HydroBASINS lev08 watershed · #2080432590
Bassin de la Semois
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 3 administrative regions across 2 countries : Ardennes, Luxembourg, Namur
Sub-basin area
1 335,1km²
Upstream area
1 335,1km²
Discharge
17,79m³/s
Mean elev.
385m
Administrative coverage
Hydrographic chain
▼ Drains into
▲ Receives from 0 basins
Source / headwater (no upstream basin)
3 dept-equivalent regions (GADM L2)
- 1086.0 km²81.1% of basin
- 160.2 km²12.0% of basin
- 93.4 km²7.0% of basin
14 communes (GADM L5)Available for FRA, RWA
- Thilay32.83 km²90% commune
- Les Hautes-Rivières30.44 km²97% commune
- Monthermé7.76 km²24% commune
- Fleigneux5.82 km²42% commune
- Villers-Cernay4.27 km²19% commune
- Haulmé3.51 km²100% commune
- Gespunsart3.01 km²14% commune
- Illy1.61 km²10% commune
- Tournavaux1.47 km²100% commune
- La Chapelle0.88 km²12% commune
- Bogny-sur-Meuse0.86 km²4% commune
- Francheval0.63 km²3% commune
- Saint-Menges0.20 km²2% commune
- Neufmanil0.05 km²1% commune
30 intersecting protected areas
National park - core area
206.45 km² overlap
Plateau ardennais
IUCN Not ReportedSpecial Protection Area (Birds Directive)
90.55 km² overlap
Ardennes
IUCN VRegional Nature Park
79.90 km² overlap
Forêt d'Anlier
IUCN Not ReportedSpecial Protection Area (Birds Directive)
74.23 km² overlap
Forêt d'Anlier
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
74.23 km² overlap
Bassin de la Semois de Florenville à Auby
IUCN Not ReportedSpecial Protection Area (Birds Directive)
51.97 km² overlap
Bassin de la Semois de Florenville à Auby
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
51.97 km² overlap
Bassin de la Semois entre Tintigny et Jamoigne
IUCN Not ReportedSpecial Protection Area (Birds Directive)
30.64 km² overlap
Bassin de la Semois entre Tintigny et Jamoigne
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
30.64 km² overlap
21 more protected areassorted by overlap area
Basse-Vierre
IUCN Not ReportedSpecial Protection Area (Birds Directive)
29.07 km² overlap
Basse-Vierre
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
29.07 km² overlap
Bassin de la Semois de Jamoigne à Chiny
IUCN Not ReportedSpecial Protection Area (Birds Directive)
22.35 km² overlap
Bassin de la Semois de Jamoigne à Chiny
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
22.35 km² overlap
Camp militaire de Lagland
IUCN Not ReportedSpecial Protection Area (Birds Directive)
22.10 km² overlap
Camp militaire de Lagland
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
22.10 km² overlap
Bassin de la Semois de Etalle à Tintigny
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
21.57 km² overlap
Bassin de la Semois de Etalle à Tintigny
IUCN Not ReportedSpecial Protection Area (Birds Directive)
21.57 km² overlap
Vallée de la Semois en aval d'Alle
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
18.01 km² overlap
Vallée de la Semois en aval d'Alle
IUCN Not ReportedSpecial Protection Area (Birds Directive)
18.01 km² overlap
Marais de la Haute-Semois et Bois de Heinsch
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
17.28 km² overlap
Marais de la Haute-Semois et Bois de Heinsch
IUCN Not ReportedSpecial Protection Area (Birds Directive)
17.28 km² overlap
Bassin de la Semois de Bouillon à Alle
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
16.69 km² overlap
Bassin de la Semois de Bouillon à Alle
IUCN Not ReportedSpecial Protection Area (Birds Directive)
16.69 km² overlap
Vallées du Ruisseau de Mellier et de la Mandebras
IUCN Not ReportedSpecial Protection Area (Birds Directive)
15.71 km² overlap
Vallées du Ruisseau de Mellier et de la Mandebras
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
15.71 km² overlap
Forêts de la vallée de la Semoy a Thilay et Hautes-rivières
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
9.47 km² overlap
Bassin de la Semois du Maka à Bouillon
IUCN Not ReportedSpecial Protection Area (Birds Directive)
8.90 km² overlap
Bassin de la Semois du Maka à Bouillon
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
8.90 km² overlap
Vallée du Ruisseau des Aleines
IUCN Not ReportedSpecial Protection Area (Birds Directive)
7.52 km² overlap
Vallée du Ruisseau des Aleines
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
7.52 km² overlap
Computed live · GADM 4.1 × HydroBASINS lev08 × WDPA · cached after first hit.
Species present
7 317 distinct species · 235 416 observations
Source: GBIF Occurrence snapshot 2026-05-01.
Ecological tissue
Sample of 41 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 Semois : 29 espèces reliées par 115 interactions GloBI sur 5 types (connectance 13.4%, filtre Serrano α=0.2). 13 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°
8,5°C
Annual rain
1 062mm
Moisture idx (CMI)
0,31
Runoff
404mm/an
PET
726mm
AET
613mm
Mean slope
4,7°
Water table
248cm
Forest
67%
Crops
10%
Urban
1%
Protected
25%
HydroATLAS BasinATLAS v10 (Linke et al. 2019) · HydroBASINS lev08 (Lehner & Grill 2013)