HydroBASINS lev08 watershed · #1080015290
Bassin de Modder
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 : City of Cape Town, West Coast
Sub-basin area
2 120,1km²
Upstream area
2 120,1km²
Discharge
2,99m³/s
Mean elev.
72m
Administrative coverage
2 dept-equivalent regions (GADM L2)
- 1629.2 km²76.9% of basin
- City of Cape Town405.5 km²19.1% of basin
30 intersecting protected areas
West Coast National Park
IUCN Not ReportedNational Park
306.16 km² overlap
Langebaan Nature Area
IUCN Not ReportedNature Reserve
51.43 km² overlap
Langebaan
IUCN IIWetland of International Importance (Ramsar Site)
29.77 km² overlap
Koeberg Private Nature Reserve
IUCN Not ReportedNature Reserve
26.81 km² overlap
Postberg Nature Reserve
IUCN Not ReportedNature Reserve
24.53 km² overlap
Jakkalsfontein Private Nature Reserve
IUCN Not ReportedNature Reserve
17.83 km² overlap
Witzands Aquifer Nature Reserve
IUCN Not ReportedNature Reserve
17.50 km² overlap
Langebaan Lagoon Marine Protected Area
IUCN Not ReportedMarine Protected Area
15.26 km² overlap
Bokbaai Nature Reserve
IUCN Not ReportedNature Reserve
10.71 km² overlap
21 more protected areassorted by overlap area
Blaauwberg Nature Reserve
IUCN Not ReportedNature Reserve
10.25 km² overlap
Grotto Bay Private Nature Reserve
IUCN Not ReportedNature Reserve
9.64 km² overlap
SAS Saldanha Provincial Nature Reserve
IUCN Not ReportedNature Reserve
9.45 km² overlap
Sixteen Mile Beach Marine Protected Area
IUCN Not ReportedMarine Protected Area
8.85 km² overlap
Swartriet Private Nature Reserve
IUCN Not ReportedNature Reserve
6.79 km² overlap
Dassen Island Nature Reserve
IUCN Not ReportedWetland of International Importance (Ramsar Site)
5.70 km² overlap
Blaauwberg Conservation Area Local Nature Reserve
IUCN Not ReportedNature Reserve
5.58 km² overlap
Hopefield Private Nature Reserve
IUCN Not ReportedNature Reserve
5.43 km² overlap
Robben island Marine Protected Area
IUCN Not ReportedMarine Protected Area
4.28 km² overlap
Groot Paternoster Private Nature Reserve
IUCN Not ReportedNature Reserve
3.42 km² overlap
Blaauw Mountain Private Nature Reserve
IUCN Not ReportedNature Reserve
3.39 km² overlap
Dassen Island Provincial Nature Reserve
IUCN Not ReportedNature Reserve
2.69 km² overlap
Columbine Nature Reserve
IUCN Not ReportedNature Reserve
2.66 km² overlap
Rietvlei Nature Area
IUCN Not ReportedNature Reserve
1.56 km² overlap
Malgas Island Marine Protected Area
IUCN Not ReportedMarine Protected Area
1.04 km² overlap
West Point Private Nature Reserve
IUCN Not ReportedNature Reserve
0.97 km² overlap
Yzerfontein Local Nature Reserve
IUCN Not ReportedNature Reserve
0.94 km² overlap
Jutten Island Marine Protected Area
IUCN Not ReportedMarine Protected Area
0.59 km² overlap
Franco Three Fountatins Nature Reserve
IUCN Not ReportedNature Reserve
0.21 km² overlap
Marcus Island Marine Protected Area
IUCN Not ReportedMarine Protected Area
0.17 km² overlap
Vondeling Island Provincial Nature Reserve
IUCN Not ReportedNature Reserve
0.15 km² overlap
Computed live · GADM 4.1 × HydroBASINS lev08 × WDPA · cached after first hit.
Species present
4 611 distinct species · 551 323 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 Modder : 28 espèces reliées par 26 interactions GloBI sur 2 types (connectance 5.6%, 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°
17,3°C
Annual rain
368mm
Moisture idx (CMI)
-0,69
Runoff
136mm/an
PET
1 198mm
AET
316mm
Mean slope
1,9°
Water table
476cm
Forest
4%
Crops
49%
Urban
4%
Protected
97%
HydroATLAS BasinATLAS v10 (Linke et al. 2019) · HydroBASINS lev08 (Lehner & Grill 2013)