Goyder's Line
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Goyder's Line is an imaginary line across South Australia indicating the edge of the area suitable for agriculture. North of Goyder's Line, the rainfall is not reliable enough, and the land is only suitable for grazing on a long-term sustainable basis. It traces a distinct change in vegetation between the scrub bushes known as mallee to the south and the arid salt bush to the north. This change forms a line across the state, and Goyder's line almost exactly represents the demarcation of a long-term average of 10 inches (254mm) of rain per year.
Goyder discouraged farmers from planting crops north of his line, declaring that land only suitable for light grazing. However farmers were optimistic, and it was a year of bumper rains, so many ignored Goyder and started farms. A few years later many had to abandon their farm, as Goyder had been correct and the land was indeed unsuitable for crops. Many farmhouse ruins can be seen near Goyder's line.
There have been periods of development north of the line, but invariably nature has won out, and the towns and farms have been abandoned on a return to longer-term average rainfall. It is amazing that the line has proven remarkably accurate since it was surveyed in only two months in 1865 by George Woodroffe Goyder, then the surveyor-general of South Australia. However, the effect of increasing greenhouse gases contributing to global warming has worried many meteoroligists that the line may not be true.
It is easy to see Goyder's line when flying over this area. The change in flora is very distinct when one knows what to look for.
Goyder's Line became a National Trust of Australia Heritage Icon in 2003, joining other South Australian icons such as Humphrey B. Bear, brush fencing, and Penfolds Grange wine.
Goyder's line starts on the west coast near Ceduna and goes south-east across Eyre Peninsula to strike Spencer Gulf near Arno Bay. It continues from near Moonta north to Crystal Brook and Orroroo then south-east past Peterborough and Burra to the Victorian border near Pinnaroo, crossing the Murray River south of Blanchetown. Much of the land immediately north of the line is covered by saltbush. Agriculture is possible near the Murray River further upstream only because of irrigation using water drawn from the Murray.
References
- Reader's Digest Illustrated Guide to Australian Places (page 538), ISBN 0864383991