Arnon

Geography

It takes its source in the extreme North-East of the department of the Creuse, close to Saint-Marien at an altitude of 438 Mr. It bathes Culan, Lignières, Chârost and is thrown in the Cher, below Vierzon, after a course of 150 kilometers.

Principal affluents

the Merry
the Sinaise
the Théols

Hydrology

Arnon is a river poorly abundant, like the majority of the rivers of plain of the catchment area of the Loire. Its flow was observed over one 35 years period (1960-2002), with Méreau, locality of the Département of Expensive the located at very little distance to the south of Vierzon, i.e. little before its confluence with the Cher. The catchment area of the river is there of 2 164 km ², are it quasi totality of this last.

The interannual medium flow or module of the river with Méreau is of 13,5 m ³ a second.

Arnon present of the seasonal fluctuations of flow marked enough, with high waters of winter-spring carrying the average flow monthly on a level located between 17,7 and 33,3 m ³ a second, from December to March included (with an in February maximum), and low waters of be-autumn, from July to October included, with a fall of the monthly medium flow up to 4,98 m ³ in August, which remains very appreciable.

With the low water level, the VCN3 can fall until 1,5 m ³, in the event of dry quinquennial period, that is to say 1 500 liters a second, which is not too severe. The VCN3 is the past minimal quantity or minimal flow over three days consecutive.

As for the risings, they can be rather important, characteristic shared by the majority of the affluents of the Loire, but without common measurement with the risings of the affluents of the Loire located at the west of the basin (Creuse, Gartempe, Mayenne, Sèvre Nantes or Oudon and Anglin).

Thus the QIX 2 and QIX 5 or calculated flows of biennial and quinquennial rising are worth respectively 100 and 160 m ³ a second. The QIX 10 or calculated flow of decennial rising is of 190 m ³ a second, the QIX 20 of 230 m ³, while the QIX 50 was not calculated (see note).

It can be interesting to compare the QIX 2 and Nantes QIX 10 of Arnon to those of Anglin and Sèvre to rather comparable dimensions of basin. Whereas the QIX 2 of Arnon is assembled to 100 m ³ a second, that of Anglin is worth of them 210 and that of Sèvre Nantes is of 280 m ³ (for a medium flow higher of 80% than that of Arnon, it is true). As for the QIX 10, that of Arnon being of 190 m ³ a second, it goes up to 400 m ³ for Anglin and to 570 for Separates. One concludes from it that the risings of Arnon are about twice less important than those of these two rivers of the west of the basin of the Loire.

The recorded maximum instantaneous flow with Méreau during the period of observation, was of 242 m ³ a second on May 1st, 1977, while the value maximum day laborer was of 223 m ³ a second on May 29th of the same year. By comparing the first of these values on a QIX scale of the river, one notes that this rising was only of a vicennial nature, and thus intended to rather frequently reproduce.

Arnon is not a very abundant river. The Lame of water past in its catchment area is of 200 millimetres annually, which is definitely lower than the overall average of France all confused basins, and also to the average of the basins of the Cher (223 millimetres with Tours), and of the the Loire (244 millimetres). The specific Débit of the river (or Qsp) posts of this fact a rather weak figure: 6,3 liters a second and per square kilometer of basin.

Random links: