The topography is rugged and deeply folded. A steep outer ring of high mountains forms the water shed, with an inner area of subdued relief. These plateaus at 650-900m ASL and represent old mature land surfaces (African Land Surface – ALS -120 mill. Yrs. ago). Similar features can be seen in the Kromme River valley. The internal floodplain is divided into large alluvial basins by erosion-resistant, higher lying ground (Map). The altitude of the valley floor: 300 – 700m asl., the lowest point in the catchment, being the confluence with the Kouga River at < 160 m above sea level (asl). Scholtzberg (1626 m) and Smutsberg (1758 m) are the highest points on the northern and southern watersheds respectively. Slope gradient of mountains 30 – 40%, 60% in some areas. Only about 30% of the area has a slope of less then 30%. The slope dictates a lower energy capacity than the rainfall intensity would normally indicate. On the steep slopes the soils are shallow and frequent slope failures are visible throughout the entire length of the valley (Rust and Illenberger 1989). (Ref 2)

• Peninsula
• Cedarberg
• Goudini
• Skurweberg
• Baviaanskloof formations. (Ref 3)

The dominant lithology of the Baviaanskloof is Table Mountain Sandstone. Bokkeveld shales appear to be restricted to two areas that border the Baviaanskloof – Kouga (B – K) fault. The larger of the two areas is confined by two transverse faults which terminate south of the B – K fracture. The western fault terminates on the farm Beaco’s Nek in he center of the valley, while the one in the east terminates on Joachim’s Kraal. A smaller area of Bokkeveld shales is centered on the farm Uitslag to the west of Beaco's Nek. Exposures of Enon conglomerate (Uitenhage Group) outcrop intermittently immediately adjacent to the B – K fault from Nieuwekloof to Kruisrivier. The B – K fault is largely coincident with the main valley and no doubt has had a strong impact on the evolution of the drainage basin. Vertical movement along the fault may explain the presence of the deeply incised slot canyons in the northern fault block. Planation surfaces have been preserved on the interfluves on both the south- and north-facing valley sides.(Ref 2)

Deep soils occur only on the flatter areas of the Baviaanskloof on the African Land Surface plateaus and valley floor. These are the areas where wetlands can be expected. However the soils are of the stratified alluvial Dundee type, which have high drainage with some clay in places (detailed analysis only from Sewefonteine). This factor alone mit igates against formation of wetlands other than along the riverbanks. (Ref 4)

Ref 2:  The Baviaanskloof River