The Isère ( , ; ; ) is a
river
A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...
in the
Auvergne-Rhône-Alpes
Auvergne-Rhône-Alpes (; AURA) or ; or ; . is a Regions of France, region in southeast-central France created by the 2014 territorial reform of French regions; it resulted from the merger of Auvergne and Rhône-Alpes. The new region came into e ...
region
In geography, regions, otherwise referred to as areas, zones, lands or territories, are portions of the Earth's surface that are broadly divided by physical characteristics (physical geography), human impact characteristics (human geography), and ...
of southeastern
France
France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...
. Its source, a
glacier
A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...
known as the ''Sources de l'Isère'', lies in the
Vanoise National Park in the
Graian Alps
The Graian Alps (Latin language, Latin:: ''Alpes Graiæ'' ; ; ) are a mountain range in the western part of the Alps, and the name of an Roman province, Antic Rome province.
Etymology
The name ''Graie'' comes from the ''Graioceli'' Celts, Celt ...
of
Savoie
Savoie (; Arpitan: ''Savouè'' or ''Savouè-d'Avâl''; English: ''Savoy'' ) is a department in the Auvergne-Rhône-Alpes region, Southeastern France. Located in the French Alps, its prefecture is Chambéry. In 2019, Savoie had a population o ...
, near the ski resort in
Val-d'Isère
Val-d'Isère (, literally ''Valley of Isère (river), Isère'') is a Communes of France, commune of the Tarentaise Valley, in the Savoie Departments of France, department (Auvergne-Rhône-Alpes Regions of France, region) in southeastern France. It ...
on the border with
Italy
Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...
. An important left-bank tributary of the
Rhône
The Rhône ( , ; Occitan language, Occitan: ''Ròse''; Franco-Provençal, Arpitan: ''Rôno'') is a major river in France and Switzerland, rising in the Alps and flowing west and south through Lake Geneva and Southeastern France before dischargi ...
, the Isère merges with it a few kilometers north of
Valence.
Many riverside
communes have incorporated the Isère's name into their own, for example,
Sainte-Hélène-sur-Isère and
Romans-sur-Isère
Romans-sur-Isère (; ; Old Occitan: ''Romans'') is a Communes of France, commune in the Drôme Departments of France, department in southeastern France.
Geography
Romans-sur-Isère is located on the Isère (river), Isère, northeast of Valence, ...
. The
department of
Isère
Isère ( , ; ; , ) is a landlocked Departments of France, department in the southeastern French Regions of France, region of Auvergne-Rhône-Alpes. Named after the river Isère (river), Isère, it had a population of 1,271,166 in 2019. is likewise named after the river.
Etymology
The name ''Isère'' was first recorded under the form ''Isara'', which means "the impetuous one, the swift one." Not originally a
Celtic
Celtic, Celtics or Keltic may refer to:
Language and ethnicity
*pertaining to Celts, a collection of Indo-European peoples in Europe and Anatolia
**Celts (modern)
*Celtic languages
**Proto-Celtic language
*Celtic music
*Celtic nations
Sports Foot ...
word, it was very likely assimilated by the
Celts
The Celts ( , see Names of the Celts#Pronunciation, pronunciation for different usages) or Celtic peoples ( ) were a collection of Indo-European languages, Indo-European peoples. "The Celts, an ancient Indo-European people, reached the apoge ...
in ancient times. This word is related to the
Indo-European
The Indo-European languages are a language family native to the northern Indian subcontinent, most of Europe, and the Iranian plateau with additional native branches found in regions such as Sri Lanka, the Maldives, parts of Central Asia (e. ...
''*isərós'', meaning "impetuous, quick, vigorous," which is similar to the
Sanskrit
Sanskrit (; stem form ; nominal singular , ,) is a classical language belonging to the Indo-Aryan languages, Indo-Aryan branch of the Indo-European languages. It arose in northwest South Asia after its predecessor languages had Trans-cultural ...
''isiráḥ'' इसिरः à¸à¸´à¸ªà¸´à¸£à¸° with the same definition.
It was probably based on the reconstructed Indo-European root ''*eis(É™)'' (and not ''*is''), which incidentally has not been found in the
Celtic languages of the British Isles.
