Bassin de Saint-Ferréol
Encyclopedia
The Bassin de Saint-Ferréol was created as the result of a large earth dam across the mouth of the valley of Laudot stream at St. Ferréol in the Montagne Noire
. It was originally proposed by Chevalier de Clerville and accepted by Pierre Paul Riquet as an integral part of the Canal du Midi
. Riquet needed to provide a sufficient water reservoir to allow the locks
to function year round, even in the dry summer season. The dam was begun on 15 April 1667 and was completed in four years. It was the first dam built specifically to supply water to a navigable canal and was by far the greatest single work of civil engineering undertaken during the building of the Canal du Midi
.
The dam has a crest length of 2560 ft (780.3 m), a maximum height of 105 ft (32 m), and a base thickness of more than 450 ft (137.2 m). Water may be drawn from the reservoir via a stone vaulted tunnel that penetrates the base of the dam. Silt can be removed from the floor of the reservoir through the tunnel. When filled to capacity, the reservoir contains some 180 million USgals (681,374.2 m³) of water.
Originally, the basin was to be fed by only the River Laudot. When this was deemed to be insufficient, other streams fed into what Riquet called the "rigole de la montagne
". Rigole is a diversionary channel. This stream would have included contributions from the River Alzau, River Vernassone, River Lampillon, River Lampy, and River Rieutort. The stream passed through the 132 yard, 9 ft diameter Cammazes
Tunnel on its way to the basin. The tunnel was built by the military engineer Marshall Sebastien Vauban
in 1686-87.
The entrance of the Laudot into the basin is split so that one portion goes into the basin and the other portion diverts around the basin and returns to the Laudot downstream of the dam. The waters released from the dam follow the downstream route of the Laudot until they join with the rigole de la plaine
at Les Thoumazes. The waters continue to the Bassin de Naurouze
before entering the canal itself.
Though Riquet took credit for the water supply provided by the basin, much of the knowledge required was provided by Pierre Campmas
, a fontainier, and François Andréossy
, an hydraulics engineer.
The lake lies in the three communes of Vaudreuille
(Haute-Garonne
), Les Brunels
(Aude
) and Sorèze
(Tarn).
Montagne Noire
* Not to be confused with the Montagnes Noires in Brittany.The Montagne Noire is a mountain range in central southern France. It is located at the southwestern end of the Massif Central in the border area of the Tarn, Hérault and Aude departments...
. It was originally proposed by Chevalier de Clerville and accepted by Pierre Paul Riquet as an integral part of the Canal du Midi
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...
. Riquet needed to provide a sufficient water reservoir to allow the locks
Locks on the Canal du Midi
There are 91 working locks on the Canal du Midi along its course from the Bassin du Thau on the Mediterranean coast to the junction with the Canal lateral a la Garonne in Toulouse. There are a further 13 locks on the La Nouvelle branch which runs through Narbonne to the Mediterranean at...
to function year round, even in the dry summer season. The dam was begun on 15 April 1667 and was completed in four years. It was the first dam built specifically to supply water to a navigable canal and was by far the greatest single work of civil engineering undertaken during the building of the Canal du Midi
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...
.
The dam has a crest length of 2560 ft (780.3 m), a maximum height of 105 ft (32 m), and a base thickness of more than 450 ft (137.2 m). Water may be drawn from the reservoir via a stone vaulted tunnel that penetrates the base of the dam. Silt can be removed from the floor of the reservoir through the tunnel. When filled to capacity, the reservoir contains some 180 million USgals (681,374.2 m³) of water.
Originally, the basin was to be fed by only the River Laudot. When this was deemed to be insufficient, other streams fed into what Riquet called the "rigole de la montagne
Rigole de la montagne
The rigole de la montagne was an important facet of the Canal du Midi, engineered by Pierre-Paul Riquet in southern France. The canal itself was built during 1666-1681. A critical aspect of the Canal du Midi was the supply of sufficient water to feed the canal. Each boat traversing its length...
". Rigole is a diversionary channel. This stream would have included contributions from the River Alzau, River Vernassone, River Lampillon, River Lampy, and River Rieutort. The stream passed through the 132 yard, 9 ft diameter Cammazes
Les Cammazes
Les Cammazes is a commune in the Tarn department in southern France.-Demography:-References:*...
Tunnel on its way to the basin. The tunnel was built by the military engineer Marshall Sebastien Vauban
Vauban
Sébastien Le Prestre, Seigneur de Vauban and later Marquis de Vauban , commonly referred to as Vauban, was a Marshal of France and the foremost military engineer of his age, famed for his skill in both designing fortifications and breaking through them...
in 1686-87.
The entrance of the Laudot into the basin is split so that one portion goes into the basin and the other portion diverts around the basin and returns to the Laudot downstream of the dam. The waters released from the dam follow the downstream route of the Laudot until they join with the rigole de la plaine
Rigole de la plaine
The critical feature of the Canal du Midi was to provide sufficient water to ensure that the lock system continued to function, even through the summer months. The first part of this endeavor was the rigole de la plaine . It carried water from the Sor River, at Pontcrouzet, to the...
at Les Thoumazes. The waters continue to the Bassin de Naurouze
Bassin de Naurouze
The Bassin de Naurouze is an octagonal holding tank, created during the building of the Canal du Midi as designed and built by Pierre-Paul Riquet. It was abandoned a few years after construction of the canal because of its recurrent silting problems. The flow of water from the...
before entering the canal itself.
Though Riquet took credit for the water supply provided by the basin, much of the knowledge required was provided by Pierre Campmas
Pierre Campmas
Pierre Campmas, fontainer of Revel, assisted Pierre-Paul Riquet in his earliest design of the Canal du Midi. He helped Riquet confirm that the valleys of the Montagne Noire could provide sufficient water for the canal and helped Riquet build model canal workings at Riquet's estate, Bonrepos....
, a fontainier, and François Andréossy
François Andreossy
François Andréossy was a French engineer, cartographer, and a citizen of Narbonne. He was born in Paris on 10 June 1633. After completing his engineering studies in Paris, Andréossy went to Italy in 1660 to study Italian canal technology in Lombardy and Padua. He returned from the trip and...
, an hydraulics engineer.
The lake lies in the three communes of Vaudreuille
Vaudreuille
Vaudreuille is a commune in the Haute-Garonne department in southwestern France.-Population:-References:*...
(Haute-Garonne
Haute-Garonne
Haute-Garonne is a department in the southwest of France named after the Garonne river. Its main city is Toulouse.-History:Haute-Garonne is one of the original 83 departments created during the French Revolution on March 4, 1790. It was created from part of the former province of Languedoc.The...
), Les Brunels
Les Brunels
Les Brunels is a commune in the Aude department in southern France.-Population:-References:*...
(Aude
Aude
Aude is a department in south-central France named after the river Aude. The local council also calls the department "Cathar Country".Aude is also a frequent feminine French given name in Francophone countries, deriving initially from Aude or Oda, a wife of Bertrand, Duke of Aquitaine, and mother...
) and Sorèze
Sorèze
Sorèze is a commune in the Tarn department in southern France.-External links:* *...
(Tarn).