HydroBASINS lev08 watershed · #2080050420

Bassin de River Alt

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 5 administrative regions : Halton, NA, St. Helens

Coastal basin 2% lakePfafstetter: 23301910

Sub-basin area

507,3km²

Upstream area

507,3km²

Discharge

1,54m³/s

Mean elev.

21m

Administrative coverage

5 dept-equivalent regions (GADM L2)

NA
England · United Kingdom
243.6 km²
47.8% of basin
NA
England · United Kingdom
199.4 km²
39.1% of basin
NA
England · United Kingdom
44.0 km²
8.6% of basin
Halton
England · United Kingdom
9.6 km²
1.9% of basin
St. Helens
England · United Kingdom
2.5 km²
0.5% of basin

30 intersecting protected areas

Ribble & Alt Estuaries
IUCN Not Reported
Wetland of International Importance (Ramsar Site)
25.97 km² overlap
Sefton Coast
IUCN IV
Site of Special Scientific Interest
18.63 km² overlap
Sefton Coast
IUCN Not Reported
Emerald Network
18.20 km² overlap
Ribble and Alt Estuaries
IUCN Not Reported
Emerald Network
15.69 km² overlap
Ribble Estuary
IUCN IV
Site of Special Scientific Interest
12.26 km² overlap
Ribble Estuary
IUCN IV
National Nature Reserve
11.37 km² overlap
Mersey Estuary
IUCN IV
Site of Special Scientific Interest
5.19 km² overlap
Mersey Estuary
IUCN Not Reported
Emerald Network
3.83 km² overlap
Mersey Estuary
IUCN Not Reported
Wetland of International Importance (Ramsar Site)
3.81 km² overlap

21 more protected areassorted by overlap area

Ribble and Alt Estuaries
IUCN Not Reported
Marine Protected Area (OSPAR)
3.60 km² overlap
Ainsdale Sand Dunes
IUCN IV
National Nature Reserve
3.59 km² overlap
Mersey Estuary
IUCN Not Reported
Marine Protected Area (OSPAR)
2.98 km² overlap
Ainsdale and Birkdale Hills
IUCN IV
Local Nature Reserve
2.94 km² overlap
Formby
IUCN V
Nature Reserve
1.91 km² overlap
Ribble Estuary
IUCN IV
Marine Conservation Zone
1.85 km² overlap
Liverpool Bay / Bae Lerpwl
IUCN Not Reported
Emerald Network
1.64 km² overlap
Martin Mere
IUCN Not Reported
Wetland of International Importance (Ramsar Site)
1.20 km² overlap
Martin Mere
IUCN Not Reported
Emerald Network
1.20 km² overlap
Martin Mere, Burscough
IUCN IV
Site of Special Scientific Interest
1.20 km² overlap
Marshside
IUCN IV
Nature Reserve
1.10 km² overlap
Croxteth
IUCN IV
Local Nature Reserve
0.87 km² overlap
Ravenmeols Hills
IUCN IV
Local Nature Reserve
0.74 km² overlap
Speke Hall
IUCN V
Nature Reserve
0.54 km² overlap
Mere Sands Wood
IUCN IV
Site of Special Scientific Interest
0.43 km² overlap
Cabin Hill
IUCN IV
National Nature Reserve
0.28 km² overlap
Mersey Narrows and North Wirral Foreshore
IUCN Not Reported
Emerald Network
0.26 km² overlap
Mersey Narrows
IUCN IV
Site of Special Scientific Interest
0.26 km² overlap
Millwood & Alder Wood
IUCN IV
Local Nature Reserve
0.23 km² overlap
Downholland Moss
IUCN IV
Site of Special Scientific Interest
0.22 km² overlap
Allerton (Eric Hardy)
IUCN IV
Local Nature Reserve
0.19 km² overlap

Computed live · GADM 4.1 × HydroBASINS lev08 × WDPA · cached after first hit.

Species present

9 938 distinct species · 1 298 363 observations

Source: GBIF Occurrence snapshot 2026-05-01.

Ecological tissue

Sample of 34 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).

RègnesAnimalPlanteChampignonBacterie

RelationsPredationParasitismeSymbiosePollinisation

StatutEn dangerVulnérableProtégéeEndémique

RègnesAnimalPlanteChampignonBacterie

RelationsPredationParasitismeSymbiosePollinisation

StatutEn dangerVulnérableProtégéeEndémique

Indicateurs du tissu écologique

Tissu écologique de Bassin de River Alt : 22 espèces dont 1 patrimoniale (LR IUCN CR/EN/VU) reliées par 98 interactions GloBI sur 6 types (connectance 17.5%, filtre Serrano α=0.2). 12 bulles taxonomiques (cascade genre/famille GloBI, ≥3 espèces).

Espèces affichées

Interactions affichées

Connectance

0.175

Patrimoniales

Plus dense que (national)0 %(top 100%)

Comparaison sur la connectance du réseau local complet vs distribution nationale (toutes les communes françaises).

Hydroclimate (BasinATLAS lev08)

Mean T°

9,2°C

Annual rain

855mm

Moisture idx (CMI)

0,27

Runoff

670mm/an

PET

620mm

AET

517mm

Mean slope

0,7°

Water table

27cm

Forest

Crops

17%

Urban

48%

Protected

HydroATLAS BasinATLAS v10 (Linke et al. 2019) · HydroBASINS lev08 (Lehner & Grill 2013)