Glanum Dam

Glanum Dam
Location of Glanum Dam in France
Location	Glanum (Saint-Rémy-de-Provence), Bouches-du-Rhône, France
Coordinates	43°46′17″N 4°49′44″E / 43.77139°N 4.82889°E / 43.77139; 4.82889Coordinates: 43°46′17″N 4°49′44″E / 43.77139°N 4.82889°E / 43.77139; 4.82889
Opening date	1st century BC
Dam and spillways
Impounds	Vallon de Baume
Height	12 m
Length	18 m
Width (base)	3.9 m
Reservoir
Creates	Lac des Peiròu

The Glanum Dam, also known as the Vallon de Baume dam, was a Roman arch dam built to supply water to the Roman town of Glanum, the remains of which stand outside the town of Saint-Rémy-de-Provence in south-west France. It was situated south of Glanum, in a gorge that cut into the hills of Les Alpilles in the Roman province of Gallia Narbonensis. Dating to the 1st century BC, it was the earliest known dam of its kind. The remains of the dam were destroyed during the construction of a modern replacement in 1891, which now facilitates the supply of water to Saint-Rémy-de-Provence in the Bouches-du-Rhône region of France.

The remains of the Roman dam at Glanum were rediscovered in 1763 by Esprit Calvet with a more recent study published by S. Agusta-Boularot and J.L. Paillet in 1997. It is thought that the dam originally was composed of two curved parallel masonry walls, each around 1 metre (3.3 ft) thick and separated by a gap around 1.5 metres (4.9 ft) wide which was likely filled with earth and rubble. The cut stone blocks were held together by crampons and finished with Cordon joints designed to protect against water entry. At each end of the dam there was an abutment cut into the rock of the gorge. Overall the dam stood 6 metres (20 ft) high with a thickness of 3.5 metres (11 ft). The circumstances of its construction, including its dimensions and location in a steep-sided gorge, point towards it being a true arch dam. The dam collected water that was fed into an aqueduct that in turn supplied the Roman town of Glanum.

A modern arched gravity dam was constructed on the same site in 1891, destroying the remains of the Roman dam. The dam's reservoir is called in French the Lac du Peirou and is accessible via the Chemin du Barrage.