Does a canal cutting across an isthmus make an island?

Factual Questions
21

It’s more like a decent-sized pond - but gains lots of style points by draining into two different oceans.

And it does that with style: The water that flows out to the east ends up in the Pacific Ocean (via Snake and Columbia Rivers); the water that flows west goes to the Atlantic (via Madison, Missouri and Mississippi Rivers).

22

The connected waters flow coast to coast. Natural streams, mind you, per the definition of island. That means everything north (or south? I dunno) of those streams is the world’s biggest island. Eat your heart out, Greenland.