Abstract:
Wetland delineation is commonly based on terrain unit, soil form, soil wetness and vegetation
indicators. These and the shallow groundwater or proximate surface water are often absent in many
ephemeral inland South African areas due to, for instance, prolonged dry periods (seasons to years) which
mask these indicators, as well as disruption of surface materials due to construction, agricultural activities and
field fires. Furthermore, many “wetlands” in South Africa comply with the four indicators, but the notable
absent requirement for wetlands are missing, namely the shallow groundwater table, as many of these
systems form in hillslope seeps, catenas or from perched water tables. A 200 m long excavation through one
such a system is being studied in Midrand (Gauteng, South Africa). The site is underlain by Lanseria Gneiss and
is waterlogged after long and intense periods of intense rainfall. Frequent downslope soil profiling, horizonspecific
laboratory analyses for grading and Atterberg Limits, X-Ray Diffraction and X-Ray Fluorescensce
Spectroscopy data are interpreted together with soil percolation tests to generate a conceptual model of the
system. The results are discussed in terms of the need to consider these temporary systems that do not have
a shallow groundwater table and that are not in direct contact with surface drainage features as a possible
special type of wetlands, notably in arid regions where they play a very important role in biodiversity and
should, therefore, be protected.