The word ''Isara'' figures in the etymology of many other river names, from ancient
Gaul
Gaul () was a region of Western Europe first clearly described by the Roman people, Romans, encompassing present-day France, Belgium, Luxembourg, and parts of Switzerland, the Netherlands, Germany, and Northern Italy. It covered an area of . Ac ...
and its neighboring lands. Examples of this are the
Ésera in
Spain
Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...
, the
Isar
The Isar () is a river in Austria and in Bavaria, Germany. Its source is in the Karwendel mountain range of the Alps. The Isar river enters Germany near Mittenwald and flows through Krün, Wallgau, Bad Tölz, Munich, and Landshut before reaching ...
in
Germany
Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...
, the small Franco-Belgian
Yser, or even the ancient name of the
Oise
Oise ( ; ; ) is a department in the north of France. It is named after the river Oise. Inhabitants of the department are called ''Oisiens'' () or ''Isariens'', after the Latin name for the river, Isara. It had a population of 829,419 in 2019.< ...
, ''Isara'' (the
French adjective ''isarien'' still exists in the language and continues to describe anything related to the Oise). In non-Celtic countries, we find the ''Isarco'', a river in Northern Italy, the ''Éisra'' and ''Istrà '' in
Lithuania
Lithuania, officially the Republic of Lithuania, is a country in the Baltic region of Europe. It is one of three Baltic states and lies on the eastern shore of the Baltic Sea, bordered by Latvia to the north, Belarus to the east and south, P ...
,
''
Jizera'' in the
Czech Republic
The Czech Republic, also known as Czechia, and historically known as Bohemia, is a landlocked country in Central Europe. The country is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the south ...
and ''
Usora'' in
Bosnia and Herzegovina
Bosnia and Herzegovina, sometimes known as Bosnia-Herzegovina and informally as Bosnia, is a country in Southeast Europe. Situated on the Balkans, Balkan Peninsula, it borders Serbia to the east, Montenegro to the southeast, and Croatia to th ...
.
Geography
The Isère's course measures
and runs through a wide variety of landscapes: from its source near the Italian border in the western Alps, it crosses the
Pays de Savoie and the
Tarentaise Valley, cuts between the
Chartreuse and
Belledonne mountain ranges, follows the
Vercors Massif, passes through the
Dauphiné
The Dauphiné ( , , ; or ; or ), formerly known in English as Dauphiny, is a former province in southeastern France, whose area roughly corresponded to that of the present departments of Isère, Drôme and Hautes-Alpes. The Dauphiné was ...
province
A province is an administrative division within a country or sovereign state, state. The term derives from the ancient Roman , which was the major territorial and administrative unit of the Roman Empire, Roman Empire's territorial possessions ou ...
, and finally meets with the Rhône at the foot of the
Vivarais
Vivarais (; ; {{cite web , url=http://www.columbia.edu/acis/ets/Graesse/orblatv.html , title = ORBIS LATINUS - Letter V) is a traditional region in the south-east of France, covering the ''département'' of Ardèche, named after its capital Vivier ...
.
Valleys
The upper valley of the Isère is called the
Tarentaise, and its middle valley the
Grésivaudan.
The lower valley constitutes a section of the (also called the ''Valentinois'') and is characterized by the river's deep, winding channel. Instead of widening its banks over time, the Isère has dug deeper into its
bed, forming stepped
fluvial terrace
Fluvial terraces are elongated Terrace (geology), terraces that flank the sides of floodplains and fluvial valleys all over the world. They consist of a relatively level strip of land, called a "tread", separated from either an adjacent floodplai ...
s. The valley has clearly defined borders and is relatively narrow, not exceeding in breadth.
The repetition of
alluvial deposition (during periods of
Quaternary glaciation
The Quaternary glaciation, also known as the Pleistocene glaciation, is an alternating series of glacial period, glacial and interglacial, interglacial periods during the Quaternary period that began 2.58 Year#SI prefix multipliers, Ma (million ...
) and
overdeepening
Overdeepening is a characteristic of Depression (geology), basins and valleys eroded by glaciers. An overdeepened valley profile is often eroded to depths which are hundreds of metres below the lowest continuous surface line (the thalweg) along a ...
