HydroBASINS lev08 watershed · #2080020630
Bassin de la Seudre
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 : Charente-Maritime, Gironde
Sub-basin area
2 220,2km²
Upstream area
2 220,2km²
Discharge
0,81m³/s
Mean elev.
23m
Administrative coverage
2 dept-equivalent regions (GADM L2)
- 1715.7 km²77.1% of basin
- 447.4 km²20.1% of basin
166 communes (GADM L5)Available for FRA, RWA
- La Tremblade64.37 km²100% commune
- Braud-et-Saint-Louis48.77 km²100% commune
- Saint-Just-Luzac48.10 km²100% commune
- Saint-Georges-d'Oléron47.10 km²100% commune
- Saint-Pierre-d'Oléron42.10 km²100% commune
- Saint-Ciers-sur-Gironde39.39 km²100% commune
- Le Gua37.91 km²100% commune
- Les Mathes37.57 km²100% commune
- Reignac36.72 km²100% commune
- Gémozac32.65 km²100% commune
- Hiers-Brouage32.45 km²100% commune
- Marcillac31.91 km²100% commune
- Saint-Romain-de-Benet31.81 km²97% commune
- Saint-Bonnet-sur-Gironde30.96 km²100% commune
- Saint-Thomas-de-Conac29.73 km²100% commune
- Dolus-d'Oléron29.31 km²100% commune
- Donnezac26.96 km²73% commune
- Meursac26.74 km²100% commune
- Saint-Fort-sur-Gironde25.79 km²100% commune
- Semussac25.36 km²100% commune
- Saint-André-de-Lidon24.27 km²100% commune
- Médis23.80 km²100% commune
- Épargnes23.55 km²100% commune
- Chenac-Saint-Seurin-d'Uzet23.21 km²100% commune
- Saint-Ciers-du-Taillon22.87 km²100% commune
- Mortagne-sur-Gironde22.64 km²100% commune
- Nieulle-sur-Seudre22.42 km²100% commune
- Arces22.21 km²100% commune
- Moëze22.20 km²100% commune
- Sablonceaux22.00 km²100% commune
- Boisredon21.83 km²100% commune
- Saint-Sulpice-de-Royan20.78 km²100% commune
- Marennes20.77 km²100% commune
- Saint-Jean-d'Angle20.58 km²95% commune
- Grézac20.43 km²100% commune
- Arvert20.27 km²100% commune
- Breuillet20.17 km²100% commune
- Royan19.94 km²100% commune
- Saint-Dizant-du-Gua19.55 km²100% commune
- Saint-Androny18.99 km²100% commune
- Saint-Augustin18.85 km²100% commune
- Saujon18.32 km²100% commune
- Mirambeau18.11 km²68% commune
- Champagnolles17.97 km²100% commune
- Lorignac17.68 km²100% commune
- Montendre17.66 km²69% commune
- Corme-Écluse17.61 km²100% commune
- Saint-Trojan-les-Bains17.58 km²100% commune
- Sainte-Gemme17.43 km²42% commune
- Bois17.17 km²83% commune
- Le Château-d'Oléron16.52 km²100% commune
- La Gripperie-Saint-Symphorien16.22 km²87% commune
- Saint-Germain-du-Seudre16.13 km²100% commune
- Saint-Palais-sur-Mer16.04 km²100% commune
- Cozes16.00 km²100% commune
- Meschers-sur-Gironde15.97 km²100% commune
- Saint-Sorlin-de-Conac15.76 km²100% commune
- Saint-Nazaire-sur-Charente15.43 km²80% commune
- Montpellier-de-Médillan15.20 km²100% commune
- Chepniers15.08 km²52% commune
- Courpignac14.99 km²100% commune
- Cravans14.79 km²100% commune
- Rioux14.71 km²78% commune
- Beaugeay14.40 km²100% commune
- Floirac14.26 km²100% commune
- Saint-Sornin14.04 km²100% commune
- Saugon14.02 km²93% commune
- Saint-Georges-de-Didonne14.00 km²100% commune
- Bourcefranc-le-Chapus13.92 km²100% commune
- Anglade13.68 km²100% commune
- Étauliers13.13 km²100% commune
- Saint-Denis-d'Oléron13.09 km²100% commune
- Rouffignac12.86 km²86% commune
- Étaules12.35 km²100% commune
- Le Chay12.28 km²100% commune
- Berson12.18 km²69% commune
- Saint-Girons-d'Aiguevives11.90 km²99% commune
- Saint-Aubin-de-Blaye11.60 km²100% commune
- Cartelègue11.44 km²100% commune
- Saint-Agnant11.41 km²50% commune
- Bourg11.07 km²77% commune
- Cars11.02 km²100% commune
- Saint-Paul10.88 km²100% commune
- Virollet9.74 km²100% commune
- Saint-Palais9.64 km²100% commune
