Orne (Moselle)

For the river in Normandy, see Orne (river).

Orne
The Orne flooding at Rombas
Origin	Lorraine
Mouth	Moselle 49°17′15″N 6°10′55″E / 49.2875°N 6.18194°E / 49.2875; 6.18194 (Moselle-Orne)Coordinates: 49°17′15″N 6°10′55″E / 49.2875°N 6.18194°E / 49.2875; 6.18194 (Moselle-Orne)
Basin countries	France
Length	85.8 km
Source elevation	320 m
Avg. discharge	12.4 m³/s
Basin area	1,268 km²

The Orne valley.

The Orne at Rombas.

The Orne is a river in Lorraine, north-eastern France, which is a left tributary of the Moselle and sub-tributary of the Rhine. Its source is in the hills northeast of Verdun. It flows east and joins the Moselle near Mondelange, between Metz and Thionville.

Name

"Orne" may originate from autura (a river, cf. Eure), or onna (a river)^{[citation needed]} as mentioned in Endlicher's glossary of Gallic names De nominibus Gallicis, in which these words are translated into Latin as flumen.

If so, then there is no relationship with the name of the Orne river in Normandy, which is referred to as the Olina by Ptolemy, a homonym of Fluvius Olne, the Orne saosnoise in Sarthe, which Xavier Delamarre^[1] traces back to the Celtic olīnā (elbow).

Geography

The length of the Orne is 85.8 km.^[2] It rises at an altitude of 320 m in d'altitude in the Côtes de Meuse, in the commune of Ornes. It flows through Étain, Conflans-en-Jarnisy, Auboué, Homécourt, Jœuf, Moyeuvre-Grande, Rosselange, Rombas, Clouange, Vitry-sur-Orne, Gandrange and Richemont, where it joins the Moselle at an altitude of 155 m.

Tributaries

The Orne's principal tributaries and subtributaries are:

Ruisseau de Vaux Moulin de Darmont Yron (sub-tributary Longeau)

Rawé Woigot Conroy

The Orne is also fed by water pumped out of the mines at Jarny, Giraumont, Auboué and Orne-Roncourt.

Hydrology

The Orne is a substantial river, similar to its neighbours in the West Lorraine region which rise in the Côtes de Meuse.

Flow rates of the Orne at Rosselange

The Orne's flow rate has been measured over a period of 40 years (1967-2007) at Rosselange, located in the Moselle department a short way upstream of the confluence.^[3] The watershed of the Orne at Rosselange is 1,226 km², almost its entire watershed of 1,268 km².

The mean annual flow rate, or discharge of the river at Rosselange is 12.6 m³/s.

The Orne exhibits strongly marked seasonal fluctuations, such as are very often found in the east of France, with high water in winter/spring bringing the monthly average up to between 20.2 and 26.9 m³/s from December to March inclusive, with a maximum in February. Summer low waters are quite prolonged, from June to early October, with a low monthly average of 2.81 m³/s in September. These monthly figures, however, are just averages, and conceal even more pronounced short-term variation.

Monthly average flow rate in m³/s measured at Rosselange hydrological station
Data taken over a 41 year period

At low water, the 3-year low instantaneous flow rate can drop to 0.56 m³/s, as is seen frequently for rivers of the region.

Flooding of the Orne can be very significant. The maximum instananeous flow rate ever recorded was 318 m³/s on 22 December 2003, while the maximum recorded daily average was 292 m³/s on the preceding day. The Orne's instantaneous maximum flow rate for 2 and 5 years (IMFR2 and IMFR5) are 170 and 230 m³/s respectively; the IMFR10 is 280 m³/s, the IMFR20 is 320 m³/s, and the IMFR50 is 370 m³/s. These figures indicate that the flood of December 2003 was, roughly speaking, a twenty-year event and thus not particularly unusual. The Orne's IMFRs are over half that of the Meurthe, the Moselle's most significant French tributary and whose basin is almost 2.5 time larger.

To compare with a significant river in the Paris basin, the Loing, a river known for its substantial flooding, has has an IMFR10 of 190 m³/s as against 280 m³/s for the Orne, and its IMFR50 reaches only 270 m³/s as against 370 m³/s for the Orne. This is despite the Loing's watershed being three and a half times larger than the Orne.

The Orne is fed by heavy rainfall in the western part of its watershed. The runoff curve number in its watershed is 326 mm annually, which is almost equal to the average of all France, but clearly less than the average in the French part of the Moselle basin (445 mm at Hauconcourt). The specific flow rate reaches 10.3 litres per second per square kilometre of watershed.

Flow rates of members of the Orne basin

Name	Location	Flow rates in m3/s							Côte max(m)	Max. instant.	Max. daily.	Runoff curve no. (mm)	Surface (km2)
		Discharge	VCN3 (low w.)	IMFR2	IMFR5	IMFR10	IMFR20	IMFR50
Ruisseau de Vaux	Morgemoulin	0.417	0.011	9.1	12	13	15	17	1.74	14.8	10.2	312	42
Orne	Boncourt	3.73	0.030	59	84	100	120	140	4.59	125	99.7	286	412
Yron	Jarny	4.01	0.130	82	120	140	170	200	3.53	169	139	332	383
Longeau	Jarny	2.17	-	-	-	-	-	-	-	-	-	320	214
Woigot	Briey	1.25	0.067	16	25	30	35	42	2.67	56.2	23.1	522	76
Orne	Rosselange	12.6	0.560	170	230	270	320	370	3.98	318	292	326	1,226

Related articles

• List of rivers of France
• Moselle

External links

• Characteristic flow rates of the OrnePDF

References

1. ^

   This article is part of the series on: French language

   Langues d'oïl Dialects Creoles Francophonie History Oaths of Strasbourg Ordinance of Villers-Cotterêts Anglo-Norman Grammar Adverbs Articles and determiners Pronouns Personal pronouns Verbs Conjugation Verb morphology Orthography Alphabet Reforms Use of the circumflex Phonology Elision Liaison Aspirated h Wikipedia IPA for French

   This box: view · talk · edit

   Dictionnaire de la langue gauloise, éditions errance 2003. p. 240.
2. ^ SANDRE. "Fiche rivière l'orne (A8--0100)". http://sandre.eaufrance.fr/app/chainage/courdo/htm/A8--0100.php?cg=A8--0100. 
3. ^ Banque Hydro - station A8431010 - L'Orne à Rosselange (option Synthèse) (Do not tick the box "Station en service")

• http://www.geoportail.fr
• The Orne at the Sandre database