Actually, Ontario is the smallest of the Great lakes. Lake Ontario is the lowest, and last lake in the system, it empties into the Atlantic via the St. Lawrence River. The Great Lakes together make up the largest single system of fresh water in the world.By volume Ontario contains more water than any other body of fresh water, I'm almost positive of it. It's flush cycle is like 500 to 1000 years. It is VERY deep.
You have it confused with Lake Superior.