Dranse (Haute-Savoie)
Encyclopedia
The Dranse is a French
river
in the department of Haute-Savoie
, that empties into Lake Geneva
.
The name "Dranse" comes from the former Drantia, based on the hydronym
dur-, dora and the suffix -antia.
, which converge 9 to 10 km (5.6 to 6.2 mi) upstream from the delta
:
The Dranse d'Abondance is considered the higher-ordered stream of the Dranse. The Dranse de Morzine is consequently considered its tributary
, according to Sandre
, the French National Service for Water Data and Common Repositories Management.
The Dranse empties into Lake Geneva
and forms a delta
, which is integrated into the Delta de la Dranse National Nature Reserve
, situated to the east of the commune of Thonon-les-Bains
, which although small at an area of 53 hectares (131 acre), offers an incomparable botanic diversity
.
The river is 49.1 kilometres (30.5 mi) long.
. Its discharge
was observed for a period of 97 years (1906–2003) in Reyvroz
, a locality in the department of Haute-Savoie
situated on the southern bank of Lake Geneva
at the same elevation
as its outlet. The drainage basin
for the river is in its totality 495 square kilometre, which is not quite three times the surface area
of the city of Paris
.
The annual average discharge of the river at Reyvroz is 20.1 cubic metre per second.
The Dranse is a typical seasonal river regime
, with depends slightly on a small rain
component. It exhibits sharply delineated seasonal fluctuations in discharge, which is characteristic of Alpine waterbodies. High flows occur in the springtime and are attributed to snowmelt
. These accompany average monthly discharges of around 30 cubic metre per second from April to June (the maximum being reached in May). At the end of June, discharge rates sharply drop while the volume moves downstream. From the end of July to the end of February discharge is continuous, fluctuating between 12.7 cubic metre per second, with a low of 12.7 cubic metre in August, and a small "peak" cut in November, linked to the autumn
al rain. However, these fluctuations are much more pronounced over short periods and depend on the year.
During times of low water, the low water discharge can fall as low as 2.5 cubic metre per second, in the case of a dry quinquennial period, and although low, it is considered normal in the regions of the Alps and Prealps.
In terms of flood
s which, although uncommon, can be very important, measures with certain "eau du midi". The maximum instantaneous discharge for a two-year (P2) and five-year (P5) flood events
are 180 cubic metre respectively. The ten-year flood event (P10) is 250 cubic metre per second, the twenty-year flood event (P20) 270 cubic metre, and the fifty-year flood (P50) 310 cubic metre.
The highest instantaneous flow recorded by the Reyvroz station was 273 cubic metre per second on the , while the maximum daily value was 229 cubic metre per second on . For comparison, the June 1963 value is comparable to a vicennial flood event, and is thus considered not that exceptional.
The discharge volume of Dranse is augmented by the abundant precipitation
in the northern Alps. The runoff curve number for its drainage basin is 1285 millimetres (50.6 in) annually, which elevated, is three times greater than the average for all of France. The specific discharge (Qsp) of the river reaches 40.7 litres (10.8 US gal) per second and square kilometer of the basin.
website Banque Hydro - Station V0334010 - La Dranse à Reyvroz (Bioge) (Synthèse) (the "Station en service" is unchecked)
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
river
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...
in the department of Haute-Savoie
Haute-Savoie
Haute-Savoie is a French department in the Rhône-Alpes region of eastern France. It borders both Switzerland and Italy. The capital is Annecy. To the north is Lake Geneva and Switzerland; to the south and southeast are the Mont Blanc and Aravis mountain ranges and the French entrance to the Mont...
, that empties into Lake Geneva
Lake Geneva
Lake Geneva or Lake Léman is a lake in Switzerland and France. It is one of the largest lakes in Western Europe. 59.53 % of it comes under the jurisdiction of Switzerland , and 40.47 % under France...
.
The name "Dranse" comes from the former Drantia, based on the hydronym
Hydronym
A hydronym is a proper name of a body of water. Hydronymy is the study of hydronyms and of how bodies of water receive their names and how they are transmitted through history...
dur-, dora and the suffix -antia.
Geography
The Dranse is formed from the combination of three mountainous rivers originating from the peaks of the upper Chablais AlpsChablais Alps
The Chablais Alps are a mountain range in the western Alps. They are situated between Lake Geneva and the Mont Blanc Massif. The Col des Montets separates them from the Mont Blanc Massif in the south, and the Rhône valley separates them from the Bernese Alps in the east.The Chablais Alps are...
