Envigne

The Envigne is a River French which runs in the department of the Vienna in area Poitou-Charentes. It is an affluent of the Vienna out of left bank, therefore a tributary of a tributary of the the Loire.

Geography

Envigne is born on the territory from the commune of Chouppes, with three kilometers in the north of Mirebeau. Its head office goes from west in east. It is thrown in the Vienna, with Châtellerault (left bank). It has a length of approximately 32 km.

Common crossings

Envigne crosses the following communes: Chouppes, Coussay, Doussay, Cernay, Lencloître, Saint-Genest-with Ambière, Marigny-Brizay, Ouzilly, Dovecotes, Scorbé-Clairvaux, Naintré, Thuré and Châtellerault, all located in the department of the Vienna.

Hydrology

Envigne is a river very little provided. Its flow was observed for one 40 years period (1968-2007), with Thuré, locality of the department of the Vienna, located very close to the confluence with Vienna (ref.: ). The catchment area of the river is of 242 km ², i.e. its quasi totality.

The interannual medium flow or module of the river with Thuré is of 0,731 m ³ a second.

Envigne presents seasonal fluctuations of flow important. The high waters take place in winter and are accompanied by average monthly flows of 1,29 and 1,61 m ³ a second, from January to March included (maximum in January). As of April, the flow falls seriously then the fall continues gently, to the low waters of be-autumn which occur July at October included, with a fall of the monthly medium flow going until 0,19 m ³ in August (190 liters a second), which is very acceptable and by no means severe.

Concerning the low water levels, the VCN3 was not calculated (see note). On the other hand the QMNA was it and is assembled to 0,013 m ³ a second, in the event of dry period quinquennial, that is to say 13 liters a second, which is severe (see note).

In addition the risings important, at least are not hardly compared with the average of the affluents of the Loire and more particularly of Vienna, and this being given very low rainfall in the basin and the nature of the grounds of this last. The QIX 2 and QIX 5 or calculated flows of biennial and quinquennial rising are worth respectively 7 and 11 m ³. The QIX 10 or calculated flow of decennial rising is worth 14 m ³ a second, while the QIX 20 is assembled to 16 m ³. As for the QIX 50, it was not published. (see note). The recorded maximum instantaneous flow with Thuré was of 18,4 m ³ a second on December 29th, 1999, while the value maximum day laborer was of 11,5 m ³ a second on May 27th, 1971. By comparing the first of these figures with the values of the various QIX of the river, it appears that this rising was largely higher than the vicennial rising defined by the QIX 20 and thus enough exceptional. The Lame of water past in the basin of Envigne is of 95 millimetres annually, which is very poor, more than three times lower than the overall average of France, and twice and half less than the whole of the catchment area of the Loire (244 millimetres). The specific Débit (or Qsp) is assembled consequently at small 3,0 liters a second and per square kilometer of basin.

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