Scaling in soil erosion (processes, scale effect and modeling of soil erosion)

This paper was prepared in order to present and asses the methodologies for management and synthesis
of the data obtained from natural and simulated rainfalls, and for data extension to hillslope and
catchment. Thus, the factors affecting the accuracy and variability of the data were firstly pointed out and
the necessity of the scaling was proposed. Scaling is defined as a set of operations to find scale factors to
relate characteristics of one system to corresponding characteristics of another system. Determining of the
scale factors is based on the concepts of dimensional analysis. The soil erosion types and processes were
then mentioned, and the process-based soil erosion models were briefly analyzed which are based on soil
erosion processes and including scale factors. The models are actually data management, synthesis and
extension tolls. Therefore, the practical criteria were mentioned for model choice. Finally, considering
the world experience and the country situation of data and information availability, it was suggested to
use the combination of RUSLE and remote sensing based on a series of field data for long term evaluation
and mapping of soil erosion across the country at hillslope and catchment scales.