, which converge 9 to 10 km (5.6 to 6.2 mi) upstream from the delta
River delta
A delta is a landform that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river...
:
- To the east, the Dranse d'AbondanceDranse d'AbondanceThe Dranse d'Abondance is a small river in the French department of Haute-Savoie, a sub-tributary of the Rhône via the Dranse de Morzine and the Dranse.- Geography :...
irrigates the Val d'Abondance and passes through the communes of Abondance and ChâtelChâtelChâtel is a commune in the Haute-Savoie department in the Rhône-Alpes region in south-eastern France.It is situated in the northern French Alps on the French/Swiss border and is a popular ski resort...
; - To the south, the Dranse de Morzine passes through MorzineMorzineMorzine is a commune in the Haute-Savoie department in the Rhône-Alpes region in eastern France with panoramic mountain views, modern ski facilities and hotels and restaurants. The ski resort of Avoriaz is located on the territory of the commune...
, Saint-Jean-d'AulpsSaint-Jean-d'AulpsSaint-Jean-d'Aulps is a commune is the Haute-Savoie department in the Rhône-Alpes region in south-eastern France. Situated in the heart of the Vallée d'Aulps, as well as being the home to an active farming community, it is popular with holiday-makers in the Summer, for walking, and in the Winter...
and the Gorges du Pont-du-Diable; - To the west, the Brevon, also called the Dranse de Bellevaux, originates from Roc d'Enfer and passes through Lac de VallonLac de VallonLac de Vallon is a lake at Bellevaux in the Haute-Savoie department of France. The lake formed in 1943 when a landslide blocked the course of the Brévon river....
and the villages of Bellevaux, VaillyVaillyVailly may refer to the following places in France:*Vailly, Aube, a commune in the Aube department*Vailly, Haute-Savoie, a commune in the Haute-Savoie department...
and ReyvrozReyvrozReyvroz is a commune in the Haute-Savoie department in the Rhône-Alpes region in south-eastern France.-References:*...
.
The Dranse d'Abondance is considered the higher-ordered stream of the Dranse. The Dranse de Morzine is consequently considered its tributary
Tributary
A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...
, according to Sandre
Sandre
Sandre stands for Service d’administration nationale des données et des référentiels sur l’eau, [French National Service for Water Data and Common Repositories Management]...
, the French National Service for Water Data and Common Repositories Management.
The Dranse empties into Lake Geneva
Lake Geneva
Lake Geneva or Lake Léman is a lake in Switzerland and France. It is one of the largest lakes in Western Europe. 59.53 % of it comes under the jurisdiction of Switzerland , and 40.47 % under France...
and forms a delta
River delta
A delta is a landform that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river...
, which is integrated into the Delta de la Dranse National Nature Reserve
Delta de la Dranse National Nature Reserve
The Delta de la Dranse National Nature Reserve is a nature reserve located in the delta of the Dranse river. The reserve is located to the east of the commune of Thonon-les-Bains in southeastern France. At long by wide, it covers a small area of at an elevation ranging from...
, situated to the east of the commune of Thonon-les-Bains
Thonon-les-Bains
Thonon-les-Bains is a town in the Haute-Savoie department in the Rhône-Alpes region in south-eastern France. It is a sub-prefecture of the department.-History:...
, which although small at an area of 53 hectares (131 acre), offers an incomparable botanic diversity
Biodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...
.
The river is 49.1 kilometres (30.5 mi) long.
Hydrology
The Dranse is a high-volume river, as are all the rivers which originate in the Alpine mountain rangesAlps
The Alps is one of the great mountain range systems of Europe, stretching from Austria and Slovenia in the east through Italy, Switzerland, Liechtenstein and Germany to France in the west....
. Its discharge
Discharge (hydrology)
In hydrology, discharge is the volume rate of water flow, including any suspended solids , dissolved chemical species and/or biologic material , which is transported through a given cross-sectional area...
was observed for a period of 97 years (1906–2003) in Reyvroz
Reyvroz
Reyvroz is a commune in the Haute-Savoie department in the Rhône-Alpes region in south-eastern France.-References:*...
