HydroBASINS lev08 watershed · #7080754880
Bassin de Onion Creek
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 3 administrative regions : Blanco, Hays, Travis
Sub-basin area
857km²
Upstream area
857km²
Discharge
5,59m³/s
Mean elev.
292m
Administrative coverage
Hydrographic chain
▼ Drains into
▲ Receives from 0 basins
Source / headwater (no upstream basin)
3 dept-equivalent regions (GADM L2)
- 541.7 km²63.3% of basin
- 305.6 km²35.7% of basin
- 8.9 km²1.0% of basin
22 intersecting protected areas
Nicholson Ranch
IUCN VPreserve
2.98 km² overlap
Onion Creek
IUCN VGreenbelt
0.85 km² overlap
Onion Creek
IUCN VWildlife Sanctuary
0.70 km² overlap
Blowing Sink Research Ma
IUCN VCity Preserve
0.67 km² overlap
Nature Preserve
0.60 km² overlap
Latta Branch
IUCN VGreenbelt
0.51 km² overlap
Sunset Valley
IUCN VNatural Area
0.41 km² overlap
Williamson Creek East
IUCN VGreenbelt
0.41 km² overlap
Williamson Creek Central
IUCN VGreenbelt
0.32 km² overlap
13 more protected areassorted by overlap area
Williamson Creek West
IUCN VGreenbelt
0.28 km² overlap
Hielscher Tract
IUCN VGreenbelt
0.27 km² overlap
AARAL Corp.
IUCN VCity Preserve
0.20 km² overlap
South Park Meadows
IUCN VGreenbelt
0.16 km² overlap
Timber Creek
IUCN VCounty Preserve
0.14 km² overlap
Marble Creek
IUCN VGreenbelt
0.12 km² overlap
Old San Antonio
IUCN VGreenbelt
0.11 km² overlap
Deer Park at Maple Run
IUCN VPreserve
0.10 km² overlap
Greenbelt
0.05 km² overlap
Greenbelt
0.05 km² overlap
South Boggy Creek
IUCN VGreenbelt
0.03 km² overlap
Goat Cave Karst
IUCN VNature Preserve
0.03 km² overlap
Lower Blanco River
IUCN VEasement
0.00 km² overlap
Computed live · GADM 4.1 × HydroBASINS lev08 × WDPA · cached after first hit.
Species present
4 885 distinct species · 596 606 observations
Source: GBIF Occurrence snapshot 2026-05-01.
Ecological tissue
Sample of 45 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 Onion Creek : 31 espèces reliées par 93 interactions GloBI sur 4 types (connectance 9.4%, 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°
19,3°C
Annual rain
847mm
Moisture idx (CMI)
-0,42
Runoff
195mm/an
PET
1 470mm
AET
717mm
Mean slope
1,8°
Water table
207cm
Forest
74%
Crops
11%
Urban
20%
Protected
0%
HydroATLAS BasinATLAS v10 (Linke et al. 2019) · HydroBASINS lev08 (Lehner & Grill 2013)