The Treulon is small a French Rivière which runs in the departments of the Mayenne (53) and of the the Sarthe (72). It is an important affluent of the Erve, therefore a tributary of a tributary of the the Loire by Huisne, the the Sarthe and the Maine.

Geography

Treulon is born in the forest from Large the Charnie on the territory from the commune of Torcé-Fish pond-in-Charnie, in the department of the Mayenne. As of its birth, it adopts the direction of the south, which it will maintain until the end of its course. It separates the the Sarthe from Mayenne on a course of 1 km, on the level of Blandouet, enters the department of the Sarthe, is used to him as limit on a course of 5 km, passes in Mayenne, and enters the Sarthe again. It is thrown in the Erve with Auvers-le-Hamon.

Common crossings

Treulon crosses successively the following communes:

• Department of the Mayenne: Torcé-Fish pond-in-Charnie and Blandouet.
• Department of the the Sarthe: Saint-Denis-with Orques and Transfer-in-Champagne
• Department of the Mayenne: Hampers, Thimble-in-Champagne and Thorn-bush-the-Seguin
• Department of the the Sarthe: Auvers-le-Hamon.

Hydrology

The flow of Treulon was observed for one 14 years period (1992-2008), with Auvers-le-Hamon, locality of the department of the Sarthe, located at the level of the confluence with the Erve (ref.: ). The catchment area of the river is of 143 km ².

The interannual medium flow or module of the river with Auvers-le-Hamon is of 0,995 m ³ a second.

Treulon presents seasonal fluctuations of flow important. The high waters take place in winter and are accompanied by average monthly flows going from 2,03 to 2,75 m ³ a second, from December to February-March included (maximum in January). As of March, the flow decreases gradually until the period of the low waters of summer, which are held June at September included, and involve a fall of the monthly medium flow going until 0,088 m ³ in August (88 liters a second), which can be regarded as severe.

However, with the low water level, the VCN3 can fall until 0,005 m ³, in the event of dry period quinquennial, that is to say 5 liters a second, which becomes very severe, the river being then reduced to some nets water. The VCN3 is the past minimal quantity or minimal flow over three days consecutive.

In addition the risings can be rather important. The QIX 2 and QIX 5 or calculated flows of biennial and quinquennial rising are worth respectively 23 and 33 m ³. The QIX 10 or calculated flow of decennial rising is worth 40 m ³ a second, while the QIX 20 is assembled to 46 m ³. Finally the QIX 50 was not calculated fault one duration of sufficient observation to determine it validly (see note). The recorded maximum instantaneous flow was of 34,1 m ³ a second on January 13rd, 2004, while the value maximum day laborer was of 23,1 m ³ a second on December 28th, 1999. By comparing the first of these figures with the values of the various QIX of the river, it appears that this rising even was of a decennial nature and thus completely banal and by no means exceptional. One can consider that it is intended to on average repeat the every 5-10 years.

The Lame of water past in the basin of Treulon is of 220 millimetres annually, which is not weak whole for a river of plain of the basin of the Loire. It is of course definitely lower than the overall average of France, and lower also - but of little than the catchment whole of the area of the Loire (244 millimetres), but higher than the whole of the basin of the the Sarthe (201 mm). The specific Débit (or Qsp) is assembled consequently at 7,0 liters a second and per square kilometer of basin.