The Arno is a
river
A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of w ...
in the
Tuscany
it, Toscano (man) it, Toscana (woman)
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, demographics_type1 = Citizenship
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, demogra ...
region of
Italy
Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...
. It is the most important river of
central Italy
Central Italy ( it, Italia centrale or just ) is one of the five official statistical regions of Italy used by the National Institute of Statistics (ISTAT), a first-level NUTS region, and a European Parliament constituency.
Regions
Central I ...
after the
Tiber
The Tiber ( ; it, Tevere ; la, Tiberis) is the third-longest List of rivers of Italy, river in Italy and the longest in Central Italy, rising in the Apennine Mountains in Emilia-Romagna and flowing through Tuscany, Umbria, and Lazio, where ...
.
Source and route
The river originates on
Monte Falterona in the
Casentino area of the
Apennines, and initially takes a southward curve. The river turns to the west near
Arezzo passing through
Florence
Florence ( ; it, Firenze ) is a city in Central Italy and the capital city of the Tuscany Regions of Italy, region. It is the most populated city in Tuscany, with 383,083 inhabitants in 2016, and over 1,520,000 in its metropolitan area.Bilan ...
,
Empoli and
Pisa, flowing into the
Tyrrhenian Sea at
Marina di Pisa.
With a length of , it is the largest river in the region. It has many tributaries:
Sieve
A sieve, fine mesh strainer, or sift, is a device for separating wanted elements from unwanted material or for controlling the particle size distribution of a sample, using a screen such as a woven mesh or net or perforated sheet materia ...
at long,
Bisenzio at ,
Ombrone Pistoiese at , and the
Era,
Elsa,
Pesa, and
Pescia. The drainage basin amounts to more than and drains the waters of the following subbasins:
*The
Casentino, in the
province of Arezzo, formed by the upper course of the river until its confluence with the Maestro della Chiana channel.
*The
Val di Chiana
The Val di Chiana, Valdichiana, or Chiana Valley is an alluvial valley of central Italy, lying on the territories of the provinces of Arezzo and Siena in Tuscany and the provinces of Perugia and Terni in Umbria.
Geography
The Val di Chiana is ...
, a plain drained in the 18th century, which until then had been a marshy area tributary of the Tiber.
*The upper
Valdarno, a long valley bordered on the east by the
Pratomagno massif and on the west by the hills around
Siena
Siena ( , ; lat, Sena Iulia) is a city in Tuscany, Italy. It is the capital of the province of Siena.
The city is historically linked to commercial and banking activities, having been a major banking center until the 13th and 14th centur ...
.
*The Sieve's basin, which flows into 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
Ligurian Sea. The river has a very variable discharge, ranging from about to more than . The mouth of the river was once near
Pisa but is now several kilometres westwards.
It crosses
Florence
Florence ( ; it, Firenze ) is a city in Central Italy and the capital city of the Tuscany Regions of Italy, region. It is the most populated city in Tuscany, with 383,083 inhabitants in 2016, and over 1,520,000 in its metropolitan area.Bilan ...
, where it passes below the
Ponte Vecchio and the
Santa Trinita bridge (built by
Bartolomeo Ammannati
Bartolomeo Ammannati (18 June 151113 April 1592) was an Italian architect and sculptor, born at Settignano, near Florence. He studied under Baccio Bandinelli and Jacopo Sansovino (assisting on the design of the Library of St. Mark's, the ''Bibli ...
but inspired by
Michelangelo). The river
flood
A flood is an overflow of water ( or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are an area of study of the discipline hydrol ...
ed this city regularly in historical times, most recently in
1966, with after rainfall of in Badia Agnano and in Florence, in only 24 hours.
Before Pisa, the Arno is crossed by the Imperial Canal at La Botte. This water channel passes under the Arno through a tunnel, and serves to drain the former area of the
Lago di Bientina, which was once the largest lake in
Tuscany
it, Toscano (man) it, Toscana (woman)
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, population_blank1_title =
, population_blank1 =
, demographics_type1 = Citizenship
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, demographics1_title1 = Italian
, demogra ...
before its reclamation.
The flow rate of the Arno is irregular. It is sometimes described as having a torrentlike 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 . New
dam
A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use ...
s built upstream of Florence have greatly alleviated the problem in recent years.
