Home Wetlands in South Africa Ramsar Sites Definition of a Wetland
|Velorevlei is situated on the west coast of South Africa, about 25km from the small coastal town of Lamberts Bay, in an area where the cold Atlantic Ocean contrasts beautifully with the dry and rocky interior. Verlorenvlei is located in the Western Cape (32º24’S 018º26’E). With and area of 1 500 ha, it is one of the largest lakes and one of the country’s few coastal freshwater lakes. The catchment of the lake is about 1 890 km2 in extent (Ref. 5). A small estuary connects the lake to the sea and marshlands are present along the main river which enters the lake (Ref. 1). The Verlorenvlei stretches between the West Coast villages of Elandsbaai and Redelinghuys. The Verlorenvlei wetland has been classified as comprising both fresh oligotrophic lake (Type 19) and marshland and reedswamp (Type 26).|
|Area: 1500 ha ( http://www.ramsar.org/index_list.htm )|
|Land uses Top|
||Natural: It is proclaimed a Ramsar site (No. 525). The Lake itself is owned by the state (Ref. 1).|
|Agricultural: The surrounding area is privately owned and farm boundaries extend to the 50 year flood line. Fields have been established along part of the lake margins and extend below high water marks in places. Extensive ploughing has occurred in the surrounding area particularly on the hills south of Verlorenvlei. The greater part of the Verlorenvlei wetlands is used as natural veld grazing for sheep and cattle and water is pumped for irrigation purposes and the marshland is used for cattle grazing (Ref. 1).|
|Industrial: Important fishing grounds are found along the coast and four small fish processing factories have been built along the coast at Baboon Point. These factories are mostly concerned with the crayfish industry although a small amount of fish processing does occur (Ref. 1).|
|Urban: A small village, Eland's Bay, lies along the coast near the mouth of the estuary (Ref. 1).|
|Algae: Large masses of filamentous green algae, including Chaetmorpha and Cladophora, are common in the channel, particularly between the railway bridge and the lower causeway, where the water is often stagnant and hyper saline (Ref. 6).|
|Aquatic vegetation: Extensive beds of emergent aquatic macrophytes occur along the margins of the lake with Phragmites australis, Typha latifolia and sedges as dominants. Downstream of Redelinghuys there are fairly wide and open wetlands with patches of mixed sedges and reed communities along the course of the Verlorenvlei River over a distance of 11km. Dense reedbeds are present in the upper part of the lake. Myriophyllum spicatum, a submerged macrophyte, dominates large areas of the lake where the water is about 2m deep. The water lily, (Nymphaea capensis), a species which is becoming rare in South Africa due to destruction of wetlands, occurs in small numbers (Ref. 1).|
The Verlorenvlei wetland is of significant botanical
importance, because of its position at the transition between the
karroid and fynbos vegetation types. The region therefore, has a high
diversity typical of an ecotone area (Ref. 1).
site also supports notable rare plant species, such as Ferraria
foliosa, F. densepunctulata, Cerycium venom (presumed extinct) and
Cullumia floccosa (Ref. 1).
Birds: In 1976, 934 and 1 371 waders were recorded respectively during two surveys in the lower reaches of Verlorenvlei (Ref. 7). Of these numbers, 95% were migrants. In a later survey (1983) of the whole Verlorenvlei, 3 655 waders were reported, of which 2 928 were migrants and 727 residents. This same survey yielded a total of 6 829 birds of 60 species in the environs of Verlorenvlei (Ref. 1). The vlei also provides feeding, nesting and roosting sites for 200 species of birds in the surrounding area. It is an important moulting area for Egyptian geese (Alopochen aegyptiaccus) and other waterfowl (Ref. 1).
seen at Verlorenvlei include herons, egrets, ibises, spoonbills and
flamingos. The presence of glossy ibises and African spoonbills is
important, since these species are uncommon in the south-western Cape
(Ref. 8). Flamingos appear at Verlorenvlei when other vleis, such as
Rocher Pan (35km south) and Wadrifsoutpan (13km north) dry up.
Flamingos are listed in the South African Red Data Book as requiring
conservation (Brooke 1984).
Red Data Book species include the little bittern and the Caspian tern.
