HydroBASINS lev08 watershed · #4080044580
Bassin de 栗山川
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 8 administrative regions : Asahi, Katori, Narita, Sanmu, Shibayama +3
Sub-basin area
262,4km²
Upstream area
262,4km²
Discharge
5,55m³/s
Mean elev.
26m
Administrative coverage
8 dept-equivalent regions (GADM L2)
- 73.5 km²28.0% of basin
- 62.6 km²23.9% of basin
- YokoshibahikariChiba · Japan49.0 km²18.7% of basin
- 32.6 km²12.4% of basin
- 26.9 km²10.2% of basin
- 12.7 km²4.8% of basin
- 5.0 km²1.9% of basin
- AsahiChiba · Japan0.1 km²0.0% of basin
7 intersecting protected areas
Tako machi
IUCN IVPrefectural Wildlife Protection Area
13.73 km² overlap
Iidaka toyowa
IUCN IVPrefectural Wildlife Protection Area
3.61 km² overlap
Sosa shi
IUCN IVPrefectural Wildlife Protection Area
0.33 km² overlap
GreenPort Eco Agripark
IUCN Not ApplicableOECM
0.16 km² overlap
Iidakadanrin no mori
IUCN VLocal Environment Conservation Area(Chiba)
0.07 km² overlap
Kujukuri
IUCN VPrefectural Natural Park
0.05 km² overlap
Local Environment Conservation Area(Chiba)
0.05 km² overlap
Computed live · GADM 4.1 × HydroBASINS lev08 × WDPA · cached after first hit.
Species present
1 353 distinct species · 6 255 observations
Source: GBIF Occurrence snapshot 2026-05-01.
Ecological tissue
Sample of 10 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 栗山川 : 10 espèces reliées par 8 interactions GloBI sur 4 types (connectance 10.3%, filtre Serrano α=0.2). 3 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°
14,7°C
Annual rain
1 514mm
Moisture idx (CMI)
0,39
Runoff
676mm/an
PET
924mm
AET
914mm
Mean slope
1,8°
Water table
45cm
Forest
25%
Crops
41%
Urban
18%
Protected
7%
HydroATLAS BasinATLAS v10 (Linke et al. 2019) · HydroBASINS lev08 (Lehner & Grill 2013)