Fensch

The Fensch or Fentsch is a river in the Moselle department of the Grand Est region of France. It is a left tributary of the Moselle, and thus a sub-tributary of the Rhine.

Geography
The Fensch is 15.2 km long. It rises in Fontoy in the west of the Moselle department. It then crosses Knutange, Nilvange, Hayange, Serémange-Erzange and Florange  before discharging from the left into the Moselle between Metz and Thionville on the border of the commune of Illange. It generally flows from west to east.

Originally, as shown by the Cassini map, the waters of the lower part of the Fensch combined with the waters of the Veymerange and fed the moat around the town of Thionville before joining the Moselle. After the removal of the fortifications, the Fensch was diverted to its current course to supply water to the new ironworks installed a little south of this locality. The springs of Morlange (now part of Fameck) and of Ranguevaux were captured in 1886 and carried by gravity to Thionville by a 10 km long conduit.

Names

 * Feuschen (1403), Fensth (1544), Flensch (1606), Fenche (1779), Feusche
 * In German: Fentsch

Communes and cantons crossed
The Fensch crosses seven communes and four cantons in the department of Moselle. From upstream to downstream these are Fontoy (source), Knutange, Nilvange, Hayange, Serémange-Erzange, Florange and Illange (mouth). In terms of cantons, the Fensch originates in the canton of Algrange, crosses the canton of Hayange and canton of Fameck, and has its mouth in the canton of Yutz.

Tributaries
The river has four tributaries:
 * The petite Fensch
 * The Krisbach or Krebsbach 9.6 km long in the three communes of Ranguevaux, Fameck and Florange.
 * The Algrange and Marspich streams
 * The canalized Moselle

Hydrology
The Fensch is fed by a fairly high rainfall. It also receives significant amounts of mine water from mines in the region, which helps to increase the flow. The flow was observed for a period of 35 years (1968–2002) in Florange, a locality in the Moselle department at its confluence with the Moselle. The total area of the river's watershed is 82.6 km2. The average flow of the river at Florange is 2.06 m3/s.

The Fensch has very moderate seasonal fluctuations of flow, which is rarely the case in northern Lorraine. High water events occur in winter and are characterized by average monthly flows in the range of 2.37 to 3.25 m3/s from December to April inclusive (with a maximum in February). Beginning in April, the flow gradually decreases to the low summer-fall waters that occur from July to October. The average monthly flow decreases to a consistent flow of about 1.30 m3/s in September. The fluctuations are more pronounced over short periods or between years.



At low water level, the 3 consecutive-day minimum flow can drop to 0.54 m3/s during a five-year dry period, which is far from severe. Floods are moderately important, given the small size of its watershed. They are proportionally more or less half as large as those of its neighbor, the Orne. The 2-year and 5-year peak instantaneous flows are 7.6 m3/s and 9.5 m3/s. The 10-year peak flow is 11 m3/s, the 20-year peak flow is 12 m3/s and the 50-year peak flow is 14 m3/s. The highest instantaneous flow recorded at Florange was 12.3 m3/s on 12 April 1983, with an average flow of 11.5 m3/s that day. This flood was of a two-year order, and therefore not at all exceptional.

Overall, the Fensch is a very abundant river, more than most rivers of the Moselle basin, particularly those of the Moselle department. Annual rainfall in its basin is 789 mm, which is more than twice that of France as a whole and well above the average of the French part of the Moselle basin, which is 445 mm per year. The river's flow reaches 24.9 L/s per 1 km2 of the basin.



Industry
The Fensch Valley is known for its iron and steel industry. Part of the course of the river is even covered where it crosses the town of Hayange and by facilities of the ArcelorMittal ironworks of Florange. The foundation stone for the Sollac mill was laid on 23 December 1949 in the small village of Serémange on the banks of Fensch river. U.S. Ambassador David K. E. Bruce said at the groundbreaking ceremony, which was attended by the French Foreign Minister Robert Schuman and Minister of Industry Robert Lacoste, that he hoped the French iron-steel industry would soon be the first in Europe".

Culture
The region inspired Bernard Lavilliers's Fensch Vallée, the title song of his fourth album, Les Barbares (1976).