Actual water erosion; 1 : 500 000; Potential water erosion (according to W. H. Wischmeier and D. D. Smith); 1 : 1 000 000

On these maps the actual and potential water erosion on the territory of the Slovak Republic are shown. Water erosion at the regional level is normally subject of analyses of the dominant factors and delimitation of the regions, which are potentially or actually threatened by erosion. One of the options of evaluating the water erosion threat is by application of the adjusted mathematical model based on the Universal Soil Loss Equation after W. H. Wischmeier and D. D. Smith. Data accessible at scales 1 : 50 000 - 1 : 500 000 were used. Two aspects were applied to evaluation: Potential water erosion is based on the mutual action of three important factors: erosive effect of precipitations, susceptibility of soil to erosion, and susceptibility of relief to water erosion (determined above all by its inclination). Thus, the produced model characterises the situation of the severest possible threat, which might exist if the surface was not protected by vegetation cover. This model is applied in case of comprehensive evaluation of the threatening landscape natural factors, which determine/limit socio-economic activities in the territory. Actual water erosion is based on the joint action of the above-mentioned three factors and simultaneous land use (landscape structure derived of the CORINE land cover database). The model created in this way expresses the potential water erosion as modified by land use. The model represents one of the source materials in the planning processes with the aim to reevaluate the existing socio-economic activities. With regards to the character of the used data (above all the different degree of generalization) and the applied modified USLE model, the results cannot be presented as concrete values (for instance, soil loss in t.ha-1.year-1). They must be interpreted only as qualitative relative indicators, which make it possible to distinguish the more threatened localities from more stable localities from the viewpoint of action of the water-erosive processes. As the results are also influenced by the quality and character of the data used (derived of the map of medium and small scales), as well as the character of the used empirical mathematical model, they do not fully respect the local differences. (authors)