earth science

Goyder's Line

Goyder's Line is a earth science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Goyder's Line rather than just read about it. In short: Goyder's Line is a line that runs roughly east–west across South Australia and, in effect, joins places with an average annual rainfall of 10 inches (250 mm). North of Goyder's Line, annual rainfall is usually too low to support cropping, with the land being suitable only for grazing.

Key takeaways

Goyder's Line belongs to earth science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Goyder's Line to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Goyder's Line from memory before moving on to harder problems.

Reference excerpt

Goyder's Line is a line that runs roughly east–west across South Australia and, in effect, joins places with an average annual rainfall of 10 inches (250 mm). North of Goyder's Line, annual rainfall is usually too low to support cropping, with the land being suitable only for grazing. Related to that, the line also marks a distinct change in vegetation. To the south, it is composed mainly of mallee scrub, whilst saltbush predominates to the north of the line.

History

With barely 30 years' knowledge of this new country, farmers needed reliable information about the climate and growing conditions. In 1865 George Goyder, the then Surveyor-General of the colony, was asked to map the boundary between those areas that received good rainfall and those experiencing drought. After traversing an estimated 2,000 miles or 3,200 kilometres on horseback (not including the Eyre Peninsula) in November 1865, he submitted his report and map to the colonial government on 6 December. The map included a line of demarcation, the areas north of which being those Goyder judged "liable to drought", with the areas to the south deemed arable. He discouraged farmers from planting crops north of his line, declaring this land suitable only for light grazing. Goyder's report was based on the information already in his office, supplemented by the observations made during the 1865 journey to observe the effects of drought. He was guided in drawing the line by the changes in vegetation, especially various kinds of saltbush. Ample rains fell in most years between 1867 and 1875, prompting farmers to ignore Goyder's report and settle in the north, starting farms and planting crops. The idea that rain follows the plow, developed during the contemporaneous westward expansion of cropping in the United States, encouraged this trend. A few years later, many had to abandon their properties. The land was indeed unsuitable for crops, and Goyder was proved correct. Many farmhouse ruins can still be seen in the vicinity of Goyder's line. Goyder's Line was embodied in Schedule 1 of the Waste Lands Alienation Act 1872 which prohibited purchase of land on credit outside of designated agricultural areas. However a few good seasons led to the repeal of that act in 1874. There were other periods of development north of the line but, invariably, adverse conditions proved decisive. Entire towns and farms were abandoned when there was a return to longer-term average rainfall patterns. The line has proven highly accurate, a notable feat given the relatively limited knowledge of the local climate and overall climatology at the time it was surveyed. In December 2015, climate scientist Peter Hayman stated that the current "warming, drying trend" of South Australia's climate would definitely "put a downward shift on Goyder's Line" towards the south.

Location

Goyder's Line starts on the west coast near Ceduna and runs south-east across the 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. Agriculture is possible north of the line near the Murray River, only because of irrigation using water drawn from the river. When flying over the area, the distinct change in flora makes it possible to see the approximate path of Goyder's Line.

Cultural significance Goyder's Line became a National Trust of Australia Heritage Icon in 2003. Other states have similar conditions where parts of a state are arable but other parts are suitable only for pastoral grazing; however, no other state has a surveyed line equivalent to Goyder's line.

See also Arid Diagonal (arid and semi-arid belt in South America) Great Plains (semi-arid area of Canada and the United States) Palliser's Triangle (semi-arid area of Canada) Semi-arid climate Australian wheatbelt

References

Illustrations

Goyder's Line: Satellite image of vegetation and desert in South Australia. George Goyder provided advice as to the geographic limits of crop growing in South Australia. — Satellite image of vegetation and desert in South Australia. George Goyder provided advice as to the geographic limits of crop growing in South Australia.

Goyder's Line: Detail of memorial cairn near Redhill, showing a map of Goyder's Line within the southern portion of South Australia — Detail of memorial cairn near Redhill, showing a map of Goyder's Line within the southern portion of South Australia

Worked examples

Example 1 — a first encounter with Goyder's Line

Start with the simplest possible case. Write down what Goyder's Line claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Goyder's Line before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Goyder's Line ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Goyder's Line

In research: Goyder's Line appears in earth science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Goyder's Line in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Goyder's Line is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1860s in South Australia, Agriculture in South Australia, Geography of South Australia, so understanding it makes those chapters shorter.
In everyday life: Look for Goyder's Line outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Goyder's Line in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Goyder's Line means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Goyder's Line out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Goyder's Line in simple terms?

Why does Goyder's Line matter?

Because it connects several earth science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Goyder's Line?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Goyder's Line.