The remains of the Roman aqueduct – one of the best preserved of northern Italy – imposing and well-known, still stand just outside the contemporary residential area, along the Bormida stream and their construction can be dated back, as it is highly likely, to the first imperial times, perhaps even to the Augustan era (early 1st century AD).
Two separate large parts of the original above-ground structure still exist, respectively made up of seven and eight masonry pillars, quadrangular in shape (measuring between 180 and 300 cm on their side, in proportion to the vertical development of the same pillars) that become progressively smaller upwards with a series of regular offsets, with a height of about 15 metres. Diminished arches rest on the pillars (there are only four left) of 3.35 metres radius, above which ran the water pipe itself, which no longer exists. The route of the aqueduct covers a total length of about 12 kilometres, starting from the water catch basin located in the Lagoscuro area (today in the municipal district of Cartosio), through the Erro valley (along the orographic right side of the stream with the same name), Marchiolli region, – where it probably drew from other sources in the area of Rocca Sorda and where a long stretch of piping, in the suburb of La Maddalena, has been explored – up to the left bank of the Bormida river, with a total difference in height of about 50 metres. Most of the route is underground and consists of a duct of rectangular section – that in some of the parts examined is plastered or lined with “cocciopesto”* (height 120 cm, width 40 cm approximately) – with piers made of cement work (river pebbles or small blocks of sandstone bound with strong mortar) supporting a barrel round-arched vault, or, alternatively, a cover made of slabs of sandstone, horizontally overlapping or sloped on both sides.
In the end section, instead – starting from Marchiolli region, by the main road of Sassello, where perhaps there was also a tailing pond (piscina limaria**), necessary in order to purify the water from those impurities that it contained at the end of a long slope – just because of the need to cross the Bormida riverbed, the above-ground structure was built. Its remains have been preserved till nowadays, directly connected to the underground part of the duct. The original above-ground structure had to be made up, as a whole – calculating the space to go beyond and the centre distance – of at least forty pillars, through which the aqueduct made its monumental entry into the city. However, reliable archaeological data, with regard to the aqueduct course in its urban section, are missing, although, as significantly observed, the ideal continuation of the known route would directly lead to the hill on which the Castle is situated.
* Translator’s note cocciopesto: lime mortar with crushed pottery
** Translator’s note piscina limaria: catch basin of the dirty waters
The site is freely accessible any time.
The site is freely accessible without the payment of any ticket.