Extreme sheet and rill erosion on agricultural slopes in the flysch Polish Carpathians

Sheet and rill erosion plays an important role in the transformation of agricultural slopes in the Carpathians. It is an episodic process of short duration which can take place both in the winter and summer hydrological half-years as a result of meteorological short-term and high-intensity events like short downpours, intense continuous rainfall and rapid thaws. The climate of the Carpathians is characterized by the variability of its parameters caused by the growing height of the mountain belts from the north to the south as well as by the considerable latitudinal extent of the mountain range. The summer season is crucial to annual precipitation totals. Maximum daily precipitation totals are the result of intense continuous rainfall (mainly in June and Juty) and short local downpours (mainly in May). In the flysch Polish Carpathians the role of sheet and rill erosion on agricultural slopes is different in areas characterized by mountain relief (Beskidy Mountains) and foothill relief, because the two regions have different water circulation patterns and weathered material displacement patterns. Another crucial factor that helps account for the differences in the effectiveness of sheet and rill erosion is vegetation cover. The lack of sufficiently long measurement series or diversification between regions of the Carpathians makes it difficult to determine the frequency of extreme sheet and rill erosion and their recurrence, which means it is not possible to define the quantitative criteria for establishing extreme sheet and rill erosion processes for the whole area of the Polish Carpathians. The aim of this paper is to examine the criteria on the basis of which extreme sheet and rill erosion on agricultural slopes has so far been determined as well as the effects and role of the process in the transformation of the slopes