- Somme (river)
Infobox River | river_name = Somme
caption = The Somme.
origin =Picardie
mouth =English Channel
coord|50|13|16|N|1|34|0|E|name=English Channel-Somme|display=inline,title
basin_countries =France
length = 245 km
elevation = 85 m
discharge = 35 m³/s
watershed = ±6,000 km²The Somme is ariver inPicardy , northernFrance . The name "Somme" comes from a Celtic word meaning "tranquility". The departmentSomme was named after this river. The river is 245 km long, from its source in the high ground of the former Forest of Arrouaise atFonsommes near Saint-Quentin, to the Bay of the Somme, in theEnglish Channel . It lies in the geologicalsyncline which also forms theSolent . This gives it a fairly constant and gentle gradient.Historical events
*The river is perhaps most famous as a result of the
World War I Battle of the Somme (July 1 ,1916 ).
*The Invasion Fleet of William the Conqueror assembled in the Bay of the Somme atSaint-Valery-sur-Somme , in 1066.
*The river featured in the 1346 withdrawal of Edward III's army, which forded the river at thebattle of Blanchetaque during the campaign which culminated in theBattle of Crécy .
*Crossing the river also featured prominently in the campaign which led to theBattle of Agincourt some 501 years before the 1916 battle.
*The great battles which finally stopped the German advance in theSpring Offensive of 1918 were fought around the valley of the Somme in places like Villers Bretonneux, which marked the beginning of the end of the war.Départements and towns along the river
*
Aisne : Saint-Quentin
*Somme : Ham, Péronne,Corbie ,Amiens ,Abbeville ,Saint-Valery-sur-Somme ,Le Crotoy Main tributaries
Hydrology
The river is characterized by a very gentle gradient and a steady flow. The valley is more or less steep-sided but its bottom is flat with
fen s and pools. These characteristics of steady flow and flooded valley bottom arise from the river's being fed by theground water in thechalk basin in which it lies. At earlier, colder times, from the Günz to the Würm (Beestonian or Nebraskan to Devensian or Wisconsinian) the river has cut down into theCretaceous geology to a level below the modernwater table . The valley bottom has now therefore, filled with water which, in turn, has filled withfen . [http://nl.wikipedia.org/wiki/Afbeelding:Sommebron1986.jpgThis picture] , of the source of the Somme in 1986, shows it when the water table had fallen below the surface of the chalk in which theaquifer lies. Here, the flow of water had been sufficient to keep the fen from forming.[http://maps.google.com/maps?t=k&ll=49.914093,2.609253&spn=1.207956,2.526855&t=k This satellite photograph] shows the fenny valley crossing the chalk to the sea on the left. The sinuous length at the centre of the picture lies downstream from Péronne.
One of the fens, the "Marais de l'Île" is a nature reserve in the town of St.Quentin. The traditional market gardens of
Amiens , the "Hortillonages" are on this sort of land but drained. Once exploited for peat cutting, the fen is now used for fishing and shooting.The construction of the "Canal de la Somme" began in 1770 and reached completion in 1843. It is 156 km long, beginning at St.Simon and opening into the Bay of the Somme. From St.Simon to Froissy (near Bray sur Somme, south of Albert), the canal is alongside the river. Thence to the sea, the river is partly river and partly navigation. From
Abbeville , it is diverted through thesilt ed, formerestuary , toSaint-Valéry-sur-Somme , where the maritime canal, once called the canal du Duc d'Angoulême enters the English Channel.The St.Quentin Canal, famous for the 1918 battle, links the Somme to northern France andBelgium and southward to the Oise. The Canal du Nord also links the Somme to the Oise, at Noyon, thence to Paris.In 2001, the Somme valley was affected by particularly high floods, which were in large part due to a rise in the
water table of the surrounding land.Flow-rate data (external links)
Monthly flow rates (mean over 43 years)
Catchment area 5560 km².
* [http://hydro.rnde.tm.fr/Traitement/Synthese.php?StaCode=E6470910 at Abbeville] .Daily flow rates compared with mean rates for the time of year at Hangest-sur-Somme (m³/s)
Catchment area 4835 km².
