Aumance

The Aumance is a French river, tributary of Right Bank of the Cher, whose courses, like the catchment area, are entirely in the Département Allier.

Its recorded medium flow with Hérisson is of 6,51 m ³ a second, but is prone to strong irregularities. The river can present frightening risings, up to 300 m ³ a second.

Aumance has for principal affluent the Oeil which joined it with Cosne-with Allier.

Affluents

the Oeil
the Bandaged

Hydrology

The annual medium flow of Aumance, calculated over 38 years with Hedgehog (of 1970 to 2007), is of 6,51 m ³ a second for a surface of basin of 928 km ², that is to say almost the totality of this last.

The river present of important seasonal fluctuations of flow, with risings of winter-spring carrying the average monthly flow on a level located between 6,55 and 12 m ³ from December at May included, and of low waters of be-autumn, June to October, characterized by a fall of the monthly medium flow up to 1,18 m ³ in September. But these monthly averages hide oscillations much more important over short periods.

In period of low water level, the VCN3 can fall up to 0,07 m ³, in the event of dry quinquennial period, that is to say 70 liters a second. Let us recall that the VCN3 is the past minimal quantity or minimal flow over three days consecutive.

The risings of Aumance can be enormous for a small river of only 986 km ² of basin. The QIX 2 and QIX 5 or calculated flows of biennial and quinquennial rising are worth respectively 89 and 130 m ³ a second. The QIX 10 or calculated flow of decennial rising is of 150 m ³ a second, the QIX 20 of 180 m ³, while the QIX 50 is assembled to 210 m ³ a second (see note). The Lame of water past in the basin is of 222 millimetres annually, which can be regarded as means without more, because definitely lower than the French average all confused basins, but is higher than the figures recorded on many river of the basin of Expensive or Indre neighbor. The specific Débit (Qsp) is assembled at 7,0 liters a second and per square kilometer of basin.

Always in Hérisson, the recorded maximum instantaneous flow was of 288 m ³ a second on March 2nd, 2007, while the value maximum day laborer was of 216 m ³ a second on May 27th, 1977.

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