HydroBASINS lev08 watershed · #2080569090
Bassin de l'Arrats
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 4 administrative regions : Gers, Haute-Garonne, Hautes-Pyrénées, Tarn-et-Garonne
Sub-basin area
624km²
Upstream area
624,1km²
Discharge
4,72m³/s
Mean elev.
186m
Administrative coverage
Hydrographic chain
▼ Drains into
▲ Receives from 0 basins
Source / headwater (no upstream basin)
4 dept-equivalent regions (GADM L2)
- 552.5 km²88.4% of basin
- 66.1 km²10.6% of basin
- 6.5 km²1.0% of basin
- 0.2 km²0.0% of basin
87 communes (GADM L5)Available for FRA, RWA
- Aubiet36.74 km²93% commune
- Castelnau-Barbarens35.21 km²82% commune
- Mauvezin26.02 km²79% commune
- Monfort23.09 km²100% commune
- Tournecoupe17.75 km²90% commune
- Miradoux17.38 km²49% commune
- Saint-Sauvy16.95 km²100% commune
- Gramont12.78 km²100% commune
- Marsan12.73 km²84% commune
- Lussan12.48 km²95% commune
- Saint-Clar12.10 km²66% commune
- Faget-Abbatial11.69 km²66% commune
- Marsac11.50 km²75% commune
- Saint-Antonin11.48 km²100% commune
- Bellegarde11.36 km²83% commune
- Mansonville11.11 km²73% commune
- Flamarens10.82 km²76% commune
- Lartigue10.31 km²69% commune
- Sainte-Gemme10.25 km²100% commune
- Saint-Léonard10.13 km²77% commune
- Bivès9.97 km²100% commune
- Saint-Antoine9.70 km²99% commune
- Homps9.34 km²99% commune
- Puycasquier9.32 km²46% commune
- Mauroux8.69 km²90% commune
- Saint-Créac8.36 km²100% commune
- Sère8.22 km²90% commune
- Estramiac8.06 km²78% commune
- Tachoires7.78 km²80% commune
- Ansan7.73 km²100% commune
- Moncorneil-Grazan7.67 km²100% commune
- Bézues-Bajon7.54 km²58% commune
- Aussos7.38 km²88% commune
- Sainte-Marie7.35 km²33% commune
- Manent-Montané7.26 km²100% commune
- Cadeilhan7.18 km²82% commune
- Lachapelle7.09 km²67% commune
- Saint-Cirice7.07 km²77% commune
- Haulies7.07 km²69% commune
- Poupas6.79 km²66% commune
- Mansempuy6.74 km²100% commune
- L'Isle-Arné6.60 km²100% commune
- Plieux6.07 km²50% commune
- Monferran-Plavès5.53 km²49% commune
- Avezan5.37 km²100% commune
- Maravat5.31 km²77% commune
- Traversères5.29 km²48% commune
- L'Isle-Bouzon5.21 km²33% commune
- Mont-d'Astarac5.03 km²61% commune
- Labrihe5.02 km²53% commune
- Saint-Blancard4.90 km²33% commune
- Peyrecave4.82 km²100% commune
- Bajonnette4.81 km²69% commune
- Gaudonville4.60 km²64% commune
- Saint-Brès4.39 km²75% commune
- Auvillar4.33 km²28% commune
- Crastes4.17 km²21% commune
- Cabas-Loumassès4.16 km²100% commune
- Saint-Loup4.03 km²29% commune
- Lamaguère3.97 km²59% commune
- Augnax3.63 km²100% commune
- Saint-Caprais3.40 km²44% commune
- Blanquefort3.40 km²100% commune
- Nougaroulet3.32 km²21% commune
- Sérempuy3.21 km²100% commune
- Pouy-Loubrin3.19 km²32% commune
- Arrouède2.79 km²41% commune
- Thermes-Magnoac2.74 km²25% commune
- Lalanne-Arqué2.57 km²23% commune
- Betcave-Aguin2.56 km²25% commune
- Solomiac2.22 km²16% commune
- Sariac-Magnoac1.79 km²16% commune
- Casterets1.68 km²97% commune
- Castéron1.41 km²12% commune
- Meilhan1.39 km²22% commune
- Bardigues1.34 km²12% commune
- Castet-Arrouy0.90 km²12% commune
- Masseube0.63 km²3% commune
- Betbèze0.29 km²8% commune
- Juilles0.23 km²2% commune
- Monties0.20 km²2% commune
- Boulogne-sur-Gesse0.19 km²1% commune
- Pessan0.19 km²1% commune
- Sarcos0.05 km²1% commune
- Sistels0.03 km²0% commune
- Pessoulens0.03 km²0% commune
- Escornebœuf0.02 km²0% commune
3 intersecting protected areas
Vallée et coteaux de la Lauze
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
17.20 km² overlap
bois d\'aguin
IUCN IVLand acquired by a regional conservatory of natural areas
0.10 km² overlap
espace naturel du fenouilla
IUCN IVLand acquired by a regional conservatory of natural areas
0.06 km² overlap
Computed live · GADM 4.1 × HydroBASINS lev08 × WDPA · cached after first hit.
Species present
3 488 distinct species · 70 632 observations
Source: GBIF Occurrence snapshot 2026-05-01.
Ecological tissue
Sample of 45 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 l'Arrats : 40 espèces + 5 bulles famille, 104 interactions GloBI documentées sur 5 types (connectance 10.5%, filtre Serrano α=0.2). Les 5 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°
12,3°C
Annual rain
758mm
Moisture idx (CMI)
-0,22
Runoff
244mm/an
PET
978mm
AET
640mm
Mean slope
3,5°
Water table
231cm
Forest
0%
Crops
86%
Urban
0%
Protected
0%
HydroATLAS BasinATLAS v10 (Linke et al. 2019) · HydroBASINS lev08 (Lehner & Grill 2013)