*for the year - [http://hydro.rnde.tm.fr/Traitement/Entre2Gene.php?StaCode=E6440910&Annee=1993 1993] . [http://hydro.rnde.tm.fr/Traitement/Entre2Gene.php?StaCode=E6440910&Annee=1994 1994] . [http://hydro.rnde.tm.fr/Traitement/Entre2Gene.php?StaCode=E6440910&Annee=1995 1995] . [http://hydro.rnde.tm.fr/Traitement/Entre2Gene.php?StaCode=E6440910&Annee=1996 1996] . [http://hydro.rnde.tm.fr/Traitement/Entre2Gene.php?StaCode=E6440910&Annee=1997 1997] . [http://hydro.rnde.tm.fr/Traitement/Entre2Gene.php?StaCode=E6440910&Annee=1998 1998] . [http://hydro.rnde.tm.fr/Traitement/Entre2Gene.php?StaCode=E6440910&Annee=1999 1999] . [http://hydro.rnde.tm.fr/Traitement/Entre2Gene.php?StaCode=E6440910&Annee=2000 2000] . [http://hydro.rnde.tm.fr/Traitement/Entre2Gene.php?StaCode=E6440910&Annee=2001 2001] . [http://hydro.rnde.tm.fr/Traitement/Entre2Gene.php?StaCode=E6440910&Annee=2002 2002] . [http://hydro.rnde.tm.fr/Traitement/Entre2Gene.php?StaCode=E6440910&Annee=2003 2003] . [http://hydro.rnde.tm.fr/Traitement/Entre2Gene.php?StaCode=E6440910&Annee=2004 2004] . [http://hydro.rnde.tm.fr/Traitement/Entre2Gene.php?StaCode=E6440910&Annee=2005 2005] .Mean flow rates monthly and daily at Péronne (m³/s)
Catchment area 1294 km².
*for the year - [http://hydro.rnde.tm.fr/Traitement/Qjm.php?StaCode=E6351410&Annee=1986 1986] . [http://hydro.rnde.tm.fr/Traitement/Qjm.php?StaCode=E6351410&Annee=1987 1987] . [http://hydro.rnde.tm.fr/Traitement/Qjm.php?StaCode=E6351410&Annee=1988 1988] . [http://hydro.rnde.tm.fr/Traitement/Qjm.php?StaCode=E6351410&Annee=1989 1989] . [http://hydro.rnde.tm.fr/Traitement/Qjm.php?StaCode=E6351410&Annee=1990 1990] . [http://hydro.rnde.tm.fr/Traitement/Qjm.php?StaCode=E6351410&Annee=1991 1991] . [http://hydro.rnde.tm.fr/Traitement/Qjm.php?StaCode=E6351410&Annee=1992 1992] . [http://hydro.rnde.tm.fr/Traitement/Qjm.php?StaCode=E6351410&Annee=1993 1993] . [http://hydro.rnde.tm.fr/Traitement/Qjm.php?StaCode=E6351410&Annee=1994 1994] . [http://hydro.rnde.tm.fr/Traitement/Qjm.php?StaCode=E6351410&Annee=1995 1995] . [http://hydro.rnde.tm.fr/Traitement/Qjm.php?StaCode=E6351410&Annee=1996 1996] . [http://hydro.rnde.tm.fr/Traitement/Qjm.php?StaCode=E6351410&Annee=1997 1997] . [http://hydro.rnde.tm.fr/Traitement/Qjm.php?StaCode=E6351410&Annee=1998 1998] . [http://hydro.rnde.tm.fr/Traitement/Qjm.php?StaCode=E6351410&Annee=1999 1999] . [http://hydro.rnde.tm.fr/Traitement/Qjm.php?StaCode=E6351410&Annee=2000 2000] . [http://hydro.rnde.tm.fr/Traitement/Qjm.php?StaCode=E6351410&Annee=2001 2001] . [http://hydro.rnde.tm.fr/Traitement/Qjm.php?StaCode=E6351410&Annee=2002 2002] . [http://hydro.rnde.tm.fr/Traitement/Qjm.php?StaCode=E6351410&Annee=2003 2003] . [http://hydro.rnde.tm.fr/Traitement/Qjm.php?StaCode=E6351410&Annee=2004 2004] . [http://hydro.rnde.tm.fr/Traitement/Qjm.php?StaCode=E6351410&Annee=2005 2005] .References
* Delattre, Ch., Mériaux, E. and Waterlot, M. "Guides Géologiques Régionaux: Région du Nord, Flandre Artois Boulonnais Picardie" (1973)
External links
* [http://www.images-en-somme.net/en/ Pictures from the Somme]
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