- Mornac-sur-Seudre9.61 km²100% commune
- Thézac9.57 km²76% commune
- Semoussac9.56 km²100% commune
- Générac9.50 km²100% commune
- Saint-Simon-de-Pellouaille9.37 km²99% commune
- Chaillevette9.33 km²100% commune
- Saint-Martial-de-Mirambeau9.01 km²95% commune
- Thaims8.52 km²100% commune
- Barzan8.42 km²100% commune
- Chamouillac8.17 km²100% commune
- Saint-Genès-de-Blaye8.07 km²100% commune
- Soubran7.75 km²61% commune
- Blaye7.58 km²100% commune
- La Brée-les-Bains7.29 km²100% commune
- Brie-sous-Mortagne7.20 km²100% commune
- Port-des-Barques7.03 km²100% commune
- Saint-Ciers-de-Canesse6.99 km²100% commune
- Coux6.70 km²50% commune
- Jussas6.59 km²75% commune
- Plassac6.58 km²84% commune
- Campugnan6.57 km²100% commune
- Rétaud6.52 km²32% commune
- Corignac6.51 km²60% commune
- Saint-Froult6.46 km²100% commune
- Saint-Georges-des-Agoûts6.46 km²100% commune
- Plassac6.36 km²42% commune
- Vaux-sur-Mer6.28 km²100% commune
- Souméras6.18 km²100% commune
- Le Grand-Village-Plage6.14 km²100% commune
- Lansac5.91 km²100% commune
- Salignac-de-Mirambeau5.60 km²71% commune
- L'Éguille5.56 km²100% commune
- Saint-Caprais-de-Blaye5.01 km²100% commune
- Fours4.70 km²100% commune
- Saint-Romain-sur-Gironde4.67 km²100% commune
- Pleine-Selve4.42 km²100% commune
- Sainte-Ramée4.39 km²100% commune
- Tanzac4.30 km²38% commune
- Eyrans4.18 km²100% commune
- Consac4.17 km²47% commune
- Gauriac4.15 km²66% commune
- Talmont-sur-Gironde4.06 km²100% commune
- Mombrier4.06 km²96% commune
- Samonac4.00 km²100% commune
- Saint-Martin-Lacaussade3.88 km²100% commune
- Tauriac3.83 km²35% commune
- Mazion3.76 km²100% commune
- Villeneuve3.54 km²82% commune
- Bayon-sur-Gironde3.53 km²47% commune
- Montlieu-la-Garde3.43 km²11% commune
- Saint-Palais-de-Phiolin3.22 km²29% commune
- Boutenac-Touvent3.03 km²100% commune
- Soubise2.94 km²25% commune
- Saint-Seurin-de-Bourg2.66 km²94% commune
- Givrezac2.64 km²100% commune
- Saint-Trojan2.59 km²82% commune
- Saint-Seurin-de-Cursac2.45 km²100% commune
- Tesson2.15 km²18% commune
- Nancras2.04 km²66% commune
- Villars-en-Pons1.95 km²15% commune
- Saint-Quantin-de-Rançanne1.84 km²19% commune
- Saint-Savin1.80 km²5% commune
- Jazennes1.68 km²16% commune
- Comps1.45 km²100% commune
- Saint-Christoly-de-Blaye1.24 km²4% commune
- Semillac1.06 km²45% commune
- Saint-Genis-de-Saintonge0.83 km²7% commune
- Pugnac0.80 km²6% commune
- Chartuzac0.67 km²32% commune
- Saint-Julien-Beychevelle0.61 km²4% commune
- Saint-Laurent-de-la-Prée0.48 km²2% commune
- Teuillac0.29 km²4% commune
- Tugéras-Saint-Maurice0.22 km²2% commune
- Balanzac0.16 km²1% commune
- Corme-Royal0.15 km²1% commune
- Pisany0.10 km²2% commune
- Fouras0.09 km²1% commune
- Saint-Dizant-du-Bois0.09 km²2% commune
- Rochefort0.08 km²0% commune
- Vergeroux0.04 km²1% commune
- Champagne0.02 km²0% commune
30 intersecting protected areas
Marais de Brouage (et marais nord d'Oléron)
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
156.18 km² overlap
Marais de Brouage-Oléron
IUCN Not ReportedSpecial Protection Area (Birds Directive)
156.18 km² overlap
Estuaire de la Gironde : marais de la rive nord
IUCN Not ReportedSpecial Protection Area (Birds Directive)
122.48 km² overlap
Marais et falaises des côteaux de Gironde
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
122.48 km² overlap
Marais et estuaire de la Seudre, île d'Oléron
IUCN Not ReportedSpecial Protection Area (Birds Directive)
116.10 km² overlap
Marais de la Seudre
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
