What Are the Panama Canal Locks?
The Panama Canal locks are a kind of water “stairway” that crosses the Isthmus of Panama and connects the Atlantic and Pacific Oceans. A ship sailing from the Atlantic enters into a set of locks. Water is let into the lower lock, and the ship is lifted to the water level of the next higher lock.
When the gates to the last lock are opened, the ship sails across a lake and into another set of locks that lowers the ship to the water level of the Pacific Ocean. Before the Panama Canal was built, ships had to sail the long journey around South Africa.
The original canal had a total of six steps (three up, three down) for a ship’s passage. The total length of the lock structures, including the approach walls, is over 1.9 miles (3 km). The locks were one of the greatest engineering works ever to be undertaken when they opened in 1914. No other concrete construction of comparable size was undertaken until the Hoover Dam, in the 1930s.
There are two independent transit lanes, since each lock is built double. The size of the original locks limits the maximum size of ships that can transit the canal; this size is known as Panamax.
Construction on the Panama Canal expansion project, which included a third set of locks, began in September 2007. Commercial operation on 26 June 2016. The new locks allow transit of larger, New Panamax ships, which have a greater cargo capacity than the previous locks were capable of handling.
Each lock chamber requires 26,700,000 US gal (101,000 m3) of water to fill it from the lowered to the raised position; the same amount of water must be drained from the chamber to lower it again.
Embedded in the side and centre walls are three large water culverts that are used to carry water from the lake into the chambers to raise them, and from each chamber down to the next, or to the sea, to lower them.
These culverts start at a diameter of 22 ft (6.71 m) and reduce to 18 ft (5.49 m) in diameter, large enough to accommodate a train. Cross culverts branch off from these main culverts, running under the lock chambers to openings in the floors.
There are fourteen cross culverts in each chamber, each with five openings; seven cross culverts from the sidewall main culverts alternate with seven from the centre wall culvert.
The water is moved by gravity and is controlled by huge valves in the culverts. Each cross culvert is independently controlled. A lock chamber can be filled in as little as eight minutes. There is significant turbulence in the lock chamber during this process.