Digital soil mapping for hydropedological purposes of the Cathedral Peak research catchments, South Africa

Conventional soil mapping in montane environments is often a difficult and laborious task given access difficulties, the topography of the environment and the time required to conduct the field investigation. Utilising a remote sensing tool, such as the Arc Soil Inference Engine (ArcSIE) to map soils in these locations can add valuable information for land management. The ArcSIE tool was utilised in the Cathedral Peak research catchments, in KwaZulu-Natal, South Africa with the aim of creating an understanding of the hydropedological behaviour of the soils of three research catchments. A rule-based approach was first undertaken, followed by a case-based validation. A fuzzy membership map of each soil group was produced which integrated all inputs. The overall Kappa coefficient for Cathedral Peak-III is 0.57, for Cathedral Peak-VI is 0.59, and for Cathedral Peak-IX is 0.74. The hydropedological soil group maps achieved an appropriate representation of the complex nature of the soil-landscape relationship, with changes between one soil group and the next being gradual and continuous. Accuracies and inaccuracies within the fuzzy-membership maps can be quantified, allowing for a confidence rating in the use of these maps. These maps can therefore be used in further applications in water and land management for the area.