Red Mud Dam
Near Gladstone in Queensland, Australia is a gigantic, bright-orange lake known as Red Mud Dam. Although the explanations I found were a little confusing, it seems that the colouring is due to residue formed through the process of extracting aluminium from bauxite. I think.
You can see that the colour only seems to be affecting about 2 thirds of the lake, as I believe the mud is processed to remove the residue.
However, I’m sure someone out there will correct me, even if I’m right 
Thanks to Stuart Moffatt and Stephen Hope.
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This the Bridgewater Canal in Salford.
Placemark: Google Maps / Google Earth
It was the the first canal to be built in Britain and was built to transport coal into Manchester. The iron ore present in the mines stains the water orange. Not quite on the same scale as your Australian lake but watery and orange non the less.
Better view of the orange water and more info here
http://www.salford.gov.uk/living/yourcom/salfordlife/bridgewatercanal.htm
Um… Would it be safe to swim in something like that? :p
I used to swim in the Susquehanna river in wester Pennsylvania (USA) and it was colored that bright orange color from the coal plants up river. No one ever stopped me and I have yet to grow a third leg some 15 years later, so I think all is good.
I remember seeing this orange lake as a kid. It is in the famous mine town of Bisbee, Arizona. It is just a few miles from the even more famous Tombstone. It is from when the copper pits collect rainwater, causing tailings to turn the water a deep orange. While this is copper, I bet the same thing is happening in Australia, presumably with iron-oxide.
Placemark: Google Maps / Google Earth
The red/orange color you see is mostly iron oxides left from the bayer process, which is used to refine bauxite to alumina. The red part is the dried out areas of the “slimes dam” and the dark part is the liquid part. I contains huge consentrations of caustic soda (part of the bayer process). You could get a nice skin-peel if you try to swim in that water. cheers
The red color is the the mud extracted from the bauxite to make alumina at the QAL plant through the bayer process. This photo is of their tailings dam which is approx 650 acres in size.
Railyards in Northern WI, Ashland and Superior,used for iron ore, show up as orange on Google earth. Is that because of the type of photo process? It doesn’t show up in higher resolution photos.