Seine River

Content Cover Image

Seine in central Paris, looking downstream. @ C.Michael Hogan

The Seine River, often termed simply the Seine, is the second longest river in France after the Loire, extending a length of 776 kilometres (482 miles) before discharging to the English Channel near L'Havre. It flows through the capital city of Paris.

The preponderance of the Seine Basin is considerably disturbed by human activities, especially agriculture, leading to degradation of water quality and adverse impacts to both terrestrial and aquatic species in the basin.

Extensive navigational use of the Seine has been made since ancient times, clearly evidenced by early Gauls and Romans; its navigational value was not lost on the invading Danish Vikings, who had advanced considerably upriver by the late ninth century AD.

caption Marne River, a tributary of the Upper Seine. Source: Paul Cezanne. 1888 The Seine has a basin area of approximately 78,650 square kilometres, and drains a portion of Belgium as well as France.


The river rises near Dijon in Burgundy. Chief tributaries of the Seine include the Aisne, Aube, Barse, Eure, Orge, Yvette, Loing, Marne, Oise, Epte, Risle and Yonne.

Historically the Seine has been viewed to have four chief reaches:

  • the Little Seine encompasses headwaters downriver to the confluence with the Yonne;
  • the Upper Seine continues the course and spans the distance from Montereau to Paris, not quite reaching the point of confluence with the Marne;
  • the Lower Seine extends from Paris to St. Aubin, the lower point being the limit of tidal influence; and finally,
  • the Tidal Seine extends from St. Aubin to the English Channel.

The Marne and Yonne exhibit the greatest torrential flows, due to the percentage of their courses underlain by impermeable strata, in combination with the river gradients. Although the Loing manifests the highest percentage of impermeable strata of all the tributaries, its low gradient mitigates against torrential velocities. Thus the majority of the Seine and its tributaries exhibit a relaxed generally even flow rate.

caption Seine catchment basin. U.S.Geological Survey

Source: Earth Snapshot

Water quality

Seine water pollutant loads of heavy metals, nutrients, sediment and bacteria are relatively high, especially influnced by wastewater and surface runoff from Paris and its suburbs. Parisian pollutant loadings are noted to be particularly high during periods of high rainfall, not only due to high runoff, but also from the inadequate sewage treatment facilities in periods of high combined wastewater/stormwater flow.

Heavy metal concentrations at Poses weir reveal the following levels: copper, 1.9 milligrams per liter; cadmium, 32 mg/l; and lead, 456 mg/l. Concentrations of zinc are also quite high, making the Seine Estuary one of the most highly contaminated estuaries in the world with respect especially to lead and cadmium. Significant amounts of toxic pollutants are also attached to sediments deposited in the Seine during the last two centuries, including mercury, nickel, chromium, toluene, DDT and a variety of herbicides and pesticides.

Downriver from Paris, significant quantites of ammonium are discharged into the Seine from effluent of the Achères wastewater treatment plant.

Aquatic biota

caption Northern pike, one of the larger fish in the Seine. @ Karel Jakubec There are a total of 37 fish species inhabiting the Seine, and another two taxa that are known to have been extirpated in modern times. Two of the largest aquatic fauna known to have lived in the Seine are now locally extinct: the 500 centimeter (cm) long sturgeon (Acipenser sturio) and the 83 cm long allis shad (Alosa alosa).

The largest extant native demersal (species living on or near the river bottom) taxa in the Seine are:

  • the 133 cm European eel (Anguilla anguilla);
  • the 150 cm northern pike (Esox lucius);
  • the 120 cm sea lamprey (Petromyzon marinus); and,
  • the 152 cm Burbot (Lota lota).

The largest bentho-pelagic species occurring in the Seine are:

  • the introduced 105 cm silver carp (Hypophthalmichthys molitrix);
  • the native 120 cm barbel (Hypophthalmichthys molitrix);
  • the native 150 cm Atlantic salmon (Salmo salar); and,
  • the native 500 cm Wels catfish (Silurus glanis).

There are several extant native pelagic-neritic (coastal brackish) fish species in the Seine:

  • the 73 cm long twaite shad (Alosa fallax);
  • the 59 cm golden grey mullet (Liza aurata);
  • the 171 cm sea trout (Salmo trutta trutta); and,
  • the 45 cm European smelt (Osmerus eperlanus).

