LTSER Zone Atelier Seine - Estuaire de la Seine - France

The Seine estuary is a megatidal estuary located in northern France. It is the third largest estuarine ecosystem in the country after the Gironde and Loire along the French Atlantic coast; its waters flow into the English Channel. The geographical zone of influence of the Seine estuary runs from just upstream of the Poses dam, at the limit of the tidal penetration into the estuary — 160 km upstream of Le Havre —to the eastern part of the Bay of Seine. It can be divided into three sections: the fresh water upstream section (125 km), the mixing zone characterized by varying salinity levels (35 km), and the marine downstream section under the influence of the Seine River. The megatidal regime generates a turbidity maximum in the ...

Last modified

2024-05-16 10:05:25

General Characteristics and Status

Site Status

Operational

Year Established

1995

Observed properties

Affiliation and Network Specific Information

Affiliation

Photos

seine estuary map

Geographic

Centroid or Representative Coordinates

10 km

10 mi

View in site map

Centroid/Representative Coordinates

Latitude: 49.469905 Longitude: 0.4676948

Size

ca. 215500.00ha

Elevation (average)

0.00msl

Elevation (min)

-20.00msl

Elevation (max)

20.00msl

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Site information [.json]

Centroid/representative coordinates [.shp] [.kml]

Bounding Box [.shp] [.kml]

Boundaries [.shp] [.kml]

Site Details

Ecosystem and Environmental Characteristics

GEO-BON Biome

Coastal

Biome

Coastal

Ecosystem Type

Coastal

Marine

Rivers

Biogeographical Region

Atlantic Bio-geographical Region

EUNIS habitat

Coastal habitats (B)

Coastal habitats (B) » Coastal dunes and sandy shores (B1)

Habitat complexes (X)

Habitat complexes (X) » Bentho-pelagic habitats (X30)

Habitat complexes (X) » Estuaries (X01)

Habitat complexes (X) » Mosaics of mobile and non-mobile substrata in the circalittoral zone (X33)

Habitat complexes (X) » Mosaics of mobile and non-mobile substrata in the infralittoral zone (X32)

Habitat complexes (X) » Mosaics of mobile and non-mobile substrata in the littoral zone (X31)

Inland surface waters (C)

Inland surface waters (C) » Surface running waters (C2)

Inland surface waters (C) » Surface running waters (C2) » Tidal rivers, upstream from the estuary (C2.4)

Marine habitats (A)

Air Temperature: Average Annual

11.00°C

Precipitation Annual

700.00mm

Geology

The Seine estuary was formed at the end of the tertiary era, on rocky substrata dating from the secondary era. The downstream section of the waterway, which wanders through a valley of deeply embanked loops, was established on an undulating plateau caused by the Seine fault. Chalk cliffs, while the outward-curving river margins, dominate the inward-curving river margins; covered in alluvia, form gentle slopes leading down towards the river and the marshes.

Hydrology

The freshwater flow of the river at Poses is relatively small (480 m3.s-1 on average over the last 30 years), with high water volumes over 2220 m3.s-1 (fall/winter) and low water flow under 100 m3.s-1 (at the end of the summer in September).

Protection Level and Land Use

Protection Level (IUCN category)

Category V – Protected Landscape/Seascape/Area

Type, Design and Scale

Site Type

Stationary land-based site

Design of Experimentation

partly experimentation

Scale of Experimentation

plot scale

Design of Observation

mainly observation