The
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 decades later hundreds of works still await restoration.
Etymology
From Latin ''Arnus'' (Pliny, ''Natural History'' 3.50). The philologist
Hans Krahe related this toponym on a
paleo-European basis ''*Ar-n-'', derived from the
Proto-Indo-European root *''er-'', "flow, move".
Ecology
The Arno river has been strongly affected by non-native species: over 90% of fish species and 70% of macroinvertebrate species in the area around Florence are alien species.
These include the
European catfish,
channel catfish,
Crucian carp,
common bleak,
topmouth gudgeon,
New Zealand mud snail
The New Zealand mud snail (''Potamopyrgus antipodarum'') is a species of very small freshwater snail with a gill and an operculum. This aquatic gastropod mollusk is in the family Tateidae.
It is native to New Zealand, where it is found throug ...
,
and
killer shrimp.
The
mud crab
Mud crab may refer to any crab that lives in or near mud, such as:
*'' Scylla serrata''
*'' Scylla tranquebarica''
*'' Scylla paramamosain''
*'' Scylla olivacea''
*Members of the family Panopeidae, such as '' Panopeus herbstii''
*Members of the ...
has been found in the river near Pisa.
Uses and human impacts
Water from the Arno drainage basin is used for drinking water, irrigation, and firefighting.
Citizens in the central part of the drainage basin also identified flood control, support for biodiversity, fisheries, and cultural value as other services that the river provides.
There is the risk that flooding will jeopardize these
ecosystem service
Ecosystem services are the many and varied benefits to humans provided by the natural environment and healthy ecosystems. Such ecosystems include, for example, agroecosystems, forest ecosystem, grassland ecosystems, and aquatic ecosystems. ...
s, as 9% of wastewater treatment plants, 10% of landfills or other waste sites, and 4.5% of contaminated sites are at high risk of flooding, which would produce hotspots of pollution.
Gallery
File:Arno_river.jpg, The Arno in Florence
File:Arno River in Pisa.honeydew.jpg, The Arno in Pisa, near the Ponte della Fortezza (Fortress Bridge)
File:Firenze.Arno.jpg, Banks of the Arno, seen from the Ponte Vecchio (Old Bridge), Florence
Florence ( ; it, Firenze ) is a city in Central Italy and the capital city of the Tuscany Regions of Italy, region. It is the most populated city in Tuscany, with 383,083 inhabitants in 2016, and over 1,520,000 in its metropolitan area.Bilan ...
File:Arno_Mouth_Italy_aerial_view.jpg, Mouth of the Arno in Marina di Pisa
File:Florence Arno 180.jpg, The Arno in Florence
Florence ( ; it, Firenze ) is a city in Central Italy and the capital city of the Tuscany Regions of Italy, region. It is the most populated city in Tuscany, with 383,083 inhabitants in 2016, and over 1,520,000 in its metropolitan area.Bilan ...
, 180 degree view: the Uffizi
The Uffizi Gallery (; it, Galleria degli Uffizi, italic=no, ) is a prominent art museum located adjacent to the Piazza della Signoria in the Historic Centre of Florence in the region of Tuscany, Italy. One of the most important Italian museums ...
Gallery is straight across and the Ponte Vecchio is to the left
File:Florence at night.jpg, The Arno in Florence
Florence ( ; it, Firenze ) is a city in Central Italy and the capital city of the Tuscany Regions of Italy, region. It is the most populated city in Tuscany, with 383,083 inhabitants in 2016, and over 1,520,000 in its metropolitan area.Bilan ...
at night
File:Ponte amerigo vespucci.JPG, The Ponte Amerigo Vespucci
Ponte Amerigo Vespucci is a bridge over the Arno River in Florence, Italy and named after Florence-born explorer Amerigo Vespucci. It joins the Lungarno Amerigo Vespucci to the Lungarno Soderini. To the east is the Ponte alla Carraia.
This bridg ...
(Amerigo Vespucci Bridge)
References
External links
Basin Authority of the Arno
{{Authority control
Rivers of Italy
Rivers of Tuscany
Geography of Florence
Geography of Pisa
Rivers of the Province of Arezzo
Rivers of the Province of Florence
Rivers of the Province of Pisa
Rivers of the Province of Prato
Rivers of the Apennines
Drainage basins of the Tyrrhenian Sea