116.10 km² overlap
Presqu'ile d'Arvert
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
113.91 km² overlap
Marais de Braud-et-Saint-Louis et de Saint-Ciers-sur-Gironde
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
108.41 km² overlap
Marine Nature Park
107.92 km² overlap
21 more protected areassorted by overlap area
Estuaire de la Gironde : marais du Blayais
IUCN Not ReportedSpecial Protection Area (Birds Directive)
68.64 km² overlap
Bonne Anse, marais de Bréjat et de Saint Augustin
IUCN Not ReportedSpecial Protection Area (Birds Directive)
32.93 km² overlap
Dunes et forêts littorales de l'ile d'Oléron
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
29.01 km² overlap
Estuaire de la Gironde
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
27.91 km² overlap
Pertuis charentais - Rochebonne
IUCN Not ReportedSpecial Protection Area (Birds Directive)
20.48 km² overlap
Pertuis charentais - Rochebonne
IUCN Not ReportedMarine Protected Area (OSPAR)
20.04 km² overlap
Pertuis Charentais
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
17.83 km² overlap
Pertuis charentais
IUCN Not ReportedMarine Protected Area (OSPAR)
17.79 km² overlap
Rives de gironde
IUCN IVLand acquired by Conservatoire du Littoral (national seaside and lakeside conservancy)
17.29 km² overlap
Marais de brouage
IUCN IVLand acquired by Conservatoire du Littoral (national seaside and lakeside conservancy)
16.21 km² overlap
Les combots d\'ansoine
IUCN IVLand acquired by Conservatoire du Littoral (national seaside and lakeside conservancy)
10.05 km² overlap
Vallée de la Charente (basse vallée)
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
9.06 km² overlap
Estuaire et basse vallée de la Charente
IUCN Not ReportedSpecial Protection Area (Birds Directive)
9.06 km² overlap
Moëze-Oléron
IUCN IVNational Nature Reserve
8.22 km² overlap
Marais de Moeze
IUCN Not ReportedMarine Protected Area (OSPAR)
8.20 km² overlap
Bonne anse
IUCN IVLand acquired by Conservatoire du Littoral (national seaside and lakeside conservancy)
8.07 km² overlap
Landes de Cadeuil
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
5.70 km² overlap
Marais d\'oleron
IUCN IVLand acquired by Conservatoire du Littoral (national seaside and lakeside conservancy)
3.68 km² overlap
Ile nouvelle
IUCN IVLand acquired by Conservatoire du Littoral (national seaside and lakeside conservancy)
3.23 km² overlap
Landes de Montendre
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
2.51 km² overlap
marais de broue
IUCN IVLand acquired by a regional conservatory of natural areas
2.22 km² overlap
Computed live · GADM 4.1 × HydroBASINS lev08 × WDPA · cached after first hit.
Species present
5 913 distinct species · 724 647 observations
Source: GBIF Occurrence snapshot 2026-05-01.
Ecological tissue
Sample of 30 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 Seudre : 26 espèces dont 2 patrimoniales (LR IUCN CR/EN/VU) + 4 bulles famille, 51 interactions GloBI documentées sur 3 types (connectance 11.7%, filtre Serrano α=0.2). Les 4 bulles regroupent des espèces visuellement absorbées par famille (≥3 espèces visibles).
Comparaison sur la connectance du réseau local complet vs distribution nationale (toutes les communes françaises).
Hydroclimate (BasinATLAS lev08)
Mean T°
12,6°C
Annual rain
870mm
Moisture idx (CMI)
-0,01
Runoff
529mm/an
PET
882mm
AET
631mm
Mean slope
0,9°
Water table
49cm
Forest
9%
Crops
62%
Urban
3%
Protected
3%
HydroATLAS BasinATLAS v10 (Linke et al. 2019) · HydroBASINS lev08 (Lehner & Grill 2013)