Panettone

Etymology

The etymology of the name comes from the Germanic “ sach ” (point, knife) and “ husband ” (water), “ water (river) with the stones like knives ”.

Old orthographies:

Sesmara (2nd century)
Sesomiris (644)
Sesmarus (950)
Sesmoys (1104)
Seeder (1244).

Affluents

the Vierre (confluent with Jamoigne)
the Rulles or Rule (confluent with Tintigny)
the Midsummer's Day

Hydrology

In Bohan in Belgium

The medium flow of the river measured with Bohan, at the Franco-Belgian border, between 1992 and 2001 is of 32,7 m ³ a second. During the same period, one recorded:

a maximum average annual flow of 40,0 m ³ in 2001.
a minimal average annual flow of 16,3 m ³ in 1996.

Always in Bohan, of 1992 to 2001, over one 10 years period, one calculated:

an average DCC of 146,8 m ³ a second, with a maximum of 246,7 for the year 1993 and one minimum of 80,9 per 1996.
an average DCE of 2,7 m ³ a second, with a minimal DCE of 1,5 in 1996.

Note:

the flow characteristic of raw (DCC) is the daily output exceeded 10 days per annum, and thus unfulfilled the 355 remaining days. The DCC is a value representative of high waters in hydrology. But it is not the extreme value.

the flow characteristic of low water level (DCE) is the daily output exceeded 355 days per annum, i.e. the flow unfulfilled 10 days per annum. This DCE is statistics very much used in hydrology to appreciate the importance of the low water levels of a river.

Source: Ministry for the Walloon region .

According to the measurements thus taken in Belgium, the Lame of water past in the basin is assembled to 818 millimetres, which can be regarded as very high. The specific Débit (Qsp) of the river is thus of 25,92 liters a second and per square kilometer of basin.

In Haulmé in France

The flow of Semoy was observed during 42 years (1965-2007), at the hydrometric station of Haulmé, locality of the department of the the Ardennes located little before its confluence with the Meuse. The studied surface of the river is there of 1 336 km ² (either it quasi totality of the catchment area which makes 1 350 km ²). The figures obtained are lower by more or less 20% than those obtained with Bohan, in Belgium, but that should not surprise, the duration of observation being 42 years in Haulme, against only 10 years with Bohan.

The interannual medium flow or module of the river with Haulmé is of 29,6 m ³ a second.

Semoy presents seasonal fluctuations of flow marked well, like often in the North-East of France. The high waters are held in winter and are characterized by average monthly flows oscillating between 41,10 and 64,0 m ³ a second, from December to March included (with an in January maximum). As of March however the river starts its fall (50,8 in February and 41,1 in March), and the flow drops gradually throughout the spring and by the beginning of the summer until the period of low waters. Those have in August place and in September, with a floor of 8,47 m ³ in August, follow-up of 8,83 m ³ a second in September. As from October, the monthly medium flow inflates quickly (19,1 m ³ already this month). But the fluctuations are much more marked over short periods, and vary according to the years.

With the low water level, the VCN3 can fall until 1,6 m ³, in the event of dry period quinquennial, which can be regarded as severe for a river of this importance, but is perfectly normal in the of the Ardennes context (see note).

The risings, as for them, can be very important, rather general characteristic of the Walloon rivers and especially inhabitant of the Ardennes. The QIX 2 and QIX 5 or calculated flows of biennial and quinquennial rising are worth respectively 260 and 360 m ³ a second. The QIX 10 or calculated flow of decennial rising is of 430 m ³ a second, the QIX 20 of 500 m ³ and the QIX 50 of 580 m ³ a second (see note). I.e. every 2 years, one must expect a rising of about 260 m ³ a second, which represents about the medium flow from the Meuse in Liege.

The maximum instantaneous flow recorded at the station of Haulmé was of 588 m ³ a second on December 21st, 1993, while the value maximum day laborer was of 516 m ³ a second the day following December 22nd. If one compares the first of these values on a QIX scale of the river, one notes that this rising of December 1993 of order cinquantennal and rather exceptional, was thus intended to repeat oneself only every fifty years on average.

To have an idea of the importance of these flows, one can compare them with the large affluent of the Seine in the south-east of Paris, the Marne in Gournay-sur-Marne in the Paris and its suburbs, famous for the concern which it sometimes causes with Parisian, equipped with a basin more than nine times vaster, and medium flow nearly four times superior. The QIX 10 of the Marne at the end of the course is worth only 510 m ³ (against 430 for Semoy) and its QIX 50 is assembled to 650 m ³ (against 580 for Semoy). Thus in spite of a less vast basin more than nine times and a medium flow of a little more of the quarter, the volume of believed of Semoy reaches more than 80% of those of the Marne.

Semoy is a very abundant river, supplied with such abundant precipitations they, in the area of the solid mass of the Ardennes above all (Cross-Scaille). The Lame of water past in its catchment area is of 702 millimetres annually, which is very high, more twice the higher than the overall average of France all confused basins, and superior also with the average of the French basin of the Meuse (450 millimetres with Chooz, a little upstream of Givet). The specific Flow of the river (or Qsp) reached the high figure of 22,2 liters a second and per square kilometer of basin.

References

Internal bonds

the Area catchment of the Meuse
the Ourthe
the Coal

External bonds

tobacco of Semois on Smokers of pipe
Walloon catchment Areas - Coding and surface
Hydro Bank - Semoy with Haulmé
DIREN - Flows characteristic of the Meuse
Flows characteristic of Semoy

Random links: