South Australia's eastern border should have been a straight line all the way, but a surveying error creates a zigzag border where the Murray enters the state.
Image: Google Earth & Ruland Kolen
- A 19th-century surveying error created a complicated tripoint on the Murray River in eastern Australia.
- Officially, the dispute about the zigzag border between South Australia and Victoria was settled in 1914.
- COVID-19 is making life so difficult for the locals that now they want to switch sides again.
Straight, but with a little swerve
Sunset in South Australia's Riverland, close to the zigzag border with Victoria and New South Wales.
Image: Yuri Obst – CC BY-SA4.0
South Australia's eastern border looks like one of those unswervingly straight lines that zip through deserts and other thinly settled parts of the world without the slightest deviation. And indeed, it starts at the 26th parallel as it ends 833 miles further south, on the sandy shores of the Southern Ocean: straight as an arrow.
But swerve it does. Zoom in on the place where that border meets the Murray. That mighty river flows into South Australia from the east, where it forms the border between New South Wales (NSW) to the north, and Victoria to the south. Here, South Australia's eastern border hitches a ride of about three miles downstream before it resumes its southward plunge.
The result is a zigzag border – a wonderful anomaly, if you're into that kind of thing. But if you're local, that border is nothing but trouble. And with the coronavirus further complicating things, many now want the anomaly gone. Quite a few local Victorians want the border drawn as was intended by South Australia's founding document, almost two centuries ago. That would make them citizens of South Australia, the state where they do most of their business anyway.
In 1836, the Letters Patent that established what was initially known as the colony of South Australia declared that its eastern border would be the 141st meridian east of Greenwich.
At that time, South Australia had only one neighbor to the east: NSW. But not for long. In 1839, NSW south of the Murray River became the District of Port Phillip, and in 1851 that district became the separate colony of Victoria. The new colony inherited its western border from NSW. However, back in the 19th century, defining a border on a map was one thing; demarcating it on the ground, in the Australian Outback no less, was quite another.
In 1839, surveyor Charles Tyers left a giant arrow made out of limestone rock just east of the mouth of the Glenelg River, at a spot he had calculated as being the 141th meridian. Tyers' Arrow, on the Southern Ocean, was supposed to be the starting point of an inland surveying expedition.
Owen Stanley, captain of HMS Britomart, made sure that would never happen. Visiting the location some time after Tyers' expedition, he estimated that the latter's mark was 2.25 miles east of the 141st meridian. This is where the trouble started, because Stanley's correction was due to faulty equipment. And Tyers had, in fact, been right.
Half a pint of horse blood
South Australia's northern border is the 26th parallel south, which is also the starting point of its eastern border, at the 141st meridian east – but only until the Murray River.
Image: Wikimedia Commons & Ruland Kolen
By the mid-1840s, land disputes between sheep farmers in the area between the Murray and the sea necessitated a demarcation of the border between South Australia and the District of Port Phillip. In 1847, surveyor Henry Wade laid down 123 miles of border in a straight south-north line – starting from the point established by Stanley instead of Tyers.
Due to harsh conditions, difficult terrain and broken equipment, Wade had to give up surveying about 155 miles south of the Murray River. Nevertheless, both South Australia and NSW soon accepted his line as the boundary between both territories.
In 1849, Wade's co-surveyor Edward White completed demarcating the boundary north to the Murray – but in conditions even harsher than on the previous expedition. After just two weeks in the waterless Big Desert, his men had mutinied and two of this three horses had died. When the last one lay down, White drank half a pint of its blood, "which was thick, black and unhealthy-looking and had the same bad smell as his breath," he later wrote in his diary. Whether or not thanks to that drink, he managed to stagger on for two more miles – reaching the Murray and completing the survey.
By that time, it was already clear that the Wade-White line wasn't the true meridian. However, both sides having accepted the line for what it was, the new state of Victoria upon its establishment in 1851 inherited the mistake in its favor.
In 1868, it was time to demarcate the border north of the Murray. By then, better instruments were available. So, for the border between South Australia and NSW, it was agreed to revert to the 141st meridian, as per the original definition.
