HydroBASINS lev08 watershed · #2080373940
Bassin de River Irfon
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 : Carmarthenshire, Powys
Sub-basin area
289,8km²
Upstream area
289,8km²
Discharge
11,64m³/s
Mean elev.
328m
Administrative coverage
Hydrographic chain
▼ Drains into
▲ Receives from 0 basins
Source / headwater (no upstream basin)
2 dept-equivalent regions (GADM L2)
- Powys290.2 km²99.8% of basin
- Carmarthenshire0.7 km²0.2% of basin
25 intersecting protected areas
Elenydd
IUCN IVSite of Special Scientific Interest
23.29 km² overlap
Elenydd - Mallaen
IUCN Not ReportedEmerald Network
23.23 km² overlap
Elenydd
IUCN Not ReportedEmerald Network
3.48 km² overlap
River Wye/ Afon Gwy
IUCN Not ReportedEmerald Network
1.77 km² overlap
Afon Irfon
IUCN IVSite of Special Scientific Interest
1.76 km² overlap
Nant Irfon
IUCN IVNational Nature Reserve
1.38 km² overlap
Waen Rydd
IUCN IVSite of Special Scientific Interest
0.92 km² overlap
Mynydd Epynt
IUCN IVSite of Special Scientific Interest
0.67 km² overlap
Allt-Y-Gest
IUCN IVSite of Special Scientific Interest
0.27 km² overlap
16 more protected areassorted by overlap area
Coed Y Ciliau
IUCN IVSite of Special Scientific Interest
0.16 km² overlap
Llwyn-Cus
IUCN IVSite of Special Scientific Interest
0.14 km² overlap
Mynydd Epynt
IUCN Not ReportedEmerald Network
0.13 km² overlap
Mynydd Epynt
IUCN IVSite of Special Scientific Interest
0.13 km² overlap
Rhos Pant-Tyle
IUCN IVSite of Special Scientific Interest
0.12 km² overlap
Blaen Cilieni
IUCN IVSite of Special Scientific Interest
0.12 km² overlap
Caeau Ty'N-Llwyni
IUCN IVSite of Special Scientific Interest
0.08 km² overlap
Caeau Llwyn Gwrgan
IUCN IVSite of Special Scientific Interest
0.06 km² overlap
Llwynderw
IUCN IVSite of Special Scientific Interest
0.06 km² overlap
Tyncoed Pasture
IUCN IVSite of Special Scientific Interest
0.04 km² overlap
Llofft-Y-Bardd
IUCN IVSite of Special Scientific Interest
0.04 km² overlap
Vicarage Meadows
IUCN IVSite of Special Scientific Interest
0.04 km² overlap
Cwm Craig-Ddu Quarry
IUCN IVSite of Special Scientific Interest
0.01 km² overlap
Garth Bank Quarry
IUCN IVSite of Special Scientific Interest
0.00 km² overlap
Cae Pwll-Y-Bo
IUCN IVSite of Special Scientific Interest
0.00 km² overlap
Llangammarch Wells Quarry
IUCN IVSite of Special Scientific Interest
0.00 km² overlap
Computed live · GADM 4.1 × HydroBASINS lev08 × WDPA · cached after first hit.
Species present
3 599 distinct species · 91 263 observations
Source: GBIF Occurrence snapshot 2026-05-01.
Ecological tissue
Sample of 31 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 Irfon : 20 espèces dont 1 patrimoniale (LR IUCN CR/EN/VU) reliées par 79 interactions GloBI sur 5 types (connectance 14.1%, filtre Serrano α=0.2). 14 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°
8,1°C
Annual rain
1 485mm
Moisture idx (CMI)
0,61
Runoff
1 159mm/an
PET
582mm
AET
551mm
Mean slope
7,3°
Water table
300cm
Forest
9%
Crops
6%
Urban
0%
Protected
9%
HydroATLAS BasinATLAS v10 (Linke et al. 2019) · HydroBASINS lev08 (Lehner & Grill 2013)