Ouvrages du Libron
Encyclopedia
Ouvrages du Libron is a structure like no other on the Canal du Midi
. It allows the canal
to traverse the Libron River near Agde
in south-west France. At the point of intersection, the Libron is at sea-level and the Canal du Midi is slightly below so a traditional aqueduct was not an option. The problem was further exacerbated by the Libron's propensity to flash flood
up to twenty times a year. The problem was originally solved by the building of a pontoon aqueduct known as the Libron Raft which utilised a flush-decked barge
to protect the canal channel in times of flooding however this was replaced by the present structure in 1855.
was opened in 1681, a year after the death of its designer and implementer Pierre-Paul Riquet
. Between its opening and the creation of the Ouvrages du Libron, the Libron would periodically overflow and fill the canal with silt and debris. During periods of flooding, a special flush-walled barge would be placed in the canal, like a raft, with high walls on either end, forming a large walled area that would allow the Libron to flow over the canal without depositing its silt and trash. Canal traffic was unable to pass whilst the barge was in place and would have to wait for the flood to recede and the barge to be removed.
In 1855, the Ouvrages du Libron (Works of Libron) were built to better allow the two streams to coexist. The engineer Urbain Maguès designed a structure that allowed the Libron to be directed in such a way as to allow a canal boat to safely pass and to limit the mud and debris being deposited into the canal by the flooding river.
The river bed of the Libron was modified so that the stream would split into two paths as it approached the Canal du Midi. The paths crossed the canal through the Ouvrages du Libron, consisting of six "gates" on each side of a "protected area" 30.5 metres (100.1 ft) in length.
In a flooding situation, the Libron crosses the Canal du Midi in two bodies. Each body passes through the "works" through six gates opening into six sluice bodies. Each sluice is made up of three portions of walls. The river comes into the works, when the sliding gate is up, and is bounded by the stone walls of the "works", then by walls that have been slid into place over the canal body, and finally the stone walls on the exiting side.
The works allowed the river path nearest an approaching boat to be stopped for a period of time to allow a canal boat to cross through that area and rest for a time in the "protected area" between the two paths. The river path behind the boat would now be returned to flow and the path in front of the boat is halted. The boat can now cross this second path without interference.
The Libron River is in the French department of Hérault
in the Languedoc-Roussillon
region and flows into the Mediterranean.
Canal du Midi
The is a long canal in Southern France . The canal connects the Garonne River to the on the Mediterranean and along with the Canal de Garonne forms the Canal des Deux Mers joining the Atlantic to the Mediterranean. The canal runs from the city of Toulouse down to the Étang de Thau...
. It allows the canal
Canal du Midi
The is a long canal in Southern France . The canal connects the Garonne River to the on the Mediterranean and along with the Canal de Garonne forms the Canal des Deux Mers joining the Atlantic to the Mediterranean. The canal runs from the city of Toulouse down to the Étang de Thau...
to traverse the Libron River near Agde
Agde
Agde is a commune in the Hérault department in southern France. It is the Mediterranean port of the Canal du Midi.-Location:Agde is located on the river Hérault, 4 km from the Mediterranean Sea, and 750 km from Paris...
in south-west France. At the point of intersection, the Libron is at sea-level and the Canal du Midi is slightly below so a traditional aqueduct was not an option. The problem was further exacerbated by the Libron's propensity to flash flood
Flash flood
A flash flood is a rapid flooding of geomorphic low-lying areas—washes, rivers, dry lakes and basins. It may be caused by heavy rain associated with a storm, hurricane, or tropical storm or meltwater from ice or snow flowing over ice sheets or snowfields...
up to twenty times a year. The problem was originally solved by the building of a pontoon aqueduct known as the Libron Raft which utilised a flush-decked barge
Barge
A barge is a flat-bottomed boat, built mainly for river and canal transport of heavy goods. Some barges are not self-propelled and need to be towed by tugboats or pushed by towboats...
to protect the canal channel in times of flooding however this was replaced by the present structure in 1855.
History
The Canal du MidiCanal du Midi
The is a long canal in Southern France . The canal connects the Garonne River to the on the Mediterranean and along with the Canal de Garonne forms the Canal des Deux Mers joining the Atlantic to the Mediterranean. The canal runs from the city of Toulouse down to the Étang de Thau...
was opened in 1681, a year after the death of its designer and implementer Pierre-Paul Riquet
Pierre-Paul Riquet
Pierre-Paul Riquet was the engineer and canal-builder responsible for the construction of the Canal du Midi.-Background:...
. Between its opening and the creation of the Ouvrages du Libron, the Libron would periodically overflow and fill the canal with silt and debris. During periods of flooding, a special flush-walled barge would be placed in the canal, like a raft, with high walls on either end, forming a large walled area that would allow the Libron to flow over the canal without depositing its silt and trash. Canal traffic was unable to pass whilst the barge was in place and would have to wait for the flood to recede and the barge to be removed.
In 1855, the Ouvrages du Libron (Works of Libron) were built to better allow the two streams to coexist. The engineer Urbain Maguès designed a structure that allowed the Libron to be directed in such a way as to allow a canal boat to safely pass and to limit the mud and debris being deposited into the canal by the flooding river.
Operation
The Libron can be either a tranquil stream or a torrent caused by melting snow and heavy rains. During light volume, the Libron flows through a culvert beneath the intersection. During times of heavy runoff, the Libron carries significant amounts of silt and vegetation. The surface levels of the two streams are very similar during normal circumstances. This intersection at such close levels would not allow for an aqueduct or any other usual means of passing, one stream over the other.The river bed of the Libron was modified so that the stream would split into two paths as it approached the Canal du Midi. The paths crossed the canal through the Ouvrages du Libron, consisting of six "gates" on each side of a "protected area" 30.5 metres (100.1 ft) in length.
In a flooding situation, the Libron crosses the Canal du Midi in two bodies. Each body passes through the "works" through six gates opening into six sluice bodies. Each sluice is made up of three portions of walls. The river comes into the works, when the sliding gate is up, and is bounded by the stone walls of the "works", then by walls that have been slid into place over the canal body, and finally the stone walls on the exiting side.
The works allowed the river path nearest an approaching boat to be stopped for a period of time to allow a canal boat to cross through that area and rest for a time in the "protected area" between the two paths. The river path behind the boat would now be returned to flow and the path in front of the boat is halted. The boat can now cross this second path without interference.
The Libron River is in the French department of Hérault
Hérault
Hérault is a department in the south of France named after the Hérault river.-History:Hérault is one of the original 83 departments created during the French Revolution on 4 March 1790...
in the Languedoc-Roussillon
Languedoc-Roussillon
Languedoc-Roussillon is one of the 27 regions of France. It comprises five departments, and borders the other French regions of Provence-Alpes-Côte d'Azur, Rhône-Alpes, Auvergne, Midi-Pyrénées on the one side, and Spain, Andorra and the Mediterranean sea on the other side.-Geography:The region is...
region and flows into the Mediterranean.
External links
- http://www.kanaljene.com/dw/doku.php?id=kanal09:plankanal09 Map
- http://projetbabel.org/fluvial/images/libron_dessins.ppt French PowerPoint Presentation