Terrestrial ecoregions

The ecoregion encompassing the lower Seine catchment area is known as the Atlantic mixed forests. The mammalian fauna of this ecoregion is chiefly composed of species widely occurring in Europe: red deer (Cervus elaphus), fallow deer (Dama dama), roe deer (Capreolus capreolus), badger (Meles meles), stone marten (Martes foina), and pine marten (Martes martes). Several of the mammals found in the ecoregion are listed on the International Union for Conservation of Nature and Natural Resources (IUCN) Red List, including European otter (Lutra lutra), European mink (Mustela lutreola), and several taxa of bat (Rhinolophus euryale, R. hipposideros, Barbastella barbastellus, Myotis bechsteini, M. dasycneme, and M. emarginatus).

The upper Seine watershed is occupied by the Western European broadleaf forests ecoregion, found through the middle of France.  Warm, moist air from the Atlantic Ocean dominates this inland ecoregion. Small mountains (all less than 1500 meters), hills, and valleys occur throughout the area. Yearly temperatures are steady, precipitation is fairly evenly distributed throughout the year, and frosts occur for one to three months. This ecoregion exhibits notable bird populations, but most of the larger mammals are in decline and have been extirpated from many areas. Throughout this ecoregion, the landscape is dominated by urbanization and agriculture, including vineyards and other monocultural plantings. Most tributaries of the Seine have been altered for use in irrigation, and many valleys are flooded by dams constructed for increasing power and water supplies.


The Seine Basin was one of the earliest parts of Europe inhabited by hominids, with stone tools being recovered from the era of 500,000 to 200,000 years before present. Some of these artefacts, oftern termed Abbevillian, derive from Chelles, a present day suburb of Paris along the Seine. These early tools are attributed to Neanderthal ancestors, rather than Homo sapiens.

caption Regional map depicting the Seine, with appellations of the Roman era. Before Roman times the Seine was used by the Gauls for navigation as well as a settlement locus. In the year 52 BC Julius Caesar led the Roman army to a defeat of King Vercingetorix of the Gauls at Alesia; in that same year, the Romans established the colony of Leuticia on an island in the Seine (Ile de la Cita). There are extant labyrinthine ruins of Leuticia readily viewable today. The Roman name for the Seine was Sequana, a river that flowed through the Roman province of Gallia Lugdunensis. Danish Vikings used the Seine for marauding attacks that sacked numerous villages extending considerably upriver by the 870s AD.

The mouth of the Seine near L'Havre marks a key staging area where land troops from Spain were to meet with the ill-fated Spanish Armada in the year 1588. Due to stormy seas and harassment from the English fleet, the rendezvous was not successfully accomplished, altering modern sea supremacy.


  • caption Subterranean Roman ruins of Leuticia on an island in the Seine, Paris. S.Carpentier, L.Moilleron, C.Beltran, D.Herve and D.Thevenot. 2002. Quality of dredged material in the River Seine Basin (France) II. Micropollutants. Elsevier. The Science of Total Environment. 299: 57-72
  • J.F.Chiffoleau. 2007. Metal contamination. the Seine-Aval scientific programme. Quae. 40 pp.
  • FishBase. 2002. Species in the Seine
  • E.Ledoux, E.Gomez, J.M.Monget, C.Viavattene, P.Viennot, A.Ducharne, M.Benoit, C.Mignolet, C.Schott and B.Mary. 2007. Agriculture and groundwater nitrate contamination in the Seine basin. The STICS-MODCOU modelling chain. Sci Total Environ. 2007 Apr 1;375(1-3):33-47.
  • Jacques de Morgan. 1944. Prehistoric man: A general outline of prehistory. Taylor & Francis. 304 pp.
  • Martin Seidl. 1997. The fate of organic matter in river Seine after a combined sewer overflow. ENPC. University Paris Val de Marne Paris XII (France) 181 pp.
  • Mathieu Sebilo, Gilles Billen, Bernhard Mayer, Daniel Billiou, Micheline Grably, Josette Garnier and André Mariotti. 2006. Assessing Nitrification and Denitrification in the Seine River and Estuary Using Chemical and Isotopic Techniques Volume 9, Number 4, 564-577
  • Leveson Francis Vernon-Harcourt. 1886. The River Seine. books.google.com 154 pages
  • World Wildlife Fund. 2002. Atlantic mixed forests


Hogan, C. (2012). Seine River. Retrieved from http://www.eoearth.org/view/article/174365


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