HydroBASINS lev08 watershed · #2080455490
Bassin de la Seine
A watershed (drainage basin) is not a body of water — it is the land area where rainfall converges towards a single river that eventually reaches the sea (or an endorheic basin). Boundaries follow ridgelines.
Crosses 2 administrative regions : Val-d'Oise, Yvelines
Sub-basin area
347,7km²
Upstream area
61 656,4km²
Discharge
427,92m³/s
Mean elev.
93m
Administrative coverage
Hydrographic chain
▼ Drains into
▲ Receives from 2 basins
- Bassin de l'Oise1507 km²
- Bassin de la Seine1089 km²
2 dept-equivalent regions (GADM L2)
- 252.2 km²72.3% of basin
- 96.6 km²27.7% of basin
66 communes (GADM L5)Available for FRA, RWA
- Saint-Germain-en-Laye20.68 km²42% commune
- Orgeval15.81 km²100% commune
- Triel-sur-Seine12.83 km²92% commune
- Les Mureaux12.67 km²100% commune
- Poissy12.35 km²95% commune
- Seraincourt12.07 km²100% commune
- Ecquevilly11.36 km²100% commune
- Avernes11.18 km²85% commune
- Verneuil-sur-Seine9.33 km²100% commune
- Sagy9.29 km²82% commune
- Flins-sur-Seine8.83 km²99% commune
- Vaux-sur-Seine8.60 km²97% commune
- Juziers8.59 km²99% commune
- Wy-dit-Joli-Village7.91 km²100% commune
- Longuesse7.80 km²97% commune
- Lainville-en-Vexin7.80 km²100% commune
- Aincourt7.61 km²77% commune
- Morainvilliers7.47 km²100% commune
- Brueil-en-Vexin7.15 km²94% commune
- Condécourt6.99 km²100% commune
- Carrières-sous-Poissy6.84 km²100% commune
- Bouafle6.57 km²100% commune
- Vernouillet6.51 km²100% commune
- Achères6.29 km²64% commune
- Andrésy5.64 km²79% commune
- Frémainville5.31 km²100% commune
- Sailly5.28 km²100% commune
- Chapet5.20 km²100% commune
- Villennes-sur-Seine5.12 km²100% commune
- Aubergenville5.01 km²55% commune
- Gaillon-sur-Montcient5.00 km²100% commune
- Vigny4.85 km²72% commune
- Théméricourt4.84 km²66% commune
- Mézy-sur-Seine4.77 km²100% commune
- Jambville4.77 km²100% commune
- Les Alluets-le-Roi4.23 km²55% commune
- Tessancourt-sur-Aubette4.20 km²100% commune
- Guiry-en-Vexin4.16 km²66% commune
- Gadancourt3.96 km²85% commune
- Oinville-sur-Montcient3.89 km²100% commune
- Menucourt3.58 km²100% commune
- Hardricourt3.53 km²100% commune
- Meulan-en-Yvelines3.52 km²100% commune
- Chanteloup-les-Vignes3.22 km²94% commune
- Médan2.99 km²100% commune
- Drocourt2.99 km²73% commune
- Arthies2.97 km²39% commune
- Montalet-le-Bois2.63 km²100% commune
- Évecquemont2.50 km²100% commune
- Courdimanche2.21 km²38% commune
- Chambourcy2.20 km²27% commune
- Feucherolles1.44 km²11% commune
- Gargenville1.23 km²14% commune
- Aigremont0.94 km²34% commune
- Cléry-en-Vexin0.83 km²17% commune
- Fontenay-Saint-Père0.65 km²5% commune
- Crespières0.54 km²4% commune
- Banthelu0.50 km²6% commune
- Bazemont0.39 km²6% commune
- Maurecourt0.33 km²9% commune
- Boisemont0.29 km²15% commune
- Maudétour-en-Vexin0.24 km²4% commune
- Conflans-Sainte-Honorine0.17 km²2% commune
- Épône0.15 km²1% commune
- Guitrancourt0.02 km²0% commune
- Villers-en-Arthies0.00 km²0% commune
5 intersecting protected areas
Vexin Français
IUCN VRegional Nature Park
152.69 km² overlap
Regional Nature Reserve
0.24 km² overlap
Coteaux et boucles de la seine
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
0.04 km² overlap
Biotope Protection Order
0.03 km² overlap
Le Bout Du Monde
IUCN IVBiotope Protection Order
0.01 km² overlap
Computed live · GADM 4.1 × HydroBASINS lev08 × WDPA · cached after first hit.
Species present
5 431 distinct species · 275 351 observations
Source: GBIF Occurrence snapshot 2026-05-01.
Ecological tissue
Sample of 35 species (selected proportionally per kingdom among those with at least one documented interaction here) to keep the graph readable. Hover for details, click to explore the full ecosystem of a species.
ℹ️ The territory contains many more species than displayed and all their documented interactions: the graph is intentionally the structural skeleton (top-N species by composite local score, edges filtered by Serrano 2009 disparity filter α=0.2).
Indicateurs du tissu écologique
Tissu écologique de Bassin de la Seine : 25 espèces dont 1 patrimoniale (LR IUCN CR/EN/VU) reliées par 125 interactions GloBI sur 6 types (connectance 19.8%, filtre Serrano α=0.2). 11 bulles taxonomiques (cascade genre/famille GloBI, ≥3 espèces).
Comparaison sur la connectance du réseau local complet vs distribution nationale (toutes les communes françaises).
Hydroclimate (BasinATLAS lev08)
Mean T°
10,5°C
Annual rain
634mm
Moisture idx (CMI)
-0,21
Runoff
221mm/an
PET
798mm
AET
533mm
Mean slope
2,8°
Water table
256cm
Forest
8%
Crops
37%
Urban
45%
Protected
44%
HydroATLAS BasinATLAS v10 (Linke et al. 2019) · HydroBASINS lev08 (Lehner & Grill 2013)