GREATFISHNEW RIVER: Topography, geology and soils

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

Map of the GREATFISHNEW River

E-mail us                    
TOPOGRAPHY
The  area is dominated by the arid Great Karoo interior. This area is bounded in the north by the mountain ranges of the interior plateau and in the south by the higher rainfall coastal catchments. The topography is relatively flat and the basin soils are naturally highly erodible. (Ref 1)

The upper parts of the Great Fish catchment, with a total area of about 30 000 km2, have numerous small, and usually dry, tributaries that originate along the edge of the interior plateau. The Tarka River tributary rises in the northern slopes of the Winterberg Mountains, while the Little Fish River tributary drains the arid area to the southwest of Cradock. The Koonap River rises on the southern slopes of the Winterberg and flows through mountainous terrain to join the lower reaches of the Fish River. The Kat River catchment, with its headwaters in the vicinity of Seymour, has a fairly wide main valley. Only minor tributaries join the Great Fish River downstream of its confluence with the Kat River. The Great Fish River then flows for a further 100 km through deeply incised meanders in hilly terrain to its estuary 25 km east of Port Alfred. (Ref 1)

    GEOLOGY                                    
In the southern coastal belt folded sedimentary rocks of the Cape Supergroup (Table Mountain, Bokkeveld and Witteberg Groups) and lower Karoo Supergroup (Dwyka and Ecca Groups) are the dominant bedrock units. (Ref 1)
    SOILS                                    
Moderately deep to deep clayey loams are found in the undulating terrain of the coast in the south-east and in the upper portion of the Fish River basin.  (Ref 1)
  References                                      

Ref 1:  Department of Water Affairs and Forestry, South Africa. 2005. Fish to Tsitsikamma Water Management Area: Fish to Sundays Internal Strategic Perspective. Prepared by Ninham Shand in association with Umvoto Africa, on behalf of the Directorate National Water Resource Planning.DWAF Report no. P WMA 15/000/00/0405.
  Useful links