Great Lakes these waterways is heavy. Pleasure boats can also enter or exit the Great Lakes by way of the Erie Canal and Hudson River in New York. The Erie Canal connects to the Great Lakes at the east end of Lake Erie (at Buffalo, New York) and at the south side of Lake Ontario (at Oswego, New York). In 2009, the lakes contained 84% of the surface freshwater of North America; if the water were evenly distributed over the entire continent's land area, it would reach a depth of 1.5 meters (5 feet). The source of water levels in the lakes
Aire and Calder Navigation Narrow Canals, and the Rochdale Canal. The Selby Canal connects to the Ouse, from where boats can travel upstream to reach York, Boroughbridge and Ripon, or downstream to the River Derwent. Beyond Goole are the Humber and hence Hull, Immingham, and the North Sea. The Sheffield and South Yorkshire Navigation, which can be reached via the New Junction Canal, forms a link with Doncaster, Rotherham and Sheffield to the south west, and the tidal River Trent at Keadby to the east. In the early 1600s, the River Aire was navigable to Knottingley, and boats carrying up to 30 tons traded