Agde Round Lock
{{Short description|Lock on the Canal du Midi, France}}
{{Infobox waterlock
|lock_name = Agde Round Lock
|image= Agde bassin rond 3 portes.JPG
|caption= The round lock at Agde
|waterway = Canal du Midi
|country = France
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|county =
|maint = Voies navigables de France
|operation = Hydraulic
|first = c1676
|latest =
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|enda =
|distenda =
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| coordinates= {{coord|43.320253|N|3.467624|E|type:landmark_region:FR|display=inline,title}}
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The Agde Round Lock ({{langx|fr|L'Écluse Ronde d'Agde}}) is a canal lock on the Canal du Midi that connects to the Hérault River in Agde, France. It is almost unique because it is round, which allows a boat to turn around, and the fact that it has three sets of lock gates, each with a different water level. It was built in 1676 of volcanic stone and was originally 29.20 m in diameter, 5.20 m deep.
The lock is no longer round. It was expanded during a program begun in 1978 to expand locks to the Freycinet gauge to allow for barges up to 38.50 metres long.{{cite book | last = McKnight | first = Hugh | title = Cruising French Waterways, 4th Edition | publisher = Sheridan House| year = 2005 | pages =261, 272 | isbn = 978-0-7136-6638-0 }}
Originally, buildings in the area of the lock included an administration building, stables, shops, and a chapel.{{cite book | last = Rolt | first = L. T. C. | author-link = L. T. C. Rolt | title = From Sea to Sea | publisher = Ohio University Press | year = 1973 | isbn = 978-0-8214-0152-1 }}{{cite book | last = Mukerji | first = Chandra | title = Impossible Engineering: Technology and Territoriality on the Canal du Midi| publisher = Princeton University Press | year = 2009 | isbn = 978-0-691-14032-2 }}
The exits are to Béziers via the western section of the Canal du Midi, to Étang de Thau via the upper Hérault river and the eastern section of the Canal du Midi, and south to the Mediterranean via the lower Hérault river.{{cite web | url = http://www.tagweb.co.uk/french-waterways/0-waterways/midi.html | archive-url = https://archive.today/20130114033027/http://www.tagweb.co.uk/french-waterways/0-waterways/midi.html | url-status = dead | archive-date = January 14, 2013 | title = Canal du Midi | work = Afloat in France | publisher = grehanman guides | access-date = 2010-11-23 }}
A second French round lock can be found in the form of the now-disused Écluse des Lorraines, connecting the Canal latéral à la Loire with the River Allier.{{cite web | url = http://www.tagweb.co.uk/french-waterways/0-waterways/loire-lateral.html | title = Canal lateral a la Loire | work = Afloat in France | publisher = grehanman guides | access-date = 2010-11-24}}
Image:CdM - Ecluse Ronde d'Agde.jpg|Above, Béziers is shown to the right, Mediterranean on the top, and Etang de Thau to the left.
Image:Agde Round Lock post card.jpg|