Semine

The Semine , is a French river which runs in the departments of the the Jura and of the Ain. It is an affluent of the Valserine out of Right Bank.

Geography

Semine is born on the territory from the small town from the Spruce, in the department of the the Jura. It moves from the start towards the south, and quickly crosses the limit of the Département of Ain. It will maintain grosso-modo its direction towards the south to its confluence with the Valserine, on the level of the locality of Châtillon-in-Michaille.

Semine crosses the territories of the communes of the Spruce, Belleydoux, Champfromier, Échallon, Saint-Germain-with-Joux and Châtillon-in-Michaille.

Hydrology

Semine is a rather abundant river, like all the rivers resulting from the southern part of the area of the Massif of the Jura. Its flow was observed over one 49 years period (1959-2007), with Châtillon-in-Michaille, locality of the Département of Ain located at the level of its confluence with the Valserine. The catchment area of the river is there of 183 km ² (either the entirety of the basin).

The interannual medium flow or module of the river with Châtillon-in-Michaille is of 9,4 m ³ a second.

Semine present of the seasonal fluctuations of flow which resemble in any point that of Valserine. Its mode is especially nival, with high waters of spring carrying the monthly flow on the level from 13 to 15,1 m ³ a second, of at the end of February with April included (with a top in March), and low waters of summer, of at the end of June at the beginning of September, involving a fall of the monthly medium flow up to 3,78 m ³ in August, which remains very consistent. The river presents moreover a second top smaller in December corresponding to a maximum of the rains of autumnal cold season. The irregularities are however much more marked over moreover short periods.

With the low water level, the VCN3 can fall until 0,7 m ³, in the event of dry quinquennial period, that is to say 700 liters a second, which is normal in these areas. Let us recall that the VCN3 is the past minimal quantity or minimal flow over three days consecutive.

As for the risings, they can be important, definitely more than those of the course higher of Valserine measured than Chézery-Forens little before the confluence of the two rivers, this being related to the flow of Semine definitely higher than that of Valserine. The QIX 2, or calculated flow of biennial rising, and QIX 5 are worth respectively 140 and 180 m ³. The QIX 10 or calculated flow of decennial rising is of 200 m ³ a second, the QIX 20 of 230 m ³ and the QIX 50 of 260 m ³. (see note).

The maximum instantaneous flow recorded with Châtillon-in-Michaille was of 354 m ³ a second on February 15th, 1990, while the value maximum day laborer was of 275 m ³ a second on February 14th of the same year. By comparing the first of these figures on a QIX scale of Semine, it arises that these risings were much stronger than the calculated risings cinquantennales (QIX 50), perhaps centennial or more, and in all the cases, very exceptional.

On the whole, Semine is a very abundant river, supplied with precipitations they also very abundant, in the area of the solid mass of the Jura. The Lame of water past in its catchment area is of 1 625 millimetres annually, which is extremely high, approximately five times superior with the overall average of France. It presents to this level one records in France. The specific Flow of the river (or Qsp) thus reached 51,4 liters a second and per square kilometer of basin, a record him too.

References

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