Fecht

The Fecht is a French Rivière of Alsace which runs in the Département of Haut-Rhin. It is an affluent of the Ill, therefore a tributary of a tributary of the the Rhine.

Geography

The Grande Fecht takes its source on the Eastern slope of the Massif of the Vosges, with the locality Salzbach , on the territory of the commune of Metzeral. It receives, left bank, the emissary of the Schiessrothried and inflates of two homonymous affluents, the Fecht of Sondernach on its line and, on its left, the Petite Fecht born on the slopes of the Hohneck. It sprinkles Munster and Turckheim. A part is diverted by the Canal of Logelbach, built at the 18th century to feed Colmar, and joined the Lauch. It receives finally the Weiss and is thrown in the Ill in the center of Illhaeusern between Colmar and Sélestat.

Affluents

Fecht de Sondernach
the Small Fecht
Krebsbach
the Weiss
the Strengbach

Hydrology

The flow of Fecht was observed for one 36 years period (1972-2007), with Ostheim, locality of the Département of Haut-Rhin, located not far (6 km) from the confluence with the Ill. The catchment area of the river is there of 447 km ² is more or less 82% of its totality (the basin of its affluent the Strengbach is in particular excluded from it).

The interannual medium flow or module of the river with Ostheim is of 6,79 m ³ a second.

Fecht presents seasonal fluctuations of flow marked well, with high waters of winter carrying the average monthly flow on a level located between 8,55 and 11,9 m ³ a second, from December to April included (maximum in February and March). As of April, the medium flow drops gradually throughout spring to the low waters of summer which take place from July to September, involving a fall of the monthly medium flow going until 1,98 m ³ in August, which remains very comfortable, it is true. But the fluctuations of flow can be much more important over short periods and according to the years.

The VCN3 can thus fall until 0,430 m ³, in the event of dry period quinquennial, that is to say 430 liters a second, which is however not yet very severe (see note).

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 71 and 98 m ³. The QIX 10 or calculated flow of decennial rising is worth 120 m ³ a second, while the QIX 20 is assembled to 130 m ³. Finally the QIX 50 is worth 160 m ³ a second. (see note). The recorded maximum instantaneous flow was of 140 m ³ a second on February 15th, 1990, while the value maximum day laborer was of 124 m ³ a second the same day. By comparing the first of these figures with the values of the various QIX of the river, it appears that this rising was a little more than of a vicennial nature and thus unexceptional. One can consider that it is intended to on average repeat the every 25-30 years.

Like all the rivers resulting from the solid mass of the Vosges and thus profiting from strong precipitations, Fecht is an abundant river. The Lame of water past in its basin is of 481 millimetres annually, which is high, very definitely higher than the overall average of France all confused basins, but also than that of the whole of the catchment area of the Ill (398 millimetres in Strasbourg). The specific Débit (or Qsp) is assembled consequently at 15,2 liters a second and per square kilometer of basin.

Random links: