Nohain

The Nohain is a French Rivière , affluent direct of the the Loire.

Geography

Its course is located entirely in the department Bourguignon of the Nievre (58). Its basin occupies the northern part of the department. It is fed throughout its course by many sources, and enlarges several affluents. It is subdivided in many arms and gives the impression to wander in its own valley. Its length is of 45 km.
It takes its source to 2 km in the North-East of Spirit-on-Nohain.

The south-eastern part of its basin is almost entirely covered with beautiful forests, of which the forest of Courgeonneries, the forest of the Ladies, the forest of Donzy, the national forest of Bellary, etc

Affluents

Talvanne
Acotin

Common crossings

Nohain crosses the following communes: Menestreau, Couloutre, Perroy, Donzy, Suilly-the-Turn, Saint-Quentin-on-Nohain, Saint-Martin-on-Nohain and the Cosne-Course-on-Loire.
It is thrown in the the Loire in this last commune.

Hydrology

Nohain is a fairly abundant river. Its flow was observed for one 37 years period (1970-2007), with Saint-Martin-on-Nohain, locality of the department of the Nievre located little before its confluence with the the Loire. The catchment area of the river is there of 473 km ², i.e. 90% of the totality of this one (which makes 521 of them).

The interannual medium flow or module of the river with Saint-Martin-on-Nohain is of 3,45 m ³ a second.

Nohain present of the seasonal fluctuations of flow little marked, which slices with the majority of the affluents of the Loire, but resembles much the mode of the close Nievre de Champlemy. The high waters are held January at May and push the average monthly flows in a fork going from 3,9 to 5,7 m ³ a second (with an in February maximum). As of at the end of May, the medium flow drops gradually to the low waters of end of be-beginning of autumn which are held August at October included, with a fall of the monthly medium flow up to 1,82 m ³ in September, which remains extremely consistent.

With the low water levels, the VCN3 can fall until 0,63 m ³, which remains very comfortable for a river of this size and slices again with the values recorded for the majority of the affluents of the river, but remains however normal in the Western part of the department of Nievre. One indeed observes a VCN3 of 0,250 m ³ a second for the Nievre de Champlemy for a less wide basin of 60%, and a VCN3 of 0,160 m ³ for the Nievre d' Arzembouy, located more at the east whose size of basin is worth about half of that of Nohain, but whose flow is lower only of one third. As for the risings, they are not too important at least in the context of the basin of the Loire, following the example close Nievre de Champlemy. The QIX 2 and QIX 5 are worth respectively 11 and 16 m ³. The QIX 10 or calculated flow of decennial rising is of 20 m ³ a second, the QIX 20 of 23 m ³ and the QIX 50 of 27 m ³ a second. (see note).

The maximum instantaneous flow recorded with Saint-Martin-on-Nohain was of 23,4 m ³ a second on March 15th, 2001, while the value maximum day laborer was of 23 m ³ a second at the same date. By comparing the instantaneous flow of this rising on a QIX scale of the river, it appears that it was of a vicennial nature, and thus intended to reproduce on average every 20 years.

On the whole, Nohain is a fairly abundant, but rather regular river. The Lame of water past in its catchment area is of 231 millimetres annually, which is certainly lower than the overall average of France, but extremely approaches the average of the basin of the Loire (244 millimetres). The specific Flow (or Qsp) reached the figure of 7,3 liters a second and per square kilometer of basin.

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