Clain

The Clain is a river French of average importance, which takes its source close to Hiesse in Charente and crosses the department of the Vienna before throwing in the of the same river name, close to Châtellerault, with Cenon-sur-Vienne.

Geography

Clain is thus born in Charente, but the essence of its course is located in Vienna. It crosses the towns of Vivonne and Poitiers before joining Vienna close to Châtellerault.

Calcareous river of country, it strongly notches the plate, forming a valley steepsided out of U (or trough) fifty depth meters. Its méandreux course forms banks escarpées on the convex side of the course in with respect to an average inclined bank on the concave side.

Affluents

the Préhobe (with Pressac, 6,8 km length) ;
the Payroux (with Payroux, 18 km length, Maury are an affluent) ;
the Divine (river which passes to Couhé and of which the course with the characteristic to disappear under ground) ;
the Bouleure (with Voulon, approx. 40 km, river temporary most of the year, but remarkable) ;
the Beautiful with Vivonne ;
the Vonne with Vivonne ;
the Clouère ;
the Miosson with Saint-Beno4it cheese ;
the Boivre with Poitiers ;
the Auxances and its affluent the Vandelogne ;
the Palu .

Hydrology

Clain is not a river prone to catastrophic floods. But the local rains can cause important overflows in its steepsided valley. Most important to December 1982 goes back, when it had cut circulation on the boulevards of Poitiers and had submerged all the bridges (except the bridge of the expressway known as Pénétrante ).

centennial Rising measured with 5m60
February 2007 approximately 3m65 on March 3rd, 2007

Flows

The flow of Clain was observed over one 32 years period (1965-1996), with Dissay, locality of the department of the Vienna, located at the south of Châtellerault, with little distance from the confluence with Vienna. At this place the catchment area of the river is of 2 886 km ² on a total of 2 965, is 97% of totality.

The interannual medium flow or module of the river with Dissay is of 20,4 m ³ a second.

Clain present of the seasonal fluctuations of medium flow, with high waters of winter carrying the average monthly flow between 27 and 43 m ³ a second, from December to April included (maximum in January and especially February), and of low waters of summer from July to October, with a fall of the monthly medium flow up to the level of 6,09 m ³ in August.

VCN3 (past minimal quantity or minimal flow over three days consecutive) can fall until 1,6 m ³, in the event of dry quinquennial period.

In addition the risings can take a certain importance without reaching catastrophic levels. The recorded maximum instantaneous flow was of 413 m ³ a second on January 24th, 1995, while the value maximum day laborer was of 382 m ³ a second the same day. QIX 10, or calculated flow of decennial rising, is of 250 m ³ a second. As for QIX 50, it is of 360 m ³, that is to say 12% of that of the Vienna to Nouâtre).

As comparison, the QIX 10 of the Marne at the entry of Paris is worth 510 m ³ a second, while its QIX 50 is of 650 m ³. One can thus notice that the QIX 10 like the QIX 50 of Clain, average river, is of a little more half of those of the Marne, whereas the catchment area of the latter is four times wider.

The Lame of water past in the basin of Clain is of 223 millimetres annually, which is relatively weak, definitely lower than the overall average of France, but also strong lower than that of the whole of the catchment area of the Vienna (319 millimetres). The specific Débit (or Qsp) is assembled at 7,1 liters a second and per square kilometer of basin.

References

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