, a locality in the department of Haute-Savoie
Haute-Savoie
Haute-Savoie is a French department in the Rhône-Alpes region of eastern France. It borders both Switzerland and Italy. The capital is Annecy. To the north is Lake Geneva and Switzerland; to the south and southeast are the Mont Blanc and Aravis mountain ranges and the French entrance to the Mont...
situated on the southern bank of Lake Geneva
Lake Geneva
Lake Geneva or Lake Léman is a lake in Switzerland and France. It is one of the largest lakes in Western Europe. 59.53 % of it comes under the jurisdiction of Switzerland , and 40.47 % under France...
at the same elevation
Elevation
The elevation of a geographic location is its height above a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface ....
as its outlet. The drainage basin
Drainage basin
A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...
for the river is in its totality 495 square kilometre, which is not quite three times the surface area
Surface area
Surface area is the measure of how much exposed area a solid object has, expressed in square units. Mathematical description of the surface area is considerably more involved than the definition of arc length of a curve. For polyhedra the surface area is the sum of the areas of its faces...
of the city of Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...
.
The annual average discharge of the river at Reyvroz is 20.1 cubic metre per second.
The Dranse is a typical seasonal river regime
River regime
River regime can describe one of two characteristics of a reach of an alluvial river:* The variability in its discharge throughout the course of a year in response to precipitation, temperature, evapotranspiration, and drainage basin characteristics * A series of characteristic power-law...
, with depends slightly on a small rain
Rain
Rain is liquid precipitation, as opposed to non-liquid kinds of precipitation such as snow, hail and sleet. Rain requires the presence of a thick layer of the atmosphere to have temperatures above the melting point of water near and above the Earth's surface...
component. It exhibits sharply delineated seasonal fluctuations in discharge, which is characteristic of Alpine waterbodies. High flows occur in the springtime and are attributed to snowmelt
Snowmelt
In hydrology, snowmelt is surface runoff produced from melting snow. It can also be used to describe the period or season during which such runoff is produced. Water produced by snowmelt is an important part of the annual water cycle in many parts of the world, in some cases contributing high...
. These accompany average monthly discharges of around 30 cubic metre per second from April to June (the maximum being reached in May). At the end of June, discharge rates sharply drop while the volume moves downstream. From the end of July to the end of February discharge is continuous, fluctuating between 12.7 cubic metre per second, with a low of 12.7 cubic metre in August, and a small "peak" cut in November, linked to the autumn
Autumn
Autumn is one of the four temperate seasons. Autumn marks the transition from summer into winter usually in September or March when the arrival of night becomes noticeably earlier....
al rain. However, these fluctuations are much more pronounced over short periods and depend on the year.
During times of low water, the low water discharge can fall as low as 2.5 cubic metre per second, in the case of a dry quinquennial period, and although low, it is considered normal in the regions of the Alps and Prealps.
In terms of flood
Flood
A flood is an overflow of an expanse of water that submerges land. The EU Floods directive defines a flood as a temporary covering by water of land not normally covered by water...
s which, although uncommon, can be very important, measures with certain "eau du midi". The maximum instantaneous discharge for a two-year (P2) and five-year (P5) flood events
100-year flood
A one-hundred-year flood is calculated to be the level of flood water expected to be equaled or exceeded every 100 years on average. The 100-year flood is more accurately referred to as the 1% annual exceedance probability flood, since it is a flood that has a 1% chance of being equaled or exceeded...
are 180 cubic metre respectively. The ten-year flood event (P10) is 250 cubic metre per second, the twenty-year flood event (P20) 270 cubic metre, and the fifty-year flood (P50) 310 cubic metre.
The highest instantaneous flow recorded by the Reyvroz station was 273 cubic metre per second on the , while the maximum daily value was 229 cubic metre per second on . For comparison, the June 1963 value is comparable to a vicennial flood event, and is thus considered not that exceptional.
The discharge volume of Dranse is augmented by the abundant precipitation
Precipitation (meteorology)
In meteorology, precipitation In meteorology, precipitation In meteorology, precipitation (also known as one of the classes of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation...
in the northern Alps. The runoff curve number for its drainage basin is 1285 millimetres (50.6 in) annually, which elevated, is three times greater than the average for all of France. The specific discharge (Qsp) of the river reaches 40.7 litres (10.8 US gal) per second and square kilometer of the basin.
External links
Le Delta de la Dranse, on the Natura 2000Natura 2000
Natura 2000 is an ecological network of protected areas in the territory of the European Union.-Origins:In May 1992, the governments of the European Communities adopted legislation designed to protect the most seriously threatened habitats and species across Europe. This legislation is called the...
website Banque Hydro - Station V0334010 - La Dranse à Reyvroz (Bioge) (Synthèse) (the "Station en service" is unchecked)