Mayenne (river)

The Mayenne is a river West of the France being located mainly in the area of the Pays of the Loire. It takes its source in the hills of the Perche, approximately 15 kilometers in the west of Alençon, in the Orne (61) on the territory of the commune of Lalacelle, and joined the the Sarthe, with which it forms the Maine, in the north of Angers, in Maine-et-Loire (49).

Geography

After its birth with the foot of the Mount of the Heads to 293 meters of altitude, Mayenne runs of Is in West until Seven-Forging mills, for then taking a North-South direction. It enters in Maine-et-Loire close to Jaille-Yvon, and receives the tributary fort of the Oudon, with the lower part of the Lion-in Angers. Beyond Cantenay-Spinach, it joins the the Sarthe, grown bigger Loir, and forms the island Saint-Aubin upstream of Angers. The meeting of the two rivers gives rise to the Maine which passes to Angers and Bouchemaine before throwing in the the Loire with the Point.

Of Evière with Pierre Bécherelle, the river belonged to the field of the chapter Saint-Laud which charged the fees, leased the vats and made each year draw the Quintaine under the castle.

Hydrography - Affluents

Its principal affluents and tributaries of a tributary are (of upstream downstream):

Navigation

Mayenne was navigable. Projects, are launched in 1783 to make navigable the Vilaine of Vitré until Redon, to join the Vilaine to the Rance, and Mayenne by two navigable channels. (see: Channel of It)

Important work was made of 1853 with 1868. In 1863, work of deepening of the bed of Mayenne was undertaken close to the locality ford of Saint-Léonard , delivering a considerable mass of currencies… (which) was deposited for study with the Cabinet of the medals in 1997.

It is navigable of Laval to the Loire, and was channeled of Laval with Mayenne. At the 19th century, it carried boats whose load reached sometimes 130 tons, transporting construction materials especially (stone S and Bois), Anthracite coming from the mines of the Door frame, of the grains, of the Fruit S and the Légume S. Of the Steamers furrowed its course between Castle-Gontier and Angers.

Departments and main cities crossed

Hydrology

In spite of rather abundant precipitations, the mode (rain oceanic) of Mayenne is irregular because of the impermeability of the sandstone, Granit S and Schiste S which forms its basin. Thus, for a medium flow of 39 m ³ /s before the junction with the Oudon, the low water level S of the river can be very low (4 m ³ /s with Laval), the constant Crue S (200 m ³ /s in this same city and more than 800 m ³ /s in Chambellay).

The flow of Mayenne was observed during one 43 years period (1965-2007), with Chambellay, locality of the Département of Maine-et-Loire, located unfortunately extremely upstream of the junction with the the Sarthe, just upstream of the outlet of the Oudon. At this place the catchment area of the river is of 4  160 km ² on a total of 5  820, is less of the three quarters of entirety of the basin (71,5%), and without the flows due to the Oudon, its principal affluent. However the figures obtained are perfectly significant.

The interannual medium flow or module of the river with Chambellay is of 39,0 m ³ a second what corresponds to more than 50 m ³ for the totality of the basin.

Mayenne present of the seasonal fluctuations of flow rather important, more marked than in the basins close to the Sarthe, Huisne and the Dormouse, alternating high waters of winter, with the average monthly flow from 62 to 90 m ³ a second December at March included (maximum in January), with low waters of summer from July to September, involving a fall of the monthly medium flow up to the level of 6,93 m ³ in August.

The VCN3 can fall until 1,1 m ³, in the event of dry period quinquennial what is very little and must be regarded as severe for a river of this importance (see note).

In addition the risings can be extremely important, worsened by the impermeability of the grounds. Indeed, the maximum instantaneous flow recorded at this place was of 824 m ³ a second on November 17th, 1974, while the median value maximum day laborer was of 798 m ³ a second on October 29th, 1966. The QIX 2 and QIX 5, or flows calculated for a biennial and quinquennial rising, are worth respectively 350 and 510 m ³ a second. The QIX 10 or calculated flow of decennial rising is of 620 m ³ a second and the QIX 20 of 720 m ³. As for the QIX 50, it is assembled to step less than 850 m ³ a second (see note). While not forgetting that these figures relate only to 72% of the catchment area and escamottent the important flows of the Oudon (medium flow of 9,04 m ³ a second), one must note that Mayenne is far from being a quiet river. The probabilities of important rising are at least equivalent to those of the Yonne, and quite higher than those of the Marne in Paris.

The Lame of water past in the basin of Mayenne is of 297 millimetres annually, which corresponds more or less to the French average all confused basins. The water blade is definitely higher than the average of the basins of the Sarthe and the Dormouse, but also higher than that of the whole of the catchment area of the Loire (260 millimetres). The specific Débit (or Qsp) is assembled at 9,4 liters a second and per square kilometer of basin.

Islands

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