Does the Erie Canal, which connects the Hudson River with Lake Erie make northern New York, southern Quebec, all of New England, all of New Brunswick, and the non-island parts of Nova Scotia an island?
Does the Chicago Sanitary and Ship Canal make all of the eastern part of the US an island?
Does Russia's Unified Deep Water System make ...
The outer banks are, literally, a textbook example of what are known as Barrier Islands. They are thought to be formed through interactions between sediment undergoing longshore drift, coastal currents and seabed irregularities, but to spite a number of theories being put forward since the 19th Century we really don't understand their formation.
We do know ...
its the same way atolls form, sea level changes and tectonic plates move while the corals keep growing up as the land sinks. Any spot high enough for coral to survive can slowly grow in this way. they can end up hundreds of meters above the sea floor by the slow gradual process of growing coral.
I find a simple animation makes it easier to follow.
Cays are ...
It is possible to travel up the Tombigbee River to the Tennessee River. This is because parts of the Tombigbee River are man made.
The key part seems to be the "Divide Cut," a canal linking the Tennessee and Tombigbee Rivers.