KEURBOOMS RIVER: Topography, geology and soils

eWISA Home  |  KEURBOOMS: MAIN INDEX |  ALPHABETICAL LIST OF RIVERS
                             
 

Map of the KEURBOOMS River

E-mail us                    
TOPOGRAPHY
One of the major features of the region is the Jurassic, west-east trending Cape Fold Belt and in particular the southern orographic line, which includes the Outeniqua, Langkloof and Tsitsikamma Mountains .  On the seaward side of this mountain range, the inland plateau becomes a lake system valley, reaching the sea through the Keurbooms Estuary.  This valley is flanked by a coastal plateau, which includes the Aeolian sand dunes occurring between Robberg and Keurboomstrand.  The coastline in Formosa Bay was shaped into a crenulated bay by waves diffracted around Robberg (Ref. 1).
The southern boundary of the Keurbooms catchment is situated on the coast. The mountains to the north are rugged and barely accessible (Ref. 12).  The main Outeniqua mountain range, elevation >1200 m, runs east-west and the south-facing slopes are significantly moister than the north-facing slopes. The coastal section includes a broad elevated coastal plateau (150–250 m) with deeply incised river valleys.
    GEOLOGY                                    
The drainage basin of the Keurbooms River is predominantly underlain by orthoquartzite of the Table Mountain Group (Ref. 2).
    SOILS                                    
The Table Mountain Group weathers to acid, well-drained soil.  Fluvial sand forms only a small part of the estuarine sediment input (Ref. 2). 
Apart from the presence of swelling clays in certain areas, large areas are covered by sandy soil and drift sand (Ref. 9).
  References                                      

Ref 1:  Duvenhage, I.R. and Morant, P.D. (1984). Estuaries of the Cape Part II: Synopses of available information on individual systems.  Report No. 31 Keurbooms/Bitou System (CMS 19) Piesang (CMS18).  CSIR Research Report 430. 64pp.

Ref 2:  Reddering, J.S.V. (1981).  The sedimentology of the Keurbooms Estuary.  M.Sc. thesis. University of Port Elizabeth .  Geology Department

Ref 9:      South African (Republic).  (1983).  Department of Constitutional Development and Planning. Knysna – Wilderness – Plettenberg Bay Guide Plan.  99pp.
  Useful links