Luretta


The Luretta is a torrent approximately long that flows entirely within the Province of Piacenza, a right-bank tributary of the Tidone.

Course

The Luretta originates in the municipal territory of Piozzano from the confluence of two branches: the Luretta di Monteventano, also known as Luretta Superiore, approximately long, with its source in the locality of Le Mogliazze on the slopes of Monte Lazzaro, near the border with the municipalities of Travo and Alta Val Tidone, and briefly marking the boundary between the municipalities of Piozzano and Travo, and the Luretta di San Gabriele, also known as Luretta Inferiore, approximately long, with its source near the hamlet of Groppo Arcelli, on the slopes of Monte Serenda.
The two branches join near the locality of Guadà, forming the Luretta proper, also known as Luretta Grande. In the initial stretch of its course, the torrent has an average slope of 76 per mille, which then decreases to 31 per mille.
It then passes through the town center of Piozzano, skirts the towns of Agazzano and Gazzola, and enters the municipality of Gragnano Trebbiense in the Po Valley, where the average slope stabilizes at 8 per mille.
Entering the municipal territory of Rottofreno, it flows into the Tidone torrent between Centora, a hamlet of Rottofreno, and Agazzino, a hamlet of Sarmato.

Tributaries

The Luretta has no particularly significant tributaries, receiving contributions from short torrents:
  • Torrents on the left bank: Rio Tarone; Rio Magnana
  • Torrents on the right bank: Rio Canto; Rio Sarturano; Rio Frate

    Hydrological regime

The torrent has a drainage basin of.
The Luretta exhibits a distinctly torrential river regime, with low water levels in summer and regular floods in spring and autumn. The average flow rate near Agazzano, calculated over the period 1991-2001, is 0.35 m³/s, increasing to 0.44 m³/s at Campremoldo Sopra in Gragnano and to 0.64 m³/s at the mouth in the Tidone.

History

The lower part of its course was involved in the Battle of the Trebbia, where, according to the account of the Roman historian Polybius, in December 218 BC, Hannibal inflicted a heavy defeat on the Roman consul Tiberius Sempronius Longus. The Carthaginian army, encamped near Tavernago, managed to trap the Roman infantry in the marshy bed of the torrent; the Numidian cavalry, supported by archers, decimated the Roman soldiers, only a third of whom managed to escape to the opposite bank of the nearby Trebbia river.
In 1750, the mouth of the Luretta into the Tidone was subject to reorganization and reclamation works that diverted the course of the Rio Lurone and Rio Roggia, then tributaries of the Luretta, connecting them to each other and then directing them to flow into the Tidone.