Did the Corinth Canal turn the Peloponnese into an island? Is there a clear yes-or-no answer to this, or is the definition of “island” a sliding scale of truth values?
Wikipedia says “Indeed, the Peloponnese is rarely, if ever, referred to as an island.”
There’s no hard definition of an island, but typically, artificially dug stretches of water are considered not to count as water for the purposes of that definition. A similar example is that Afro-Eurasia is still, even after the completion of the Suez Canal, considered to be a contiguous landmass (by far the largest in the world). Much the same way artificially constructed dry connections are similarly disregarded - that’s why people still consider Britain to be an island even after the construction of the channel tunnel.
Speaking of hard definitions, the closest thing you’ll find is the definition in UNCLOS, the United Nations Convention on the Law of the Sea - an international treaty that codifies the legal regime of the seas. It includes the following provision:
Article 121
Regime of islands
- An island is a naturally formed area of land, surrounded by water, which is above water at high tide.
(…)
This is also the reason why China’s attempts to expand its territorial waters and exclusive economic zones by means of building artificial islands are not internationally recognised.
I doubt it. There’d be a helluva lot more island if it did.
Cape Cod would be an island, cut off by the Cape Cod Canal
The piece of Canada next to Niagara Falls would be an island, cut off by the Welland Canal
The piece of Wisconsin with Egg Harbor and Sturgeon Bay would be an island, cut off by the Sturgeon Bay Ship Canal
The Hamptons on Long Island would be on an even smaller island, cut off by the Shinnecock Canal
An un-named blob of land near my home town of South River NJ would be an un-named island, cut off by the Washington Canal
… and so on, and so on, and so on
South America is an island? Say it ain’t so!
Saudi Arabia would say yes as it planned to cut off its neighbor Qatar from the mainland as a political statement by building a canal.
Although northwest Scotland is part of the island of Britain, and includes many smaller islands, the mainland region isn’t usually referred to as an island because of the Caledonian Canal.
Even Long Island isn’t considered an island, but a peninsula, even though it’s separated from the mainland by water.
Maybe OP is thinking of a peninsula. Does a canal cutting across a peninsula make an island?
If someone builds a canal connecting the San Francisco Bay at San Mateo with the Pacific Ocean at Half Moon Bay (roughly, the route of State Route 92 on this Google Map), would San Francisco become an island?
No. Most of the examples given in the thread above are actually of peninsulas that have canals across them. The canals are usually at a narrow section, that is, an isthmus, because that’s the easiest place to dig them.
Whatever the legalities, or the principles of geographical taxonomy, there’s also a perceptual effect. I live on the Isle of Dogs (the bit of east London in a 'tear drop" curve). When there were dock entrances to the Thames on both sides, it could become an island while the entrances were open to ships; and over the years it came to feel like a separate community, and under-served by the powers that be - to the extent that about 50 years ago, some local activists did a “Passport to Pimlico” and ‘declared independence’.
It’s common shorthand around here to refer to it as “the island”.
This SCOTUS ruling applies in matters of maritime law, but not universally. From Wiki:
When the Chain of Rocks Canal was constructed in 1953, it sliced off an 8+ mile section of Illinois just north of St. Louis. That slice is divided by a slough which is only full during high water. Despite not technically being an island at all, this slice of land is officially two different islands, Choteau and Gabaret.
We’ve got a few cases like that down on the south coast:
Hayling Island is a legit island, probably once a connected headland, now joined only by a road bridge.
Portsea Island (Portsmouth) is an island separated only by a fairly narrow canal
Whale Island (connected to Portsea Island only by a road bridge
The Isle of Portland is perhaps the most odd - it’s connected to the mainland by a narrow strip of natural dry land (Chesil Beach)
What people call an island isn’t necessarily a very tight technical definition, I think.
If a ship canal doesn’t make an island, what about the curious case of Manhattan?
The Spuyten Deyvil Creek connected the Hudson and Harlem Rivers. But it had an odd bend in it that hurt shipping, so in the late 19th century the Harlem River Ship Canal replaced it with a straighter waterway. That had the effect of isolating Marble Hill, which is now physically part of The Bronx but politically still in Manhattan.
So is the northern end of Manhattan a natural creek or an artificial canal?
Heck, you can’t even go from Mexico to Canada without crossing some body of water or another. There’s at least one case of a lake right on the Great Divide, that drains (eventually) into both the Atlantic and the Pacific (though it’s only a trickle at the start).
North America is still one continent.
Yeah, but the East River isn’t something man-made. In a geographic sense, Long Island is definitely an island.
Manhattan’s separation from the mainland by the Harlem river seems like a much more technical definition of island to me.
Name, coordinates, and topography, or it didn’t happen.
Hell of a dick move that would be. Meanwhile, Qatar defiantly sticks up as a thumb signaling “Up yours” in rude sign language. So there!
It’s not a very big lake:
Other sources say it only drains to the west in the spring when the water level is high.
And there is this other nearby creek: