Ancien aqueduc de Pontgouin à Versailles (également sur communes de Maintenon et Berchères-Saint-Germain)
MonumentHidden Treasure
Titanesque chantier de Louis XIV, l'aqueduc de Pontgouin à Versailles traverse la Beauce sur des kilomètres : un testament d'ingénierie royale resté inachevé, où la démesure du Roi-Soleil défie encore le paysage.
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History
In the heart of the Beauceron plain, between Chartres and Maintenon, stretches one of the great forgotten works of French heritage: the Pontgouin aqueduct, a colossal fragment of a hydraulic dream designed to supply water to the gardens of Versailles. Long levees of earth undulating across the fields, vaulted tunnels emerging from nowhere, locks asleep in their green setting - this abandoned site exudes a melancholic power that the most romantic ruins can barely match. What makes this monument truly unique is precisely its status as an unfinished work. Unlike the aqueduct at Maintenon, whose broken arches punctuate the Eure valley with a deliberate theatricality, the Pontgouin section can be read in a different way: in the earthworks, in the muted logic of the siphons and engineering structures buried beneath the grass. Attentive visitors will be able to decipher the ambitions of seventeenth-century engineers who wanted to bend an entire river to the will of a king. The visit is akin to a field survey. With your walking shoes on, you can walk along the embankments, spot the arched passageways under the country lanes, and stop in front of the Boizard dyke, whose discreet appearance conceals a design attributed to Vauban himself. The site can be traversed on foot or by bike, ideally over several kilometres, to grasp the dizzying scale of the undertaking. The setting plays a full part in the magic: the agricultural Beauce, often decried for its monotony, reveals here an unsuspected historical depth. In autumn, the great scorched earth levees stand out against a pale sky with an almost romantic austerity. In spring, the vegetation that colonises the engineering structures wraps them in a living mantle, paradoxically emphasising their robustness. Photographers and lovers of little-known history will find inexhaustible material here, far from the crowds that flock to Versailles or Maintenon.
Architecture
The Pontgouin aqueduct is not a single building, but a remarkably coherent linear hydraulic system. The construction principle is based on imposing earthworks - veritable linear dykes several metres high - that enable the canal to maintain a regular, gentle slope across the plateau between Chartres and Maintenon, irrespective of the natural relief. These earthworks, some ten metres wide at the base, form the visible backbone of the route over several kilometres. Buried in these embankments or crossing them, the engineering structures bear witness to sophisticated hydraulic engineering. Round arched tunnels, built of local limestone, allow roads and country lanes to pass under the canal. Siphons allow water to pass through the relief lines without breaking the continuity of the canal. Underground aqueducts cross the thalwegs of the small valleys that cut into the plateau, evacuating rainwater to prevent erosion of the earthworks. The Boizard dyke, a control structure attributed to Vauban, has a more massive ashlar design, combining retaining and flow control functions. All of the masonry is made of soft Beauce limestone, a local material that is easy to access, and is hammered with lime, as was common practice on royal building sites during the reign of Louis XIV.
Related Figures
Louis XIV — commanditaire du projet, dont la volonté de grandeur pour Versailles est à l'origine du chantierVauban (Sébastien Le Prestre de) — ingénieur militaire à qui l'on attribue la conception des écluses et de la digue de BoizardJules Hardouin-Mansart — architecte des Bâtiments du Roi, impliqué dans la coordination des grands travaux hydrauliques versaillaisLouvois (Michel Le Tellier de) — secrétaire d'État à la Guerre, organisateur de la réquisition des soldats-terrassiers pour le chantierAndré Le Nôtre — concepteur des jardins de Versailles dont les besoins en eau considérables justifièrent l'ensemble du projet hydraulique
