The Miraflores Locks at night
The Miraflores Locks - the two-step set of Pacific-side locks - are at their present site because of the discovery of poor foundation materials at the original planned site at Sosa Hill. This meant that the Locks had to be built farther north at Miraflores - which also offered greater protection against the sea.
At Miraflores Locks, each lock chamber, except for the lower locks, has a set of intermediate gates. When a ship is small enough, these gates can be used on its progress through the lock, which reduces the size of the chamber and so conserves water.
The Miraflores Locks lower chamber gates are the tallest of any of the canal's locks because of the extreme variation in the Pacific tides. The electric floodlights were installed in 1963, and so allow the locks to be used 24 hours a day.
