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How do miter gates work in a canal lock?

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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.

Miter gates are the most common type of gate used in canal locks. They consist of two leaves that, when combined, are about 10 percent longer than the width of the lock.12

When the gates are open, the leaves are stored in recesses within the lock walls. To close them, the leaves turn approximately 60 degrees until they meet at the center of the lock, forming a V-shape that points upstream. This design allows the water pressure from the higher level to push the gates together, creating a secure seal.12

A critical operational requirement is that miter gates can only be opened once the water levels on both sides of the gate have been equalized. Depending on the size of the canal, these gates are operated either manually via lever arms or through hydraulic, mechanical, or electrical power systems. Historically, the invention of the mitered gate is often attributed to Leonardo da Vinci.12