Small fireclay cup (river)

The Têt (in Catalan the Small fireclay cup ) is a coastal Fleuve French of the the Eastern Pyrenees of 120 km length. The valley of the Small fireclay cup is classified country of art and history.

Geography

The Small fireclay cup takes its source with the foot of the Pic Carlit, crosses of West Is the department the Eastern Pyrenees, initially the Conflent, then the Roussillon, and is thrown in the Mediterranean.

Its course is barred close to its source to the Bouillouses (hydro-electric Barrage) and to Vinça (storage dam).

Principal affluents

the Riberole
the Carança
the Mantet
the Rotja (Fuilla)
the Cady (Vernet-the-Baths)
the Castellane (collar of Jau)
the Lentilla (Baillestavy)
the Balls
the Caillan (Nohèdes)
the Low (Perpignan)

Hydrology

Born in the the Pyrenees, its spring mode depends on snowing up and of the cast iron of the Neige S. If its flow is often low, the Small fireclay cup can know Crue S spectacular and its flow to reach a record of 3600 m ³ /s, as at the time of large the Flood ( aiguat ) of October 1940.

Its flow was observed over one 32 years period (1976-2007), with Rodes, small town of the the Eastern Pyrenees, located at the foot of the stopping of Vinça and thus rather distant from its mouth in the sea. The catchment area of the river is there of 974 km ², i.e. 63 % of its totality (which is worth 1 550 km ²). The following flows are thus not the natural flows, because strongly influenced by the startup of the stopping in 1976.

The interannual medium flow or module of the river with Rodes is of 9,97 m ³ a second.

The Small fireclay cup presents typical seasonal fluctuations of a mode to dominant nival undeniable. One indeed distinguishes two periods there from rising. The high waters of end of autumn carry the average monthly flow at 9,9 m ³ a second, in December and are followed of a light fall of flow up to 7,6 m ³ a second in February. A second rise of the mode follows then leading to a second top - by far most important - in May (21,5 m ³). It is due to the snow melt. By after, as of June, starts fall fast followed of low waters of summer which leads the medium flow to its low water level of August with a monthly average of 5,77 m ³ a second, which remains rather high, it is true. On the whole, the seasonal oscillations appear important thus very little, but the fluctuations are much more marked over moreover short periods.

With the low water level, the VCN3 can fall until 1,3 m ³, in the event of dry period quinquennial, which is far from being severe if one compares it with the average of the rivers of France. Let us recall that the VCN3 is the past minimal quantity or minimal flow over three days consecutive. Not to lose sight of the fact that the minimum flow is supported by the destocking of the stopping of Vinça.

As for the risings, they can be very important, though usually chopped by the construction of the stopping. The QIX 2 or calculated flow of biennial rising and QIX 5 (calculated flow of quinquennial rising) are worth respectively 140 and 240 m ³. The QIX 10 or calculated flow of decennial rising is of 300 m ³ a second and the QIX 20 of 360 m ³. As for the QIX 50 or computed value of the flow of raw cinquantennale, it is worth 430 m ³. (see note). That means that, for example, every two years one must expect a rising of about 140 cubic meters, and that every five years, a rising of 240 cubic meters must statistically occur.

To have an idea of the importance of these flows of rising, one can compare them with those of Loing important affluent of the Seine, upstream of Paris, whose risings are famous and were a long time dreaded, but river somewhat currently regularized. The QIX 5 of Loing is worth 150 m ³ (against 240 for the Small fireclay cup) and its QIX 20 is assembled to 220 m ³ (either much less than the 360 of the Small fireclay cup). As it is noted, the risings of the Small fireclay cup are definitely higher than those of Loing upstream of Paris, and this although its basin is four times less wide, and its flow twice less abundant.

The maximum instantaneous flow recorded during the period of 32 years observation was of 533 m ³ a second on May 19th, 1977, while the value maximum day laborer was of 345 m ³ a second the same day. By comparing the first of these values with the scale of the QIX of the river, it appears that this rising was much more important than the calculated rising cinquantennale (QIX 50), and undoubtedly very exceptional.

On the whole, the Small fireclay cup is a small fairly abundant river, fed above all by precipitations, especially snow-covered, of the Eastern tops of the Pyrenees. The Lame of water past in its catchment area is of 323 millimetres annually, which is moderate, equivalent to the overall average of France all confused basins. The specific Flow of the river (or Qsp) reached the figure of 10,2 liters a second and per square kilometer of basin.

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