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river A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...
Canche (; ) is one of the rivers that flow from the plateau of southern Boulonnais and Picardy, into the
English Channel The English Channel, also known as the Channel, is an arm of the Atlantic Ocean that separates Southern England from northern France. It links to the southern part of the North Sea by the Strait of Dover at its northeastern end. It is the busi ...
, of which the Somme is the largest example. It is long. The basin of the Canche extends to and lies in the south of the département of
Pas-de-Calais The Pas-de-Calais (, ' strait of Calais'; ; ) is a department in northern France named after the French designation of the Strait of Dover, which it borders. It has the most communes of all the departments of France, with 890, and is the ...
. Forming an alluvial valley from wide, the Canche valley also contains
marsh In ecology, a marsh is a wetland that is dominated by herbaceous plants rather than by woody plants.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p More in genera ...
es, meadows and small woods. The gentle gradient, averaging 1.5 percent, gives the river a
meander A meander is one of a series of regular sinuous curves in the Channel (geography), channel of a river or other watercourse. It is produced as a watercourse erosion, erodes the sediments of an outer, concave bank (cut bank, cut bank or river cl ...
ing course. The river rises at Gouy-en-Ternois and passes Frévent, Hesdin, and
Montreuil-sur-Mer Montreuil-sur-Mer (; or ; ), Montreuil-on-the-Sea, is a subprefecture in the Pas-de-Calais Department in northern France. Though commonly called by this name since at least the twelfth century, it was legally known as Montreuil until 31 Decemb ...
before leaving the chalk to flow to the coast between Étaples and Le Touquet-Paris-Plage. Its principal tributaries are the Ternoise, the Planquette, the Créquoise, the Bras de Bronne, the Course, the Dordogne (not to be confused with the
Dordogne Dordogne ( , or ; ; ) is a large rural departments of France, department in south west France, with its Prefectures in France, prefecture in Périgueux. Located in the Nouvelle-Aquitaine region roughly half-way between the Loire Valley and ...
) and the Huitrepin which all join on its right bank, i.e. to the north of the Canche. The lie of the land means there is no notable
tributary A tributary, or an ''affluent'', is a stream or river that flows into a larger stream (''main stem'' or ''"parent"''), river, or a lake. A tributary does not flow directly into a sea or ocean. Tributaries, and the main stem river into which they ...
from the south until the Grande Tringue, which flows from marshland into the small, dredged
estuary An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime enviro ...
.


History

The valley of the Canche has been occupied by man since ancient times because of the productive nature of the land. The unhealthy aspect of marshland means much has been done over the centuries to drain the land efficiently, which has brought about the partial destruction of its original character. The principal activities of the village communities occupying the valley and its surrounds have been (and still are) farming, fishing and reed harvesting.Helga Scarwell et Magalie Franchomme, ''Autour des zones humides : espaces productifs d'hier et conflits d'aujourd'hui'', La revue en sciences de l'environnement: Vertigo, 1 mai 2005
Read online
/ref> The extraction of
peat Peat is an accumulation of partially Decomposition, decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, Moorland, moors, or muskegs. ''Sphagnum'' moss, also called peat moss, is one of the most ...
from the marshes of the lower river was known in the 16th century; peat being the principal means of heating and also a multi-purpose fertilizer. The
alder Alders are trees of the genus ''Alnus'' in the birch family Betulaceae. The genus includes about 35 species of monoecious trees and shrubs, a few reaching a large size, distributed throughout the north temperate zone with a few species ex ...
tree, which grew well in the local marshy soils, contributed to bind the ground, and produced timber. It was realized that
forestry Forestry is the science and craft of creating, managing, planting, using, conserving and repairing forests and woodlands for associated resources for human and Natural environment, environmental benefits. Forestry is practiced in plantations and ...
also helped in drainage. Further developments in the 18th century saw permanent enclosures with animals being fenced-in and property boundaries being created by the planting of hedges and the digging of ditches, contributing to organized and cooperative farming methods. The 18th century also saw the emergence of new perceptions of marshland, long considered as unhealthy places in which to live. Administrative authorities encouraged action to recover the peat marshes by drainage work and the planting of more trees. The reduction of marshland again allowed for even more areas of cultivation to feed the increasing population. During the 19th century, technical progress (for example, the replacement of windmills by steam engines) led to further improvements in drainage, contributing to the drying-up of the valley downstream as far as Hesdin. In the last quarter of the 20th century the authorities became aware of the importance of the marshes and started trying to preserve them, having earlier contributed to their disappearance. The Canche and its valley have been incorporated into a national natural reserve since 1987.The estuary of the Canche


Environmental issues

The Canche
estuary An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime enviro ...
was the first site in northern France where a conservation victory, in respect of the coast, was first achieved, in 1976. Plans had been made to put in place an earlier project, dating from the 1960s, to create an artificial environment on the estuary. The work included creating a harbour and a marina. This was supposed to be “compensation” for extracting the waters of the Canche at Hesdin in order to supply the city of
Lille Lille (, ; ; ; ; ) is a city in the northern part of France, within French Flanders. Positioned along the Deûle river, near France's border with Belgium, it is the capital of the Hauts-de-France Regions of France, region, the Prefectures in F ...
. Of course, this threatened to destroy the rich wildlife and flora of the estuary. The mobilisation of the local inhabitants, various associations and many scientists, after many public enquiries and heated arguments, stopped the plans and left the estuary to nature.The barrage project
on the Fédération Nord-Nature website.


Flora and fauna

With sandbars and spits, the estuary of the Canche is typical of the estuaries of this region of France. The coastal dunes, marshes and valley are home to 485 different plants and a diverse range of wildlife. Seventy-five varieties of resident and migratory birds nest in and around the estuary and valley, such as the nightjar, woodlark, several types of warblers, common snipe, oystercatchers (using rabbit-holes as homes) and the predatory merlin and common buzzard. This area shelters mammals such as deer, wild boar,
red fox The red fox (''Vulpes vulpes'') is the largest of the true foxes and one of the most widely distributed members of the order Carnivora, being present across the entire Northern Hemisphere including most of North America, Europe and Asia, plus ...
es, European badgers, stoats, squirrels, European rabbits and the occasional seal, but, in contrast to the bay of the Somme, the estuary of the Canche does not seem to possess a seal colony. Numerous
amphibian Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excl ...
s ( Common toads, newts and
frog A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...
s) are found in and along the river.


Gallery

Image:frevent01.jpg, The millrace of the Moulin Blonde at Frévent, south of St. Pol Image:Etaples-port.JPG, Étaples - The Canche estuary Image:Common.shelduck.2.arp.750pix.jpg, Common shelduck on the estuary File:Bassin de la Canche.svg, Map of Canche Bassin


See also

* French water management scheme


References

*''Carte Géologique de la France à l'échelle du millionième'' 6th edn. BRGM (2003)


External links


Site de l'Agence de l'eau Bassin Artois-Picardie

Site personnel SAGE de la Canche


{{Authority control Rivers of France Rivers of the Pas-de-Calais Rivers of Hauts-de-France 0Canche