Geoscience Reference
In-Depth Information
Figure 12.7 (a) Location of the Klip River catchment in eastern South Africa, also showing the location of the neighbouring
Venterspruit and Schoonspruit catchments (from Tooth et al. , 2004). (b) Schematic illustration of the factors promoting
meandering and floodplain development in sandstone/shale valleys upstream of resistant dolerite sills or dykes (after Tooth
et al. , 2002a). (c) Longitudinal profiles of the Klip River, Venterspruit and Schoonspruit (constructed from contour crossings
on 1 : 50 000 topographic maps), showing how channel-bed gradients are lower upstream and downstream of major dolerite
sills or dykes (from Tooth et al. , 2004). (d) Planforms of three neighbouring rivers with different degrees of downstream
dolerite control, illustrating the contrasting channel sinuosities and the differences in the number of oxbows, abandoned
channels and dongas: Klip River (intact dolerite sill at lower end of study reach), Schoonspruit (partially breached dolerite
sill at lower end of study reach), Venterspruit (fully breached dolerite sill at lower end of study reach). Note the different
scale for the Klip (from Tooth et al. , 2004). Parts (a), (c) and (d) reproduced with kind permission of Elsevier.
between alluvial and bedrock processes and that the dryland climatic influences are relatively muted. Geologically
controlled, long-term cycles of wetland formation and destruction are a key natural element of these landscapes, but
in some areas poor land management and artificial drainage schemes have also contributed to wetland desiccation
and donga erosion.
Search WWH ::




Custom Search