As a result, South Australia's eastern border follows the Wade-White line south of the Murray, and the 141st meridian to the river's north. Hence the zigzag at the tripoint with NSW and Victoria, which is called MacCabe Corner.
Case un-closed
MacCabe Corner is one of five named state border junctions in Australia. Surveyor Generals Corner is at the tripoint of Western Australia (WA), South Australia (SA) and the Northern Territory (NT).Poeppel Corner is at the tripoint of NT, SA and Queensland (QLD).Haddon Corner is where the SA-QLD border takes a 90° turn south.Cameron Corner is at meeting point of SA, QLD and New South Wales (NSW).MacCabe Corner is at the tripoint of SA, NSW and Victoria (VIC).
Image: Yarl, Papayoung & Summerdrought - CC BY-SA 3.0
For South Australia, that zigzag was a stark reminder of what it had lost: a strip of land between the Murray and the sea, 2.25 miles wide and 280 miles long – in all, more than 500 square miles.
For decades, South Australia disputed Victoria's ownership of the strip, and tried to reclaim it (or at least get compensated for it). But that was like trying to close the barn door long after the horse had bolted: by 1849, the District of Port Phillip had already sold or leased out 47 percent of the disputed land.
Due to the dispute, the contested strip of land continued to be a bit of a grey zone, legally. In a 1901 referendum, one local cast his vote as a Victorian one day, and as a South Australian the next.
The grey zone was finally erased in 1914, when the Privy Council in London pronounced in favor of Victoria. The court acknowledged that a surveying mistake had been made; but the erroneous border had been accepted by both sides, and that was that.
End of story? Well, not quite. Not if it's up to the good people of Lindsay Point, an almond-growing community just south of the tripoint, entirely within Victoria – but mainly west of the 141st meridian.
The nearest Victorian cities are more than 100 miles to the east. Most farmers and other locals are oriented towards the Riverland region in South Australia, where they go to school and do all of their business. Conversely, many properties in and around Lindsay Point are owned by South Australians. Even the power comes in from South Australia.
Irrelevant and inconvenient
Close-up of the zigzag border near MacCabe Corner, the tripoint where South Australia, New South Wales and Victoria meet, on the Murray River.
Image: Google Earth & Ruland Kolen
That level of cross-border economic integration came under pressure in recent months, when Australia's states started imposing restrictions on interstate travel, due to COVID-19. Specifically, a border lockdown preventing Victorians from entering South Australia has cut off Lindsay Point from its natural hinterland.
With that state border irrelevant in the best of times, and bloody inconvenient in the worst of times, many locals are dusting off the old territorial dispute. Increasingly, they are convinced that the Privy Council's verdict should not be final, and that it should be settled in favor of the side that lost the first time around.
If it ever does, the result will surely count as the longest, narrowest strip of territory ever to change hands.
More on the low rumblings of secessionism in Lindsay Point in this ABC News story.
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Image source: Christian Zimmerman/USGS/Big Think
Surprising Science
- A remote area visited by tourists and cruises, and home to fishing villages, is about to be visited by a devastating tsunami.
- A wall of rock exposed by a receding glacier is about crash into the waters below.
- Glaciers hold such areas together — and when they're gone, bad stuff can be left behind.
The Barry Glacier gives its name to Alaska's Barry Arm Fjord, and a new open letter forecasts trouble ahead.
Thanks to global warming, the glacier has been retreating, so far removing two-thirds of its support for a steep mile-long slope, or scarp, containing perhaps 500 million cubic meters of material. (Think the Hoover Dam times several hundred.) The slope has been moving slowly since 1957, but scientists say it's become an avalanche waiting to happen, maybe within the next year, and likely within 20. When it does come crashing down into the fjord, it could set in motion a frightening tsunami overwhelming the fjord's normally peaceful waters .
"It could happen anytime, but the risk just goes way up as this glacier recedes," says hydrologist Anna Liljedahl of Woods Hole, one of the signatories to the letter.
