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Study area
5.2 Study area characteristics
5.2.1 Extent
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The study area stretches across the suburbs of Paarden Eiland, Brooklyn, Salt River and the Harbour. It is crossed and dissected by major rail lines and high ways connecting the City of Cape Town (CoCT) CBD with its surrounds. The sea forms a natural boundary. Koeberg road and the M5 are the eastern boundary. The centre is occupied by PRASA rail yards. The M5 and N1 highways are boundaries for the Salt River canal and the Old Salt River canal.
5.2.2 Topography
With the urbanisation of the area and the establishing of the harbour the topography of the area was modified. The dark turquoise areas being the lowest, show clearly the location of the water bodies. The brown areas are the highest. There is very little slope within the Salt River canal. Higher elevation in Brooklyn and Rugby created the natural boundary for the former Salt River.
The reinforced protected sea wall along the harbour and the coastline up to Milnerton is higher than some of the land behind. It has to be mentioned, that a lidar only shows the water level of water bodies and not the ground level.
5.2.3 Altered topography
During the urban and harbour development substantial parts of the area were filled in to enable development. The harbour development affecting the area the most happened in the 1970-1980’s with the extension of the Ben Schoemann dock, which resulted in the piping of the original Salt River mouth, see photograph across. The salt marsh area was gradually filled in to allow the construction of the rail yards and the northern Metro line to Malmesbury with the Ysterplaat station. It is assumed that the filling was not only done with clean soil, but with any access material left, like from the Salt River Power station.
5.2.4 Wind
Because of the proximity to the sea and its low-lying character the side is exposed to strong winds. The main wind directions in Cape Town being south-easterly for summer and north-westerly for winter. The winter winds have the main influence on the wave action against the coastline.
Study area Vegetation types
Study area
5.2.5 Vegetation
The Salt River was flowing through “a flat slightly undulating landscape covered by tall, evergreen, hard leaved shrubland with abundant grasses and annual herbs” (Mucina, L., Rutherford,M.,2006).
Cape Flats Dune Strandveld, the main vegetation type of the study area, occurs in the Western Cape in four discontinuous regions, the Table Bay coast is one of them. This vegetation group is endangered and under constant threat from development. Remnants of the vegetation type occur in the study area only next to the Zoarvlei wetlands, see diagram 76.
Four other vegetation types of the area are important for the riverine areas, Cape Flats Sand Fynbos, south of Vortreeker road, a Penninsula Shale Renosterveld patch west of that. Not shown in the vegetation layers of the BGIS are the Fynbos Riparian Vegetation on the immediate banks of the river and the Cape Estuarine Salt Marsh vegetation, see diagram75.
Fynbos Riparian Vegetation is part of the alluvial vegetation and occurs in the Western Cape near sea level to
1300m altitude. “Narrow, flat or slightly sloping alluvial flats supporting a complex of reed beds, dominated by tall palmiet and restios, low shrubland with moisture loving species and tall riparian thickets in places. This vegetation is in many patches well protected, but prone to infestation by alien woody plants” (Mucina, L., Rutherford,M.,2006). Fynbos Riparian Vegetation is completely lost in the study area through the modification of the river and the construction of the canal. It plays an important role in the sediment transport, in collecting sediments during floods. “The streams are mainly fed during the winter rainfall season and later through seeps carrying acidic water rich in organic compounds (tannins) and with a characteristic brownish color. Large streams carry water all year around, while smaller streams can turn into a series of disconnected pools in the upper reaches in summer. Many trees and shrubs are adapted to uprooting or heavy damage by spates. The heavy erosion also results in a soil-poor substrate and plant cover is often very patchy, located in some small depressions with some soil development or between
Study area
boulders”(Mucina, L., Rutherford, M., 2006).
Cape Estuarine Salt Marshes must have been the main vegetation type for the Salt River estuary. It occurs on the Atlantic coast at estuaries and salt marsh plains. “Estuarine Flats and systems of low riverine terraces supporting complexes of low herb land and shrublands dominated by succulent chenopods and flood tolerant halophytes, salt marsh meadows dominated by rushes and sedges and temporary submerged sea-meadows at the lower boundary of the tidal zone”(Mucina, L., Rutherford, M., 2006).
On the Diep River mouth at the Milnerton lagoon exists a small remnant of this vegetation type, see diagram76.
5.2.6 Public Open Space
Public Open Space zoning in the study area is mostly associated with the waterbodies along the former river corridor, now next to the Zoarvlei wetland and Salt River canal north of the N1, see diagram 77.. A substantial piece between the canal and the Old canal lies on the rail yard, which can be associated with the former Salt marsh in this
Study area
area. Another open space zoning sits isolated between the Marine Drive and the rail tracks along the coast, parts of this space is used for the Milnerton market every weekend.
Parks and sports facilities are mostly situated within the residential areas of Rugby and Brooklyn. A single park exists in Paarden Eiland. The beach along the coast line can only be accessed from the north at the Diep river mouth, the area south of the Salt River mouth belongs to the harbour and can’t be accessed by the public.
