Barbegal

The Barbegal aqueduct and mill is a Roman watermill complex located on the territory of the commune of Fontvieille, near the town of Arles, in southern France. The complex has been referred to as "the greatest known concentration of mechanical power in the ancient world". Another similar mill complex existed also on the Janiculum in Rome, and there are suggestions that more such complexes exist at other major Roman sites, such as Amida.

The site of the Barbegal aqueduct and mills is on a Roman aqueduct that was built to supply drinking water from the mountain chain of the Alpilles to the town of Arles, France (then called Arelate) on the Rhône River. Twelve kilometers north of Arles, at Barbegal, near Fontvieille, where the aqueduct arrived at a steep hill, the aqueduct fed two parallel sets of eight water wheels to power a flourmill. There are two aqueducts which join just north of the mill complex, and a sluice which enabled the operators to control the water supply to the complex. The mill consisted of 16 waterwheels in two separate descending rows built into a steep hillside. There are substantial masonry remains of the water channels and foundations of the individual mills, together with a staircase rising up the hill upon which the mills are built. The mills apparently operated from the end of the 1st century until about the end of the 3rd century. The capacity of the mills has been estimated at 4.5 tons of flour per day, enough to supply bread for as many as 10,000 of perhaps 30-40,000 inhabitants of Arelate at that time. It is thought that the wheels were overshot water wheels with the outflow from the top driving the next one down and so on, to the base of the hill.

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