Acquedotto romano di Acqui Terme

Of all the Roman structures in Piedmont, none survives as well as the aqueduct of Acqui Terme. Two stretches of stone pylons, up to fifteen metres tall, still stride across the ground near the Bormida river — the visible end of a water line that once ran some twelve kilometres through the Erro valley to serve the Roman spa town.

Why it matters

Roman aqueducts are often known through buried conduits or surviving arcades; Acqui's is a rare case where the pylons still make the engineering legible. The line was built in the early imperial age, probably under Augustus, at the beginning of the first century AD, and the municipal portal describes the surviving monument as the best-preserved Roman structure of its kind in Piedmont and among the most significant aqueduct remains in northern Italy. For the ancient town of Aquae Statiellae — a community whose entire identity rested on its hot springs — a dependable supply of fresh water from the hills was civic infrastructure of the first order, complementing rather than replacing the thermal sources.

What to notice

Two sections of the elevated structure survive, carrying seven and eight pylons respectively. The piers stand on quadrangular bases between 1.8 and 3 metres per side, their footprint widening with height, and taper upward in regular offsets — a deliberate stability device, not erosion. In the best-preserved stretch the pylons rise about fifteen metres and still support four large segmental arches with a radius of 3.35 metres; the water channel they once carried has vanished. Set against the original elevated crossing, which must have counted at least forty pylons, the remains give a vivid sense of scale. The masonry uses river pebbles and sandstone set in mortar, typical of regional Roman building practice. The water line began at a catch basin at Lagoscuro, in Cartosio's territory, followed the Erro valley for about twelve kilometres — probably supplemented by the Rocca Sorda springs — and crossed to the left bank of the Bormida where the pylons stand.

Context and history

The aqueduct belongs to the first great building phase of Roman Aquae Statiellae, when the settlement raised to municipal status acquired its forum, theatre, temples and baths. Most of the conduit was underground: a rectangular duct of about 120 by 40 centimetres, built of cement work and in places lined or plastered with cocciopesto, covered with barrel vaults or sandstone slabs. A stretch of pipe explored at La Maddalena and a probable settling basin at Marchiolli — where impurities were allowed to settle before the final run — complete the technical picture, with an overall drop of only about fifty metres across the whole route, a remarkably gentle gradient. Where the line ended in town is not securely established: no reliable archaeological data exist for the urban stretch, though the ideal continuation points toward the castle hill. The surviving pylons near the river stand just below the nineteenth-century Ponte Carlo Alberto, placing Roman and modern infrastructure in the same landscape.