The area is possibly also an important moulting ground and summer
refuge for ducks, with 600 Cape shoveller and 1 200 yellow-billed duck
being observed in May 1979 (Ref. 1). In addition, Verlorenvlei is a
type locality for several species of birds, including the white-backed
duck (Thalassomis leuconotus) (Ref.
to 150 great white pelicans were counted by the Fitz Patrick Institute
in 1976, representing 26% of the total south-western Cape population
(Ref. 8). On 23 March 1982, 212 pelicans were counted. The great white
pelican is rated as rare in South Africa, and therefore in need of
special protection (Ref. 9).
vlei is also an important feeding area for the rare white pelican (Peleanus
Little information exists on
mammal populations at Verlorenvlei. Archaeological and historical
evidence suggest that larger mammals were present in abundance in the
past, whereas they are non-existent today.
A survey by Stuart (1981) indicates the presence of the 12
carnivore species and 11 other mammal species in the vicinity.
|Topography and geology Top|
The Verlorenvlei Wetlands is between 1 and 5 m above mean sea
catchment is about 87km long in a north-west/south-east direction and
up to 43km wide. Its surface area is estimated (Ref. 5) to be 1 890km2,
or 198 000 ha.
catchment is bounded by the Swartberg and Olifantsrivierberge in the
east and by the Piketberg in the south, and includes the Eendekuil
basin, a low-lying area lying between the Olifantsrivierberge and the
Piketberg. The Verlorenvlei River and its tributaries drain the entire
Eendekuil basin, the Table Mountain Group mountains around
Paleisheuwel, the northern outliers of Piketberg, the extensive flats
of Tertiary to Recent sands between Het Kruis and Redelinghuys and the
5km strip of low Table Mountain Group hills and sand flats on either
side of the lake which contribute seepage (Ref. 1).
The Malmesbury Group
(Proterozoic) has been subdivided on purely lithological grounds into
three groups, calcareous, quartzose and phyllite with greywacke. The
calcareous group comprises pure limestone, dolomitic limestone and
dolomite. Carbonaceous patches and calcareous rocks grade into
showing a high degree of lithological similarity to the Klipheuwel
beds of the type area are found in small occurrences along
Verlorenvlei. No angular inconformity is visible between them and the
Table Mountain Group but their regional relationships clearly show the
presence of an inconformity. Rogers named these rocks Ibiqua Beds,
which implies a correlation with the Nama System, for which there is
no proof available yet (Ref. 2).
(Proterozoic) comprises the following: purple to red-dish brown sandy
micaceous shale which is mostly poorly-bedded and grades into
mudstone; alternating beds of sandstone, shaly sandstone and sandy
shale with colours ranging from buff to purple and red; white and
brightly coloured sandstone and grit with minor conglomerate and shale
layers. The arencaeous strata are commonly cross-bedded, quite often
feldspathic, and much softer than the Table Mountain Group sandstone.
The maximum thickness exposed on the eastern boundary of this area
amounts to about 375m.
to slightly-reddish sandy soil originated mainly from the underlying
unconsolidated to partly-consolidated sand and clay, and to a lesser
extent from the Table Mountain Group, the coastal dunes, and fluviatile deposits of
past and present drainage systems.
phenomenon of 'heuweltjies' occurs
on the Verlorenvlei area, and is easily detectable both on the ground
and in aerial photographs. Different theories have been propounded as
to their origins. They include calcareous layers and higher clay
content in the soil deriving from old termitaria. The activity of mole
rats may also contribute to the formation of 'heuweltjies'
Harmse (Ref. 3), in his Schematic Soil Map of Southern Africa (1978),
classifies the Verlorenvlei area as a zone of littoral sands which are
arenosols, or of aeolian origin. He points out that the salient
feature of such soils is their low reserve of weatherable minerals,
and the low silt/clay ratio. Taylor (1987) describes these coastal
lowlands as consisting of sands and conglomerates of Tertiary to
Recent origins. He comments on their low water-retaining capacity,
being either acid and relatively infertile or, nearer the coast,
alkaline with a distinct horizon of lime accumulation. The
'heuweltjies' or hillocks have higher clay content than the
surrounding soils (Ref. 4).
general Verlorenvlei area is characterized by type a fine sandy soil,
in which the dominant types are Fernwood and Mkambathi; the
sub-dominant Hopefield; and the rare Langebaan, Sandveld and
Sonneblom. On the southern bank, extending from Elandsbaai to
Redelinghuys, are isolated sections classified as rock and
Elandsfontyn Formation beneath, being peaty clay and sand;
the controversial Saldanha Formation;
the Varswater Formation, being conglomeratic phosphorite;
the Bredasdorp Formation (on top), with three aeolianite
phases, the third being unconsolidated (Ref. 2).
and debris are found in numerous places at the foot of cliffs and
along small streams that flow down hillsides after heavy downpours.
