HydroBASINS lev08 watershed · #2080049710
Bassin de River Usk
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 7 administrative regions : Caerphilly, Carmarthenshire, Monmouthshire, NA, Newport +1
Sub-basin area
1 315,8km²
Upstream area
1 315,8km²
Discharge
40,97m³/s
Mean elev.
258m
Administrative coverage
7 dept-equivalent regions (GADM L2)
- Powys743.4 km²56.3% of basin
- Monmouthshire393.5 km²29.8% of basin
- NA127.6 km²9.7% of basin
- Newport40.0 km²3.0% of basin
- Carmarthenshire8.0 km²0.6% of basin
- NA6.1 km²0.5% of basin
- Caerphilly2.3 km²0.2% of basin
30 intersecting protected areas
Bannau Brycheiniog
IUCN VNational Park
626.08 km² overlap
Black Mountains
IUCN IVSite of Special Scientific Interest
41.57 km² overlap
Brecon Beacons
IUCN IVSite of Special Scientific Interest
30.24 km² overlap
Brecon Beacons
IUCN VNature Reserve
14.88 km² overlap
Site of Special Scientific Interest
13.53 km² overlap
Usk Bat Sites/ Safleoedd Ystlumod Wysg
IUCN Not ReportedEmerald Network
13.53 km² overlap
Wye Valley
IUCN VArea of Outstanding Natural Beauty
10.79 km² overlap
Wye Valley (Wales)
IUCN VArea Of Outstanding Natural Beauty
10.79 km² overlap
Blorenge
IUCN IVSite of Special Scientific Interest
9.83 km² overlap
21 more protected areassorted by overlap area
River Usk/ Afon Wysg
IUCN Not ReportedEmerald Network
9.32 km² overlap
Sugar Loaf
IUCN VNature Reserve
8.93 km² overlap
Mynydd Du (Black Mountain)
IUCN IVSite of Special Scientific Interest
5.23 km² overlap
National Nature Reserve
4.89 km² overlap
Site of Special Scientific Interest
4.53 km² overlap
Site of Special Scientific Interest
3.12 km² overlap
Mynydd Llangynidr
IUCN IVSite of Special Scientific Interest
3.00 km² overlap
Llandegfedd Reservoir
IUCN IVSite of Special Scientific Interest
2.41 km² overlap
Tarell Valley
IUCN VNature Reserve
2.40 km² overlap
Brecon Beacons/ Bannau Brycheiniog
IUCN Not ReportedEmerald Network
2.37 km² overlap
Mynydd Epynt
IUCN IVSite of Special Scientific Interest
2.30 km² overlap
Talybont Reservoir
IUCN Not ReportedLocal Nature Reserve
1.95 km² overlap
Site of Special Scientific Interest
1.86 km² overlap
Sugar Loaf Woodlands
IUCN IVSite of Special Scientific Interest
1.74 km² overlap
Sugar Loaf Woodlands
IUCN Not ReportedEmerald Network
1.74 km² overlap
Cwrt Y Bela A Springdale
IUCN IVSite of Special Scientific Interest
1.00 km² overlap
Illtyd Pools
IUCN IVSite of Special Scientific Interest
0.91 km² overlap
Gilwern Hill
IUCN IVSite of Special Scientific Interest
0.81 km² overlap
Craig Y Cilau
IUCN IVNational Nature Reserve
0.65 km² overlap
Skirrid Fawr
IUCN VNature Reserve
0.64 km² overlap
Garn Lakes
IUCN Not ReportedLocal Nature Reserve
0.53 km² overlap
Computed live · GADM 4.1 × HydroBASINS lev08 × WDPA · cached after first hit.
Species present
10 789 distinct species · 766 580 observations
Source: GBIF Occurrence snapshot 2026-05-01.
Ecological tissue
Sample of 28 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 River Usk : 13 espèces reliées par 119 interactions GloBI sur 6 types (connectance 25.6%, filtre Serrano α=0.2). 18 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°
8,7°C
Annual rain
1 196mm
Moisture idx (CMI)
0,46
Runoff
891mm/an
PET
617mm
AET
547mm
Mean slope
7,2°
Water table
311cm
Forest
2%
Crops
12%
Urban
8%
Protected
49%
HydroATLAS BasinATLAS v10 (Linke et al. 2019) · HydroBASINS lev08 (Lehner & Grill 2013)