coaltech upper olifants river catchment wetland inventory ...

8.2 Mapping
o Small wetlands (of less than half a hectare) cannot be identified on the 1:50 000
aerial photographs and these wetlands are therefore excluded from the wetland
layer.
o The 1:50 000 aerial photographs are slightly skewed to the edges and there may be
some inaccuracy on the exact location of some of the wetlands.
o The aerial photographs were mostly taken in the winter months, thereby affecting the
visibility of the wetlands on the aerial photographs.
o Terrain shadow, cloud shadow and smoke from industries affect the accuracy of the
wetland delineation, since these shadows can be interpreted as wetlands or can
obscure wetlands.
o The aerial photographs are two to three years old and changes may have taken
place, including the expansion of developments over wetland areas. These
developments may include residential, mining, cultivation and industrial
developments.
o The attributes included in the wetland database was based on the aerial photographs
and the available literature, with only limited field verification possible.
o The field verification of some of the wetlands will not replace site specific
assessments.
o The status of the wetlands are the most inaccurate of the attributes, since this
attribute was only based on the aerial photographs and a small amount of field
verification, and a number of threats not visible on an aerial photograph may impact
on the wetland.
o The Red Data species and important species attributes are not site specific, but
based on the wetland type. The status of the wetland was not taken into account.
o Threats included in the wetland database are only those threats visible on the aerial
photographs. Additional threats, not visible on the aerial photographs, may be
present.
Wetland Database for UORC - 93 -