|
|
eWISA
Home |
EERSTE:
MAIN INDEX |
ALPHABETICAL
LIST OF RIVERS |
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
Map
of the EERSTE River |
|
E-mail
us |
|
|
|
|
|
|
|
|
|
|
|
|
TOPOGRAPHY
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
The
Eerste
River
rises in Dwarsberg at the head of Jonkershoek near Stellenbosch, covers
the eastern part of the
Cape
Flats
and stretches from the west of the
Hottentots
Holland
Mountains
to the south of the Tygerberg(origin Kuils River) (Ref 1)
|
|
|
|
|
 |
|
 |
|
 |
|
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
GEOLOGY
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
The Eerste River rises on Dwarsberg and
various tributaries arise on the adjoining Jonkershoek, Stellenboschberg
and Simonsberg Mountains which consist mainly of folded Quartzitic Table
Mountain Sandstone. (Ref 1)
|
|
|
Much of the catchment area consists of
undulating hills with fertile soils overlying Cape Granite and
Malmesbury Shale. The lower reaches of the Eerste River and Kuils
River lie inthe low-lying coastal plain on aeolian sands.
(Ref 1)
|
|
|
Rocks of the Malmesbury Group include shale,
greywacke and siltstone, are Precambrian and about 800 million years
old.
|
|
|
Batholiths and plutons of Cape Granite
penetrated this area during the tectonic period of formation of the
Malmesbury group rocks. Most of the granite has a coarse
porphyritic texture but adjoining the contacts with Malmesbury
(Ref 1)
|
|
|
The Klipheuwel Formation including
conglomerates and sandstone layers overlies the older Malmesbury rocks
and Cape Granite in the Klapmuts area and is considered to be of late
Pre-Cambrian age. (Ref 1)
|
|
|
Dolerite intrusions are present in several
places and are of uncertain age as they penetrate Malmesbury, Cape
Granite and Cape Supergroup rocks while some are cut off and covered by
Cape Supergroup sediments and appear only in hte older Pre-Cambrian
basement rocks. (Ref 1)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
SOILS
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
During the quartenary period sediments
including sand, silt, clay and mud accumulated in the drowned coastal
area. Plant material collected in the vlei areas and led to the
development of peat layers between sand layers. (Ref 1)
|
|
|
The presence of an excess of calcium
carbonate in the form of shell fragments led to the formation of
calcrete layers.
|
|
|
Towards the interior the sands are darker
grey or reddish-brown and scattered ferricrete and silicrete layers are
present. (Ref 1)
|
|
|
The catchment of the upper reaches of both
the Kuils and the Bottelary Rivers are underlain by rocks of the
Malmesbury Group. These are metamorphic sediments, consisting of
quartzites, phyllite, greywacke and shales of Precambrian age and are
coverd by recent thin deposits of loam. (Ref 1)
|
|
|
Below the confluence of the above two rivers
the geology is characterised by considerable depths of tertiary and
recent deposits of loose sand and dune formations underlain by extensive
clay lenses. Scattered deposits of gravel, sandstones and
conglomerates together with irregular development of silicrete and
calcrete occur throughout the area. (Ninham Shand, 1979.)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
References |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Ref 1: Estuaries of the Cape
REPORT NO. 16 EERSTE (CSW) CSIR RESEARCH REPORT 415
|
| |
Useful
links |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
