HydroBASINS lev08 watershed · #2080033840
Bassin de Songebekken
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 : Arendal, Froland, Risør, Tvedestrand
Sub-basin area
308,3km²
Upstream area
308,3km²
Discharge
8,39m³/s
Mean elev.
44m
Administrative coverage
4 dept-equivalent regions (GADM L2)
- 143.4 km²46.3% of basin
- 105.9 km²34.2% of basin
- 17.2 km²5.5% of basin
- 0.1 km²0.0% of basin
22 intersecting protected areas
Raet
IUCN Not ReportedNational Park
24.82 km² overlap
Raet og Tromlingene
IUCN Not ReportedEmerald Network
9.26 km² overlap
Fjellheia
IUCN IaNature Reserve
0.79 km² overlap
Nordskogen
IUCN IaNature Reserve
0.55 km² overlap
Gulspettvannet
IUCN IaNature Reserve
0.47 km² overlap
Vennevannsliene
IUCN IaNature Reserve
0.34 km² overlap
Eikåsen
IUCN IaNature Reserve
0.30 km² overlap
Nature Reserve
0.30 km² overlap
Lusemyr
IUCN IaNature Reserve
0.11 km² overlap
13 more protected areassorted by overlap area
Eidbo
IUCN IaNature Reserve
0.09 km² overlap
Ruholmen
IUCN IaNature Reserve
0.09 km² overlap
Bjormyr
IUCN IaNature Reserve
0.05 km² overlap
Rørvikholmene
IUCN IaNature Reserve
0.04 km² overlap
Buøyskjæra
IUCN IaNature Reserve
0.04 km² overlap
Mannskjæret
IUCN IaNature Reserve
0.03 km² overlap
Lille Halsholmen
IUCN IaNature Reserve
0.02 km² overlap
Seilskjærene
IUCN IaNature Reserve
0.02 km² overlap
Stakketoskjæret
IUCN IaNature Reserve
0.01 km² overlap
Skottjern
IUCN IaNature Reserve
0.01 km² overlap
Storskjæret
IUCN IaNature Reserve
0.01 km² overlap
Lille Lestholmen
IUCN IaNature Reserve
0.01 km² overlap
Skuggevik
IUCN Not ReportedNatural Monument
0.00 km² overlap
Computed live · GADM 4.1 × HydroBASINS lev08 × WDPA · cached after first hit.
Species present
9 886 distinct species · 369 688 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).
Indicateurs du tissu écologique
Tissu écologique de Bassin de Songebekken : 27 espèces dont 1 patrimoniale (LR IUCN CR/EN/VU) reliées par 81 interactions GloBI sur 5 types (connectance 13.6%, filtre Serrano α=0.2). 8 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°
7,0°C
Annual rain
945mm
Moisture idx (CMI)
0,47
Runoff
865mm/an
PET
498mm
AET
443mm
Mean slope
4,3°
Water table
189cm
Forest
82%
Crops
12%
Urban
7%
Protected
4%
HydroATLAS BasinATLAS v10 (Linke et al. 2019) · HydroBASINS lev08 (Lehner & Grill 2013)