Bormida (river)

The Bormida^[4] is so called by the pre-Roman Ligurian proto-form *bormo ('hot or bubbling water'), also linked to the names of the spring gods Bormō And Bormānus. The root *borm- in itself could have pre-Indo-European roots^[5] and to be, thus, connected with the language (or languages) lost of prehistoric inhabitants of Europe, who occupied Northern Italy before the possible arrival of Indo-Europei.

The Bormida spring auction includes four so-called "Bormide" minors (from the south to the north):

• the Bormida of Mallare, which is born from Mount Alto and the Bormida di Pallare, coming instead from Mount Settepani, both converging at the centers of San Giuseppe di Cairo and Bragno into a single watercourse called Bormida di Spigno;
• the Bormida of Millesimo, the main water course, which is born from with Scravaion (municipality of Castelvecchio di Rocca Barbena) and, once received after 90 km of course from the right the Bormida di Spigno near Bistagno (AL), becomes the Bormida proper, which flows into the Tanaro east of the city Alessandria.

The first part of Bormida, known as Bormida di Millesimo, was born in Liguria at about 800 m altitude from Rocca Barbena (Alpi Liguri). It initially flows into a very suggestive valley by bathing the centers of Bardineto and Calizzano (SV), enriching itself with the contribution of countless rii and water streams (from left on the Rio Black, the Rio di Valle and the Rio di Vetria; from right the stream Ash, the Rio delle Giaire, the Rio di Parasacco, the Rio di S. John and the Rio Secco) until it reaches near Murialdo (SV), where it enters the "Valley of the Three Kings" park, flowing between suggestive rock walls.

Once arrived at Acquafredda, a hamlet of Millesimo (SV), the river receives the first remarkable tributary: the Osiglietta stream, coming from Mount Settepani (1 386 m) and which, disembarked by an imposing dam, forms the picturesque lake of Osiglia^[6]. From here the river, with an almost doubled flow rate, continues flowing under the overpasses of the Turin-Savona motorway, and barred by a small dam flows through the municipality of Millesimo, also crossing the remains of an ancient medieval bridge. From this point, after receiving the flow of the Zemola torrent from the left, the Bormida di Millesimo ends its mountain course, opening up the road nestled at the foot of the rugged hills of the Langhe. It immediately crosses the municipality of Cengio where it is blocked by a small dam, after which it enters Piemonte following a very tortuous course through a suggestive wooded valley. It is home to a large number of towns all located in the province of Cuneo, including Saliceto, Camerana, Monesiglio, Gorzegno, Torre Bormida and Cortemilia.

At the latter center receives from the right the stream Uzzone (17.8 km and 1.7 m3/s), an important water course for its self-depurative process given the excellent quality of its waters (although scarce), and also famous for its unruly floods. From here he enters for a short time province of Asti flowing in the areas of high Monferrato bathing the municipalities of Vesime, Cessole, Loazzolo And Bubbio. At Monastero Bormida the river is overwhelmed by an ancient Romanesque bridge partly seriously injured during an exceptional flood in November 1994. In this section it has an annual average flow of about 9,2 m3/s and receives from the right the contribution of some small waterways including the two torrents named Tatorba, the Tatorba d'Olmo and that of Monastero. Continuing its run it gets wet Sessame to enter then province of Alessandria coming to the gates of Bistagno, where it receives the Bormida di Spigno from the right (7.6 m³/s, considered by many to be the eastern headwater branch of the Bormida river).

After this confluence, which takes place about 90 km from the springs of Rocca Barbena, the river changes its name by simply becoming Bormida. The water flow doubles at the same time on 17 m3/s annually while the valley expands to become sweeter and more regular. After wet Terzo and have received from the left the stream Bogliona and from the right the waters of the Erro stream (42 km and 4,6 m3/s), the river bathes the city of Acqui Terme, skirting the remains of an ancient Roman aqueduct and receiving the Rio Medrio from the left coming from the hills around the municipality of Alice Bel Colle. In the municipality of Visone then receives from the right the scarce affixes of the torrents Visone (0.8 m³/s) and Caramagna (0.6 m³/s). It then continues wetting Strevi, Rivalta Bormida And Cassine (where a dam perpetually removes 4 m³/s from the river to feed the Carlo Alberto Canal which then flows into the Tanaro at the Villa del Foro), then preparing to leave the findings of the Monferrato to enter the plain heavily clayed and with bends.

A Sezzadio, the river receives the small stream from the right Tired. after which crosses the municipality of Castellazzo Bormida where he joins at the Bridge of Maranzana with the Orba (73 km and c. 15.2 m3/s), its main right tributary, delimiting the boundary between the municipalities of Castellazzo Bormida, Alessandria And Frugarolo. From here on, with an average flow almost doubled again, the river laps the southern outskirts of Alessandria imposingly clayed by the tangential of Alessandria, to reach near the Pietra Marazzi where it flows from right into the river Tanaro.

The average annual flow rate of Bormida is (after confluence with the Orba) on 33 m3/s, a fairly important value. In fact, the flow of the river is heavily affected by rainfall so as to be classified as a rainwater course. The same is characterized by its extremely capricious character (in the lower course and in particular downstream of the confluence with the Orba, practically annual straripa), made of tumultuous floods (sometimes catastrophic), which occur mainly in the autumn or late spring season, during which the river can reach in a short time flow values even close to 3 000 m3/s. On the other hand, in summer, it suffers very marked due to the low rainfall and massive water levies carried out on the affluent Orba. On November 15, 2014 following very violent rains throughout the basin, in particular in the portion of the tributary Orba, which caused various flood events in Liguria and Piemonte, the river reached Alessandria a full record level never touched before equal to 9,20 meters, seriously fearing the occurrence of a flood in the city; record however then beaten on date 24 November 2019 with 9,39 meters following an exceptional wave of bad weather and especially the 4 October 2021 where he touched the 9,41 meters (with a peak of flow rate 3 000 m3/s) following an exceptional precipitation that affected the high portion of basin on the branch of Spigno and the effluents Erro and Orba.

To manage the waters of the river, together with those of the stream Uzzone, was formed Hydraulic Consortium of third category of the Bormida river and the Uzzone stream, based in Cortemilia; the institution was subsequently dissolved and liquidated pursuant to a decree of the Ministry of the Treasury dated 16 December 1994.^[7]

The river is quoted in the ode March 1821 by Alessandro Manzoni ("Who will be able of the Dora gem^[9] / della Bormida al Tanaro bride / of Ticino and the Selvosa Orba / scerner the confused wave in the Po».^[10])