This is my 3rd attempt at this post. I am just going to lay out the bare facts and the importance of the Erie Canal.
The first canal was conceived in 1808. A series of hand dug shallow canals and locks connecting the Hudson River with Lake Erie. Originally 363 miles long, with 18 aqueducts and 83 locks, it was only 4 feet deep. It was all fed by gravity water flows and the shallow boats, pulled by mules, carried no more than 30 tons.
It was instantly successful. The price of moving a ton of goods west fell by 90%. The canal paid back the investment in the first year. It makes New York City the port it became, with goods now able to enter at New York City and travel up the Hudson, through the canal, and then across the Great Lakes. A series of cities and towns grow up, industries are built to use the canal in both directions, it is hard to overstate how important the canal was.
So important that eleven years after it opened a major reworking of the canal took place. Slightly shorter, the number locks reduced, the Enhanced Erie Canal could carry deeper and wider boats capable of 240 tons of cargo. It was the waterway that linked all the cities on the shores of the Great Lakes to the rest of the world.
At the turn of the 20th Century, there was complete reworking of the canal. It's not really called the Erie Canal anymore, it's the Barge Canal. Electrically operated locks, pumping stations, and larger, deeper locks were built, sometimes removing the original canal system, sometimes bypassing it. The boats became self propelled barges, carrying 3,000 tons, and the number of locks necessary was reduced to 36.
It was a major economic waterway that was slowly being overcome by the railroads as they carried more and more freight, but the opening of the St. Lawrence Seaway in 1957 really brought the Barge Canal traffic to an end. Large cargo ships could now enter the Great Lakes along the St. Lawrence River in a more direct route.
The Barge Canal and the remaining pieces of the Erie Canal belong mostly to tourists and boaters. The importance of the canal in the 19th Century is mostly forgotten. But in it's day, it opened the center of the country and made New York into the Empire State.
I picked this video because it's short, it shows a map, and it has some great images.