Soil Erosion Investigations and Measurements on Flysch in Forested Areas of Central Istria, Croatia

The paper describes methodology, purpose and results of sediment production investigations in central Istria. Investigations are conducted on agricultural surfaces by application of the world famous Wischmjer methodology, on whose basis the USLE erosion estimate method was created in 1978. Cumulative erosion measurements are conducted on forested surfaces of the Abrami research field from investigation tables. Investigation purpose is to determine as precisely as possible sediment production from various (in terms of relief, vegetation, the way of use - cultivation) surfaces, in function of improvement, i.e. a more precise evaluation of particular soil erosion parameters. In pragmatic sense, sediment production calculation within catchment areas is in addition to measurements also carried out by use of parametric methods. Calculation results are particularly significant for designing of accumulations and larger protection regulation systems on watercourses. Precisely sediment production measurement results in central Istria created a bank of measured data, on whose basis the evaluation of particular parameters within parametric methods may be conducted, and particularly the RUSLE method and its derivatives. Thereby an additional reliability of such methods is achieved and eventually even a redefining of its basic mathematical formulations becomes possible.