(during
interglacial
An interglacial period (or alternatively interglacial, interglaciation) is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene i ...
periods), known as a
fluvioglacial system, led to the formation of several stepped
terraces in the lower Isère valley, like the one on which
Saint-Marcel-lès-Valence is built. This occurred through the massive accumulation of alluvium from the Isère on top of a bed of
Miocene
The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...
molasse. Today, these terraces still define the geography of the Plain of Valence.
Confluence
The Isère initially merges with one of the Rhône's diversion canals, built for
navigational
Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation includes four general categories: land navigation, ...
purposes, at
Pont-de-l'Isère. At the southern tip of
La Roche-de-Glun (a commune on an island formed by the canal), the
Isère Dam drains part of the water back into the Rhône and permits the Isère to continue its course alone until it passes through the
Bourg-lès-Valence Dam and reaches its final
junction with the Rhône.
Main Tributaries
(L) ''Left-bank tributary''; (R) ''Right-bank tributary''.
* (L) ,
** (R)
Doron de Champagny,
** (L) ,
** (L) ,
* (R)
Arly,
** (L)
Chaise,
** (L) ,
* (L)
Arc,
* (L)
Drac,
** (R) ,
** (L) ,
** (R) ,
** (L) ,
** (R)
Romanche,
** (L) ,
* (R) ,
* (R)
Morge,
** , , via the Morge Canal
* (L) ,
** (L) ,
* (R) ,
Cities on the Isère
*
Savoie
Savoie (; Arpitan: ''Savouè'' or ''Savouè-d'Avâl''; English: ''Savoy'' ) is a department in the Auvergne-Rhône-Alpes region, Southeastern France. Located in the French Alps, its prefecture is Chambéry. In 2019, Savoie had a population o ...
:
Val-d'Isère
Val-d'Isère (, literally ''Valley of Isère (river), Isère'') is a Communes of France, commune of the Tarentaise Valley, in the Savoie Departments of France, department (Auvergne-Rhône-Alpes Regions of France, region) in southeastern France. It ...
,
Bourg-Saint-Maurice,
Aime,
Moûtiers
Moûtiers (; Arpitan: ''Motiérs''), historically also called Tarentaise, is a commune in the Savoie department in the Auvergne-Rhône-Alpes region in Southeastern France.
Moûtiers is the main access point to the Les Trois Vallées ski regio ...
,
Albertville
Albertville (; Franco-Provençal, Arpitan: ''Arbèrtvile'') is a Subprefectures in France, subprefecture of the Savoie Departments of France, department in the Auvergne-Rhône-Alpes Regions of France, region in Southeastern France.
It is best k ...
,
Montmélian
*
Isère
Isère ( , ; ; , ) is a landlocked Departments of France, department in the southeastern French Regions of France, region of Auvergne-Rhône-Alpes. Named after the river Isère (river), Isère, it had a population of 1,271,166 in 2019. :
Pontcharra,
Grenoble
Grenoble ( ; ; or ; or ) is the Prefectures in France, prefecture and List of communes in France with over 20,000 inhabitants, largest city of the Isère Departments of France, department in the Auvergne-Rhône-Alpes Regions of France, region ...
,
Voreppe
*
Drôme
Drôme (; Occitan: ''Droma''; Arpitan: ''Drôma'') is the southernmost department in the Auvergne-Rhône-Alpes region of Southeastern France. Named after the river Drôme, it had a population of 516,762 as of 2019. :
Romans-sur-Isère
Romans-sur-Isère (; ; Old Occitan: ''Romans'') is a Communes of France, commune in the Drôme Departments of France, department in southeastern France.
Geography
Romans-sur-Isère is located on the Isère (river), Isère, northeast of Valence, ...
,
Pont-de-l'Isère,
La Roche-de-Glun
Hydrology

The length of the Isère is , and its
drainage basin
A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, ...
covers .
The
vertical profile of the river is made up of several zones:
* From its sources to
Sainte-Foy-Tarentaise (except for those sources having a slope of around 25%), the average slope of the Isère is 5.1%, in a more or less confined valley (forests, gorges, and higher up, grasslands).
* As far as
Moûtiers
Moûtiers (; Arpitan: ''Motiérs''), historically also called Tarentaise, is a commune in the Savoie department in the Auvergne-Rhône-Alpes region in Southeastern France.
