Saving the lower Murray

· DartmouthDam,

· Hume Weir,

· The Locks along the River Murray,

· The Barrages.

Prior to the above the River Murray flowed unobstructed emptying into the ocean and history tells that on average some 2-Gigalitres per day or 730-Gigalitres flushed the impurities out of the River's mouth each year.

The infrastructure was constructed to ensure water for many reasons including human consumption, stock requirements, the growing of food, a pool level sufficient to ensure paddle steamers were able to travel from Goolwa along the length of the River Murray white man needed to ensure a reliable water supply.

In times of low inflows into the River Murray ie, 1914 willows at Wellington found to be dying as a result of salt water being there and then in 1915 saltwater in the River at Mannum and reports of saltwater also upstream of Mannum. This was about the time a friend of mine told me he caught a Whiting at Younghusband.

In 1930's: - Building of barrages commenced and by the 1940's the Locks along the River Murray were completed ensuring SA's potable water supply. (The first planning was for 26 Locks along the River Murray)

We must remember the Barrages were part of a trade-off for the construction of Lake Mulwala.

Now let's look at the ramifications of either allowing seawater into Lake Alexandrina or worse removing the Barrages!

If either allowing seawater into Lake Alexandrina or worse removing the Barrages were permitted during times of low inflows into the Murray Darling Basin and no worthwhile flow (or worse no flow) over Lock 1 ie, enough to hold back the seawater the pool level would immediately drop to sea level and the sea could permeate to downstream of Lock 1. This worst case scenario the River Murray flora and fauna in the Lower River Murray would perish no potable water supply for Adelaide and the greater percentage of South Australians and our reservoirs would empty and the only potable water supply would be from SA's desalination plant at Pt. Stanvac.

The main problem is mis information and total lack of understanding and I will quote one example from someone in NSW, "In the MDBA the Proposed Basin Plan Lakes Alexandrina and Albert and the Murray Mouth are basically ignored even though they annually need the Hume Dam plus to keep them fresh" what a load of rubbish the Hume Weir holds 3005-Gigalitres and the evaporation from Lakes Alexandrina and Lake Albert is less than 900-Gigalitres and please when picking on SA for our evaporation rates please consider Menindee Lakes which are also not natural.

If any move were made to allow ANY seawater into Lake Alexandrina were even contemplated another regulator would be required near Wellington and of course prior to that a complete Environmental Impact Statement would be required not only to protect SA's potable water supply but ensure correct of the Murray Darling Basin.

Finally it must be understood that the natural environment CANNOT be restored so we must work to ensure the Lower River Murray is protected for the betterment of the entire Murray Darling Basin.