groundwater of the Fleurieu Peninsula region and ensure that no commitment is made to such an environmentally drastic option until an assessment is conducted. It is simply the most responsible thing to do. Once you let saltwater flows into the lakes, they will be damaged in such a way that they will never be able to fully recover. We are seeing here a policy that is essentially giving the green light to destroying Storm Boy country forever. I once again urge the minister to conduct a risk assessment urgently before continuing to push the barrow of salt water going into the lakes.

Question agreed to.