Abstract:
With the increase in human impacts on the
environment, especially in terms of agricultural intensification
and climate change, erosion processes need to be
assessed and continually monitored. In many countries, but
particularly in developing countries such as South Africa,
standardized methodological frameworks that deliver comparable
results across large areas as a baseline for regional
scale monitoring are absent. Due to limitations of scale at
which techniques can be applied and erosion processes
assessed, this study describes a multi-process and multiscale
approach for soil erosion risk assessment under South
African conditions. The framework includes assessment of
sheet-rill erosion at a national scale based on the principles
and components defined in the Universal Soil Loss Equation;
gully erosion in a large catchment located in the Eastern
Cape Province by integrating 11 important factors into a
GIS; and sediment migration for a research catchment near
Wartburg in KwaZulu-Natal by means of the Soil andWater
Assessment Tool. Three hierarchical levels are presented in
the framework, illustrating the most feasible erosion assessment
techniques and input datasets that are required for
application at a regional scale with proper incorporation of
the most important erosion contributing factors. The methodological
framework is not interpreted as a single assessment
technique but rather as an approach that guides the
selection of appropriate techniques and datasets according to
scale dependency and modelled complexity of the erosion
processes.