How do the ships on StLawerence seaway bypass Niagara Falls?

Ships on the St. Lawrence Seaway do not bypass Niagara Falls, they bypass a section of the river encompassing both the Welland Canal and Niagara Falls.

Built between 1913 and 1932, the Welland Canal is made of 8 locks that span across Niagara Peninsula, connecting Lake Erie and Lake Ontario. Ships entering the canal are raised more than 515 feet from Lake Ontario, traverse several locks, and are lowered back down another 326 feet to Lake Erie, covering a total distance of 27.6 miles.