It was the middle of the thirteenth century, on the shores of a lake filled with stagnant water which " carries disease and death ", a basin without natural drainage, which gets its water supply from a much larger catchment area, measuring around 2 hectares. The place is unsafe and a carrier of disease. The four owners of the time therefore decided to drain it ...
Guillaume Raymond, Lord of Colombiers, Armingaud de Poilhes, Béranger d'Alzone and Bernard Scot thus gained around 430 hectares of farmland. Because we must not forget that at this time, there were more and more mouths to feed!
But they needed the authorisation of the Archbishop of Narbonne, Lord of Nissan who was " Lord and Master of all the waters of his diocese ”. On February 13, 1247, a charter in Latin granted the right to the four owners to carry out the work. They were carried out from 1250 to 1270: drainage ditches, wells and aqueduct and underground of 1 meters excavated under the " Malpas mountain ”(50 meters above sea level), so that the waters could be drained properly.
The work is remarkable! The visitor notices this by admiring this exceptional agrarian landscape in the shape of stars, a wheel or even a sun or even a heart, according to his perception. And it's since Montady Tower or the Oppidum d'Ensérune . 60 ditches, with a total length of 80 km, come together near Redondel, a circular ditch in the middle of the swamp. Each drain represents a plot which was called a point.
We can easily distinguish the main drainage canals of which there are 3: the large Maïres. That which is located in the axis of the Montady Tower, stretches as far as the entrance to the drainage tunnel, under Malpas hill. This Grande Maire is dug into the reverse slope. It goes from the central collector of the swamp, on the 20 side and arrives on the 18 side, at the entrance to the aqueduct. The water thus flows down a gentle slope and is evacuated towards the Poilhes and Capestang lakes.
It was from 1886 that the Montady pond could be supplied with water from the Canal du Midi with the "Malpas submersion canal" nicknamed the " Canalet" by the locals. This double network (peripheral network) of irrigation and gravity-assisted submersion completes the drainage network. New ditches, supplied by the water of the Canal du Midi, allowed the swamp to be submerged, plot by plot. “The phylloxera crisis at the end of the XNUMXth century decided the wine-growing vocation of the Montady pond. Thanks to the water from the Canal du Midi, two objectives are achieved: to improve the sanitation of salty soils, and to protect the vineyard against attacks from the phylloxera parasite, by flooding the land. »
In 1964, another irrigation system was installed, providing new crops with water, through spraying or drop-by-drop irrigation.
From the outset, the swamp was managed by all the co-owners. It was considered to be a real union association which was successively known as an Association Syndicale Libre (Private Property Owners Association), Association Syndicale Autorisée (Public Property Owners Association), then a Property Owners Association for the draining of Montady swamp.
The swamp drainage tunnel:
The Archbishop also gave his authorisation for the drainage of waters from Montady swamp onto his own land in Nissan, Poilhes and Capestang, " provided that the waters caused no damages ».
And that is how the drainage tunnel could be dug out. It was a real challenge! The 'qanat' procedure was used, a method that had been used in Persia (Iran today) since 500 BC. A qanat is a series of vertical access shafts, which allow access and ventilation, connected to a drainage channel built on a slight slope so that the water flows easily.
17 shafts are dug so that the earth can be removed and the channels can be formed. They also serve as markings at a time when the compass did not yet exist in the West. Most of these shafts are now blocked. The channel was 1 metres long, and 364 m wide on average with much narrower passages, and about 1,30 m high with places where you have to lower your head. It is a winding and irregular channel. It begins near the Railway line, at the entrance to the SNCF tunnel on the Colombiers side, and exits into the town of Nissan at a place called "les traoucats". A stream then carries the water to the old lake of Poilhes then to that of Capestang and it finally flows into the Aude river.
The Montady swamp drainage tunnel was built at a depth of 29 metres below Malpas mountain pass and 50 metres below the Canal du Midi.
Eight centuries after its construction, the flow still exists. And if that did not work, the Montady pond would be filled with water and would again create a sanitation problem.
THETourist Office, Maison du Malpas, a few meters away, will give you more information.