Moselotte

Moselotte
The Moselotte flowing through Cornimont
Mouth	Moselle
Basin countries	France
Length	47 km
Avg. discharge	13.7 m³/s
Basin area	356 km²

The gorge at Croséry à Thiéfosse

The Moselotte is a river in Lorraine, in the French department of Vosges. It is a direct right tributary of the Moselle, and thus a sub-tributary of the Rhine.

Geography

The Moselotte rises in the massif des Vosges at the fontaine de la Duchesse, near the summit of Hohneck. It flows into the Moselle at Remiremont. Its length is 47 km, while its watershed is 356 km².

Communes traversed by the Moselotte

The Moselotte flows through, from upstream to downstream, the communes of La Bresse, Cornimont, Saulxures, Thiéfosse, Vagney, Saint-Amé, Le Syndicat, Dommartin-lès-Remiremont and Saint-Étienne-lès-Remiremont opposite the town of Remiremont.

Main tributaries

The Moselotte is fed by the following tributaries:

Vologne Blanchemer (flows through lac de Blanchemer) Régit Machey (from Corbeaux) Goutte de la Vierge Goutte du Pont d'Air Goutte du Pré Guéry Goutte de Séchemer Goutte du Lac des Corbeaux Goutte des Betches Goutte des Ecorces Chajoux (from lac de Lispach) Grande Goutte

Goutte de la Louvière Goutte du Brabant Goutte du Reucy Goutte du Raindé Goutte du Couchetat Goutte de Parfongoutte Goutte du Droit Xoulces Ventron Géhant Morbieux Rupt de Bâmont Amias

Grettery Envers des Graviers Envers de Thiéfosse Droit de Thiéfosse Rupt Solem Demixard Pennecières Bouchot Lémont Cleurie.

Lakes

The Moselotte watershed includes numerous natural lakes which are often enhanced by a small barrage, including lac de Blanchemer, lac de Lispach and lac des Corbeaux.

The presence of a high barrage at the foot of Kastelberg since 1983 has resulted in the appearance of the lac de la Lande. It collects water from several sources via conduits, and supplies the La Bresse commune with its energy.

At the entry downstream of Saulxures, a lake of 9.6 hectares was set up in 1998 under the name lac de la Moselotte which hosts a leisure center.

Hydrology - at Vagney station

Like the majority of Vosges rivers, the Moselotte is very substantial. Its flow rate has been oberved during a period of 40 years Vagney at a place called Zainvilliers, which is situated upstream of the Moselotte's confluence with the Moselle^[1]. The river's watershed at this point is 187 km² or 53% of its entire watershed, corresponding to the upper half of its course.

The average interannual flow rate, or discharge at Vagney is 8.54 m³/s.

The Moselotte exhibits quite marked seasonal fluctuations, with a winter-spring period of high water whose monthly average flow rate is between 10.8 and 13.2 m³/s from November to April inclusive, with a maximum in December. From the beginning of May, the flow rate falls off rapidly, reaching 3.06 m³/s in August, which is not very severe for a body of water of this size. However year by year fluctuation can be more significant, as can those in the short term.

Average monthly flow rate of the Moselotte (m³/s) measured at Vagney hydrological station
Data taken over a 40 year period

At low water, the 3-year low instantaneous flow rate can drop to 0.37 m³/s in the case of a dry five-year period, or about 370 litres per second, which is quite severe, but typical of rivers in the Moselle basin.

Floods can also be significant particularly bearing in mind the smallness of the watershed (only 187 km²). The maximum instantaneous flow rates over a 2-year and 5-year period (MIFR2 and MIFR5) measure 97 and 110 m³/s respectively. The MIFR10 is 120 m³/s, the MIFR20 is 130 m³/s, while the MIFR50 rises to 150 m³/s/

The maximum instantaneous flow rate recorded at Vagney was 121 m³/s on 15 February 1990, while the maximum daily average flow rate was 108 m³/s on the same day. Comparing these values to the MIFR measurements for the river suggests that the flood on that day was approximately a 10-year event and thus likely to recur frequently.

Overall the Moselotte is an extremely abundant river in its upper course. The runoff curve number in this 53% of its watershed is 1,445 mm annually, which is extremely high for the northern part of France, and more than four times higher than the French national average. It is also three times higher than the average over the French basin of the Moselle. The specific flow rate attaches to these facts the portentous figure of 45.7 litres per second per square kilometre of watershed.

Hydrology - at the confluence with the Moselle

The interannual flow rate/discharge of the Moselotte at its confluence with the Moselle is 13.7 m³/s, for a watershed of 356 km²^[2]. The runoff curve number in its watershed is 1,214 mm, which is very high indeed, not merely much higher than the average for France (by more than a factor of three) with all basins included, but also much higher than the average for the French Moselle basin. In fact, the runoff curve number at Hauconcourt, located slightly downstream of the town of Metz, near where it leaves French territory, rises to 445 mm^[3]. The specific flow rate of the Moselotte rises to 38.5 litres per second per square kilometre of watershed. This, along with the Breuchin (a tributary of the Lanterne and sub-tributary of the Saône which flows elsewhere in the same region) constitutes a record for the north third of France.

The Moselotte is clearly more abundant than the Moselle at their confluence (13.7 m³/s against 9.3 m³/s ^[4]).

Water quality

While in 2005, the water quality of the Moselotte was classified as category 1B, or "bonne" (good), the situation deteriorated somewhat in 2006, when the Rhine-Meuse water agency concluded that the river water analysed at the level of Autrive was now only "passable", or category 2. ^[5]. The reason was a highly depressed rate of oxygen saturation (also classed as "passable"), which had gone from 76% in 2005 to 69% in 2006. It should be noted that the chemical oxygen demand, at 6.5 mg/l in 2006, was still classified "bonne". The ammonium ion level was measured at 0.09 mg/l, which was classed as "excellent".

The Bas de La Bresse

Saulxures-sur-Moselotte: The lac de la Moselotte

Abbey church of Saint-Pierre de Remiremont

Economy

Highly populated by trout, the river has given rise to a significant breakthrough in fish farming, namely the invention of artificial reproduction by Joseph Remy and Antoine Géhin in the 19th century. The Moselotte basin also has the highest density in the world in small hydroelectric barrages, which serve the watermills, sawmills, spinning and weaving houses along the river and its tributaries.

The photograph opposite, taken upstream of La Bresse, shows a diversion powering a turbine. The main point has been equipped with a fish ladder.

A railway line once ran along the Moselotte valley between Remiremont and Cornimont. Today it has been transformed into a voie verte (green route) and replaced with bus service provided by TER Lorraine (line 9), extended to La Bresse.

See also

• List of rivers of France
• Moselle

External links

• (French) SANDRE website (code for the Moselotte: A41-0200)
• (French) Description on the Pays de Remiremont website
• (French) Characteristic flow rates of the MoselottePDF

References

1. ^ Banque Hydro - Station A4140202 - La Moselotte à Vagney (option Synthèse) (don't tick "Station en service")
2. ^ Characteristic flow rates of the MoselottePDF
3. ^ Banque Hydro - Station A7930610 - La Moselle à Hauconcourt (Do not tick the box for "Station en service")
4. ^ Characteristic flow rates of the Moselle upstreamPDF
5. ^ (French)SIERM - Système d'Information sur l'Eau Rhin-Meuse: Qualité de l'eau superficielle (cours d'eau)

Coordinates: 48°01′N 6°37′E / 48.017°N 6.617°E / 48.017; 6.617