Lake Alexandrina (South Australia) - History

History

In the Australian Aboriginal Dreamtime the lake was inhabited by a monster known as the Muldjewangk.

Edward Wilson, visiting the lake in the 1850s described it as follows:"Lake Alexandrina is the finest sheet of fresh water I ever saw. Indeed so formidable did it look, with a stiff wind blowing up quite a sufficient swell to make one seasick, that I could scarcely believe it to be fresh. Such is the fact however. It is forty or fifty miles long by twelve or fifteen wide and the shores around it receded into the dim distance until they become invisible, in the way which we are accustomed only with ideas of salt water. Supplied almost entirely by the Murray, the whole lake retains the muddy tinge of which I have spoken, and this sadly detracts from the otherwise beautiful appearances of this magnificent sheet of water."

In 2008, water levels in Lake Alexandrina and Lake Albert became so low that large quantities of acid sulphate soils threatened to form. The soils on the lake beds are naturally rich in iron sulfides. When exposed to the air, such as may occur in a time of severe drought, the sulfides oxidize, producing sulfuric acid. The barrages now prevent seawater inflows that have prevented this phenomenon in every drought since the last ice age. A weir has been proposed near Pomanda Island to protect upriver water supplies should it become necessary to open the barrages.