A reader had some questions:
“Where do we draw the line between island and peninsula with regard to man made structures?”
There is no clear line, as many parts of land have manmade water cutting them off.
“Prince Edward County on Lake Ontario was a peninsula, but did construction of the Murray Canal 100 years ago make it an island? (It has a couple of swing bridges over the canal and a high fixed bridge from Belleville, Ontario.)”
Probably not. Ratios are important, and the canal is very narrow compared to the peninsula. Indeed, it cannot even be discerned on this view that takes in the whole land mass.
“Prince Edward Island was connected by a long high bridge to the mainland 7 years ago. Should it be considered a peninsula?”
Bridges do not change the fact that an island is surrounded by water, so they do not erase an island’s fundamental nature. It is more a sort of domestication.
“Cape Breton Island is connected by a causeway to the rest of Nova Scotia.”
A solid causeway is more of a threat, but the Canso Causeway is broken by locks.
“Does the Corinth Canal in Greece make the Peloponnesus an island?”
Opinion is also important, and people have not decided that this is the case. Also, on a full view of the Peloponnesus it does not appear to be an island.
“Does the causeway to Singapore make it a peninsula?”
The Johor-Singapore Causeway is very small compared to the size of the island. Still, if it is solid all the way through, it does compromise Singapore’s status as a true island.
“Or is the natural state of the land mass the arbitrator of the land mass? I think you mentioned a former island in the Aral Sea or the Caspian as a peninsula due to the drop in water level. But was that not the result of irrigation?”
Human actions create and destroy islands all the time — what matters is whether a body of land surrounded by water results.
“Rene Lavasseur in Quebec exists as an island only because of the damming of the Manicaguan Reservoir.”
René-Levasseur is nonetheless a real island, as this view of the Manicouagan Reservoir shows. It is, incidentally, the largest island created by human action.