The river is flanked by strips of alluvium, part of it being black and
rich in plant material. Several patches of drift sand and bare dunes
away from the coast originated mostly from mismanagement of the veld.
A large dune field occurs to the north of the river mouth and the town
of Elandsbaai .
|Hydrology and geohydrology Top|
entire channel is very shallow (about 0,5m deep), tending to inhibit
free water circulation. A natural obstruction at the mouth is a rocky
sill topped by a sand bar, above the normal reach of high tides. The
sand-topping is formed by a south going longshore current, in
combination with frequent onshore winds.
two types of wave-induced inshore currents, one north going and the
other southward, appear to keep a hydraulic and sedimentological
near-equilibrium at the beach. Consequently, provided the balance
(including source of sand) is not disturbed, a sufficient sand supply
from the beach will always tend to cober the rocky barrier at the
mouth, to such an extent that the mouth has little chance to remain
open for any appreciable length of time after breaching.
Verlorenvlei has a mild,
Mediterranean climate, with predominantly sunny days throughout the
Verlorenvlei has an average
annual rainfall of 275mm of which an average of 70% falls in the
winter half-year (April to September).
Single very rare heavy showers can account for as much as the
normal annual precipitation. Hail is seldom reported in this region
Temperature: The highest average maximum temperature (24, 42 °C) occurs in January and the lowest average minimum temperature (8, 7 °C) occurs in July (Ref. 1).
pressure in the Verlorenvlei area has been concentrated along the
coastline, in the vicinity of Elands Bay. The pressure is beginning to
increase in the form of applications for township extensions (Ref.
10). The coastal environs attract weekend and holiday visitors,
particularly in the summer, causing short term, seasonal increases in
the demand for facilities.
sources of threats in the future include (Ref. 1):
South African Wetlands Conservation Programme: Verlorenvlei.
Information sheet for
the site designated to the List of Wetlands of International
Importance in terms of the Convention on Wetlands of International
Importance especially as Waterfowl Habitat. http://www.ngo.grida.no/soesa/nsoer/resource/wetland/verlorenvlei.htm
|Ref 2. Rogers,
J. (1980). First report on the
Cenozoic sediments between Cape Town and Elands Bay. Pretoria Rep.
Geol. Surv. S. Afr. 165:1-64.
|Ref 3. Harmse, HJ, Von M. (1978). Schematic soil map of southern Africa south of latitude 16o30'S. In: Werger, M.J.A. Biogeography and ecology of Southern Africa. Junk, The Hague. pp: 73–75.|
|Ref 4. Taylor, H.C., (1978): Capensis, in Werger, M.J.A. (ed), Biogeography and Ecology of Southern Africa, Junk, The Hague, 171-229.|
|Ref 5. Noble, RG. and Hemens, J. (1978). Inland water ecosystems in South Africa - a review of research needs. CSIR, Pretoria, South Africa.|
|Ref 6. Robertson, HN. (1980). An assessment of the utility of Verlorenvlei water. University of Cape Town.|
|Ref 7. Summers, R. W., Pringle, J. S., and Cooper, J. (1976). The status of coastal waders in the south-western Cape, South Africa. Western Cape Study Group. 162p.|
|Ref 8. Cooper, J. (1976). The ornithological importance of Verlorenvlei and its value as a nature reserve. Unpublished memorandum. University of Cape Town, Percy Fitz-Patrick Institute of African Ornithology.|
|Ref 9. Brooke, R.K. (1984). South African Red Data Book - Birds. S. Afr. Nat. Sci. Prog. Report. 97: 1 - 123.|
|Ref 10. Heinecken, T.J.E. and Badenhorst, P. (1985). Elandsbaai extensions 2 and 3. Unpublished report. Stellenbosch, National Research Institute for Oceanology, CSIR.|
|Useful links Top|
|Ramsar List and Facts|
|South African Wetlands Conservation Programme: Verlorenvlei|
|Information Sheet on Ramsar Wetlands (RIS).|