Arno

The Arno is a river in the Tuscany region of Italy. It is the most important river of central Italy after the Tiber.
The river originates on Mount Falterona in the Casentino area of the Apennines, and takes initially a southward curve. The river turns to the west near Arezzo passing through Florence, Empoli and Pisa, flowing into the Tyrrhenian Sea at Marina di Pisa. With a length of 241 kilometers, it is the largest river in the region. Its main tributaries are: the Sieve (60 kilometers), Bisenzio (49 kilometers), Ombrone, Era, Elsa, Pesa and Pescia. The drainage basin amounts to more than 8,200 km² and drains the waters of the following sub-basins:
* The Casentino, in the province of Arezzo, formed by the upper course of the river until the confluence with the Maestro della Chiana channel.
* The Val di Chiana, a plain dried in the 18th century, which, until the 18th century, was a marshy area tributary of the Tiber.
* The upper Valdarno, a long valley bordered from East by the Pratomagno massif and from West by the hills around Siena.
* The Sieve's basin, which flows in the Arno immediately before Florence.
* The middle Valdarno, with the plain including Florence, Sesto Fiorentino, Prato and Pistoia.
* The lower Valdarno, with the valley of important tributaries such as the Pesa, Elsa and Era and in which, after Pontedera, the Arno flows into the Tyrrhenian Sea. The river has a very variable discharge, ranging from minimum values such as 6 m³/s to more than 2,000. The mouth of the river was once near Pisa, but is now several kilometres westwards.
It crosses Florence, where it passes below the Ponte Vecchio and the Santa Trìnita bridge (built by Bartolomeo Ammanati, but inspired by Michelangelo). The river flooded this city regularly in historical times, the last occasion being the famous flood of 1966, with 4,500 m³/s after a rain of 437.2 mm in Badia Agnano and 190 millimetres in Florence, in only 24 hours.
The flow rate of the Arno is irregular. It is sometimes described as having a torrent-like behaviour, because it can easily go from almost dry to near-flood in a few days. At the point where the Arno leaves the Apennines, flow measurements can vary between 0.56 m³/s and 3,540 m³/s. New dams built upstream of Florence have greatly alleviated the problem in recent years.
A flood on November 4, 1966 collapsed the embankment in Florence, killing at least 40 people and damaging or destroying millions of works of art and rare books. New conservation techniques were inspired by the disaster, but even 40 years later hundreds of works still await restoration.

FIRENZE: PONTE VECCHIO

The bridge spans the Arno at its narrowest point where it is believed that a bridge was first built in Roman times,when the via Cassia crossed the river at this point.The Roman piers were of stone, the superstructure of wood. The bridge first appears in a document of 996. After being destroyed by a flood in 1117 it was reconstructed in stone but swept away again in 1333 save two of its central piers, as noted by Giovanni Villani in his Nuova Cronica.It was rebuilt in 1345, Giorgio Vasari recorded the tradition in his day, that attributed its design to Taddeo Gaddi,besides Giotto one of the few artistic names of the trecento still recalled two hundred years later. Modern historians present Neri di Fioravanti as a possible candidate. Sheltered in a little loggia at the central opening of the bridge is a weathered dedication stone, which once read Nel trentatrè dopo il mille-trecento, il ponte cadde, per diluvio dell' acque: poi dieci anni, come al Comun piacque, rifatto fu con questo adornamento. The Torre dei Mannelli was built at the southeast corner of the bridge to defend it.

The bridge consists of three segmental arches: the main arch has a span of 30 meters (98 ft) the two side arches each span 27 meters (88 ft). The rise of the arches is between 3.5 and 4.4 meters (11½ to 14½ feet), and the span-to-rise ratio 5:1.

It has always hosted shops and merchants who displayed their goods on tables before their premises, after authorization of the Bargello (a sort of a lord mayor, a magistrate and a police authority). The back shops (retrobotteghe) that may be seen from upriver, were added in the seventeenth century.

It is said that the economic concept of bankruptcy originated here: when a merchant could not pay his debts, the table on which he sold his wares (the "banco") was physically broken ("rotto") by soldiers, and this practice was called "bancorotto" (broken table; possibly it can come from "banca rotta" which means "broken bank"). Not having a table anymore, the merchant was not able to sell anything.

During World War II, the Ponte Vecchio was not destroyed by Germans during their retreat of August 4, 1944, unlike all other bridges in Florence.This was allegedly because of an express order by Hitler. Access to Ponte Vecchio was, however, obstructed by the destruction of the buildings at both ends, which have since been rebuilt using a combination of original and modern design.

In order to connect the Palazzo Vecchio (Florence's town hall) with the Palazzo Pitti, in 1565 Cosimo I de Medici had Giorgio Vasari build the famous Vasari Corridor above it. To enforce the prestige of the bridge, in 1593 the Medici Grand Dukes prohibited butchers from selling there; their place was immediately taken by several gold merchants. The corporative association of butchers had monopolised the shops on the bridge since 1442. A stone with an inscription from Dante (Paradiso xvi. 140-7) records the spot at the entrance to the bridge where Buondelmonte de' Buondelmonti was murdered on behalf of the Amidei, in 1215, initiating the urban fighting of the Guelfs and Ghibellines.