|
|
eWISA
Home |
KLIP:
MAIN INDEX |
ALPHABETICAL
LIST OF RIVERS |
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
Map
of the KLIP River |
|
E-mail
us |
|
|
|
|
|
|
|
|
|
|
|
|
TOPOGRAPHY
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
The
Klip
River
originates in the
Witwatersrand
range of hills, which runs across the
Witwatersrand
urban complex in an east-west alignment (Krugersdorp to Springs). This
ridge also forms the drainage border between the larger Vaal River
Catchment (to the
south)
and the
Crocodile River
catchment (to the north). (Ref 1)
|
|
|
The altitute of the study area
ranged from approximately 1 800m above mean sea level (a.m.s.l.) at the
source, to 1
420m a.m.s.l. at the confluence with the
Vaal
River
.
(Ref 1)
|
|
|
The natural topography of the upper
catchment is largely modified by mine dumps. Steep
rocky ridges are found in the upper
Klip
River
catchment.
|
|
|
Topographically, the lower
Klip
River
area is fairly featureless as the flood plain widens
and as the catchment area narrows towards the confluence with the
Vaal
River
(Otto, 1996;
DWAF, 1999). (Ref 1)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
GEOLOGY
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
The general geology of especially the upper
reaches of the
Klip
River
catchment is
complex. It comprises a succession of formations dipping steeply towards
the south and
striking in a roughly east-west direction. The Basement Complex granites
in the north are
overlain
by the Hospital Hill Sequence of interbedded quartzites and shales. (Ref
1)
|
|
|
In turn, they
are again covered by the Witwatersrand Sequence shales, quartzites and
conglomerates
containing the gold-bearing reefs. The Ventersdorp Supergroup lavas of
the
Klipriviersberg follow to the south and are overlain by the younger
Malmani Dolomites,
with the Black Reef Formation quartzites occurring on the interface. All
of the above
formations
may be intruded by diabase dykes. (Ref 1)
|
|
|
Fresh, hard rock dolomite is
encountered at
depths ranging from 0 to 50 meters below the ground level throughout
much of the
catchment. The level and chemistry of the groundwater affects the nature
and weathering
of these rocks. This can lead to the creation of sub-surface cavities
which can, under
certain conditions, develop as surface subsidence or appear as sinkholes
(DWAF, 1999).
(Ref
1)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
SOILS
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
In the sub-humid climatic zone (annual
rainfall 500mm to 750mm such as in
Klip
River
catchment) the underlying geology has been subjected to differential
weathering. This
gave rise to residual soils, which may vary significantly over short
horizontal distances.
(Ref 1)
|
|
|
The soil profile may range from large
rock pinnacles to either soft or firm clayey silts of
low permeability, and which are often volumetrically unstable. Soils in
the upper reaches
are predominantly sandy loams and those of the lower reaches
predominantly clayey
loams. Both soil types are derived mainly from the weathering of
dolomites and sandstone
(DWAF, 1999).
(Ref 1)
|
|
|
Differential weathering has also
resulted in the formation of large hard rock corestones in a
matrix of completely decomposed softer material. Underlying rocks are
KLIPeted by
either a thin horizon of gravity transported, gravelly colluvium, or in
the vicinity of
watercourses, by clayey water transported alluvium. These transported
soils are seldom
more than two meters thick. The alluvial clays are generally highly
potentially expansive.
The degree of weathering generally reduces with depth, the reddish
clayey material
grading into firm, brownish silts, which in turn change to stiff or very
stiff, highly joined
silts and soft rocks (Otto, 1996; DWAF, 1999).
(Ref 1)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
References |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Ref 1:
etd.rau.ac.za/theses/available/etd-05102005-113926/restricted/CHAPTER2Catchment_.pdf
|
| |
Useful
links |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|