ИСТИНА

Soil erosion and the related problems, such as water quality issues or decreasing soil productivity, are the main topics affecting the inhabitants of both rural and urban areas especially in semiarid environments. Therefore, in the last decades the attention has been placed on the assessment of soil erosion processes and especially on their quantification. This can also be documented by an increasing number of studies carried out on erosion and by the development and application of erosion models. Nevertheless, gully erosion phenomena have been widely neglected in erosion modelling. This is because the development of erosion models was focused on those regions with an intense agriculture typical of developed countries on the one hand, and because of the spatial and temporal heterogeneity of gully erosion processes on the other hand. This study regards the identification of susceptible areas for gully erosion on the regional scale using a stochastic modelling approach. To quantify the amount of sediments produced by these processes we modelled characteristic gully systems on slope and small catchment scale with a twofold approach applying a stable and a dynamic gully erosion model (Sidorchuk, 1999). The input data for the models is based on high-resolution remote sensing techniques (Mineral mapping, SFM, API) and GIS analyses. The example from KwaZulu-Natal illustrates that areas affected by or susceptible to gully erosion can be identified precisely. Furthermore, it is possible to estimate the amount of soil loss due to gully erosion, which in turn normally is not taken into consideration by the USLE-type models