Moûtiers is the main access point to the Les Trois Vallées ski regio ...
, the slope measures 1.18%.
* Before the river's confluence with the
Arly, its slope is only 0.53%.
* The slope decreases to 0.136% until
Grenoble
Grenoble ( ; ; or ; or ) is the Prefectures in France, prefecture and List of communes in France with over 20,000 inhabitants, largest city of the Isère Departments of France, department in the Auvergne-Rhône-Alpes Regions of France, region ...
.
* Downstream from Grenoble, it measures 0.1%.
The flow of the Isère was observed over a period of 58 years (between 1956 and 2015) at
Beaumont-Monteux in the
Drôme
Drôme (; Occitan: ''Droma''; Arpitan: ''Drôma'') is the southernmost department in the Auvergne-Rhône-Alpes region of Southeastern France. Named after the river Drôme, it had a population of 516,762 as of 2019. department, situated near the river's confluence with the Rhône. The
discharge of the river at Beaumont-Monteux measured .
The Isère's large seasonal fluctuations are typical of rivers fed in large part by
snowmelt, with springtime flooding raising the average monthly
discharge between and from April to July (peaking in May and June), and low water levels in autumn and winter, from August to February, with a minimum average monthly discharge of in September.
Generally speaking, this makes the Isère a very plentiful watercourse throughout the year.
However, the can drop to during a five-year dry spell,
which is very low.
On the other hand, severe flooding can result from rapid thaw or torrential autumn rain. In fact, and QIX 5 are and , respectively. QIX 10 is . QIX 20 reaches , while QIX 50 rises to ,
which is still moderate compared to other rivers in the south of France, like the
Tarn.
The highest instantaneous discharge on record was on September 16, 1960, while the highest daily value was on October 7 of the same year.
The depth of runoff for the Isère's drainage basin is annually, which is quite high above France's average and clearly superior to that of the Rhône's drainage basin ( in
Valence for a surface area of ). The specific discharge
Eaufrance Glossary on Water - Specific Flow
/ref> is 27.9 liters per second per square kilometer of drainage basin.
Gallery
Image:Isere à Daille.jpg, The Isère from La Daille, near Val-d'Isère
Val-d'Isère (, literally ''Valley of Isère (river), Isère'') is a Communes of France, commune of the Tarentaise Valley, in the Savoie Departments of France, department (Auvergne-Rhône-Alpes Regions of France, region) in southeastern France. It ...
Image:Moutiers.jpg, Moûtiers
Moûtiers (; Arpitan: ''Motiérs''), historically also called Tarentaise, is a commune in the Savoie department in the Auvergne-Rhône-Alpes region in Southeastern France.
Moûtiers is the main access point to the Les Trois Vallées ski regio ...
: the Isère and the cathedral
Image:200604 - Montmelian Pont Isere.JPG, The bridge on the Isère at Montmélian
Image:Pont Marius Gontard à Grenoble.JPG, The Isère leaving Grenoble
Grenoble ( ; ; or ; or ) is the Prefectures in France, prefecture and List of communes in France with over 20,000 inhabitants, largest city of the Isère Departments of France, department in the Auvergne-Rhône-Alpes Regions of France, region ...
Image:Romansvg.jpg, The Isère at Romans-sur-Isère
Romans-sur-Isère (; ; Old Occitan: ''Romans'') is a Communes of France, commune in the Drôme Departments of France, department in southeastern France.
Geography
Romans-sur-Isère is located on the Isère (river), Isère, northeast of Valence, ...
Image:Antoine Guindrand - Paysage de l'Isère - 1836.JPG, Antoine Guindrand
''Paysage de l'Isère'' sère landscape(1836)
See also
* List of rivers of France
This is a list of rivers that are at least partially in France. The rivers are grouped by sea or ocean. The rivers flowing into the sea are sorted along the coast. Rivers flowing into other rivers are listed by the rivers they flow into. Some rive ...
References
External links
*
{{DEFAULTSORT:Isere (river)
Rivers of France
Rivers of Drôme
Rivers of Isère
Rivers of Savoie
Rivers of Auvergne-Rhône-Alpes
Rivers of the Alps