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How did the Welland Canal overcome the height difference between Lake Ontario and Lake Erie?

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View of Utrecht's Oude Gracht canal lined with historic brick buildings, arched doorways at water level, and boats moored along the canal edge in the Netherlands. — canals and inland waterways The *Oudegracht* (Old Canal), Utrecht, Netherlands.

The Welland Canal overcomes the 100-metre (327-foot) elevation difference between Lake Erie and Lake Ontario through the use of eight locks.

These locks function as enclosed basins with movable gates at each end, allowing vessels to be raised or lowered between the different water levels of the two lakes. When a vessel enters a lock, the chamber is filled or emptied using sluices—often located on culverts within the lock structure—to match the water level of the next section of the canal. Once the water levels are equalized, the gates are opened to allow the vessel to proceed to the next level. This system was necessary because the natural connection between the lakes, the Niagara River, contains impassable falls and rapids.123