The decision to dig all the way

Today's Barge Canal includes Oneida Lake and the Seneca and Mohawk Rivers, but the designers of the original Erie decided to bypass them all with a completely man-made channel.  Animal power would propel the Erie's barges during its first century, and those animals needed a continuous towpath to walk on. It turned out to be a great decision, as mules didn't break down as steamboats would have, and the turbulence from steamboat paddlewheels would have seriously damaged the original Erie's fragile banks...

...plus, cargoes could make the whole trip without having to be transferred to and from lake vessels along the way (compare with the Canadian system above).  Also, unlike steam-powered craft, mule-hauled boats could keep moving at night, making the Erie a "24/7" proposition.