Agde round lock

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Round lock in Agde: in
front - from Béziers ; behind - to the Étang de Thau ; right - to the Mediterranean .
The lock basin was enlarged in the rear left sector to accommodate longer ships in the 1970s.
Double lock gate in the direction of Béziers to block a higher (ascent to Herault) or lower water level (descent to Agde) in the lock chamber,
closed position of the left gate is shown schematically
Original plan, 17th century:
The quarter sector at the bottom left was enlarged to accommodate longer ships in the 1970s.

The round lock of Agde (French: Écluse ronde d'Agde ) is a lock in the Canal du Midi near Agde .

It was built in 1676 and is the only boiler lock with more than two connections in operation in France. The third connection leads into a branch canal that leads to the lower reaches of the Hérault River and thus a short route to the Mediterranean Sea .

In the course of the Canal du Midi from the top of the Naurouze to the Étang de Thau , this lock covers an intermediate ascent. This results from the Hérault dammed with a weir . The Hérault is crossed at this level, which is higher than that of the incoming channel. According to the lock table, the rise is a maximum of 44 cm. The corresponding descent takes place in the Prades lock on the other side of the river.

At the connection to and from Béziers (lower picture), the Canal du Midi is either upstream or downstream. It is to be locked against a higher (drive to the Étang de Thau) or a lower water level (drive to the Mediterranean Sea) in the lock chamber. For the second case, the lock has a second (outer, left in the picture) double-leaf revolving gate that is closed when the lock is down and holds back the water in the Canal du Midi. The first (inner, on the right in the picture) gate prevents the water from flowing out of the lock chamber when it is locked upwards into the dammed Hérault. The reason for the second gate is that the traditional double-leaf swing gates can only lock in one of two directions. Together they form an arrow that points against the direction of flow to be prevented.

In the course of the expansion of the canal that began in the 1970s, the round lock was enlarged. The chamber was expanded over about a quarter of the circular enclosure. In this sector the longer ships are turned. The three lock gates have remained largely unchanged. Since the extended quarter sector is also bounded by a circle, the round character of the lock was hardly disturbed by the measure.

literature

  • Chandra Mukerji: Impossible Engineering: Technology and Territoriality on the Canal du Midi. Princeton University Press, Princeton 2009.

Web links

Commons : Agde round sluice  - collection of images, videos and audio files

Individual evidence

  1. ^ Michel Cotte: Le Canal du Midi - “Merveille de Europe” , Belin-Herscher, 2003, ISBN 2-7011-2933-8 , p. 64

Coordinates: 43 ° 19 ′ 13 ″  N , 3 ° 28 ′ 3 ″  E