The Barry Arm Fjord
Camping on the fjord's Black Sand Beach
Image source: Matt Zimmerman
The Barry Arm Fjord is a stretch of water between the Harriman Fjord and the Port Wills Fjord, located at the northwest corner of the well-known Prince William Sound. It's a beautiful area, home to a few hundred people supporting the local fishing industry, and it's also a popular destination for tourists — its Black Sand Beach is one of Alaska's most scenic — and cruise ships.
Not Alaska’s first watery rodeo, but likely the biggest
Image source: whrc.org
There have been at least two similar events in the state's recent history, though not on such a massive scale. On July 9, 1958, an earthquake nearby caused 40 million cubic yards of rock to suddenly slide 2,000 feet down into Lituya Bay, producing a tsunami whose peak waves reportedly reached 1,720 feet in height. By the time the wall of water reached the mouth of the bay, it was still 75 feet high. At Taan Fjord in 2015, a landslide caused a tsunami that crested at 600 feet. Both of these events thankfully occurred in sparsely populated areas, so few fatalities occurred.
The Barry Arm event will be larger than either of these by far.
"This is an enormous slope — the mass that could fail weighs over a billion tonnes," said geologist Dave Petley, speaking to Earther. "The internal structure of that rock mass, which will determine whether it collapses, is very complex. At the moment we don't know enough about it to be able to forecast its future behavior."
Outside of Alaska, on the west coast of Greenland, a landslide-produced tsunami towered 300 feet high, obliterating a fishing village in its path.
What the letter predicts for Barry Arm Fjord
Moving slowly at first...
Image source: whrc.org
"The effects would be especially severe near where the landslide enters the water at the head of Barry Arm. Additionally, areas of shallow water, or low-lying land near the shore, would be in danger even further from the source. A minor failure may not produce significant impacts beyond the inner parts of the fiord, while a complete failure could be destructive throughout Barry Arm, Harriman Fiord, and parts of Port Wells. Our initial results show complex impacts further from the landslide than Barry Arm, with over 30 foot waves in some distant bays, including Whittier."
The discovery of the impeding landslide began with an observation by the sister of geologist Hig Higman of Ground Truth, an organization in Seldovia, Alaska. Artist Valisa Higman was vacationing in the area and sent her brother some photos of worrying fractures she noticed in the slope, taken while she was on a boat cruising the fjord.
Higman confirmed his sister's hunch via available satellite imagery and, digging deeper, found that between 2009 and 2015 the slope had moved 600 feet downhill, leaving a prominent scar.
Ohio State's Chunli Dai unearthed a connection between the movement and the receding of the Barry Glacier. Comparison of the Barry Arm slope with other similar areas, combined with computer modeling of the possible resulting tsunamis, led to the publication of the group's letter.
While the full group of signatories from 14 organizations and institutions has only been working on the situation for a month, the implications were immediately clear. The signers include experts from Ohio State University, the University of Southern California, and the Anchorage and Fairbanks campuses of the University of Alaska.
Once informed of the open letter's contents, the Alaska's Department of Natural Resources immediately released a warning that "an increasingly likely landslide could generate a wave with devastating effects on fishermen and recreationalists."
How do you prepare for something like this?
Image source: whrc.org
The obvious question is what can be done to prepare for the landslide and tsunami? For one thing, there's more to understand about the upcoming event, and the researchers lay out their plan in the letter:
"To inform and refine hazard mitigation efforts, we would like to pursue several lines of investigation: Detect changes in the slope that might forewarn of a landslide, better understand what could trigger a landslide, and refine tsunami model projections. By mapping the landslide and nearby terrain, both above and below sea level, we can more accurately determine the basic physical dimensions of the landslide. This can be paired with GPS and seismic measurements made over time to see how the slope responds to changes in the glacier and to events like rainstorms and earthquakes. Field and satellite data can support near-real time hazard monitoring, while computer models of landslide and tsunami scenarios can help identify specific places that are most at risk."
In the letter, the authors reached out to those living in and visiting the area, asking, "What specific questions are most important to you?" and "What could be done to reduce the danger to people who want to visit or work in Barry Arm?" They also invited locals to let them know about any changes, including even small rock-falls and landslides.
