Integrated approach to the evaluation of denudation rates in an experimental catchment of the Northern Italian Apennines

This paper presents the main results of a multidisciplinary study, aimed at the quantitative direct and indirect evaluation of erosion rates. The investigation was carried out in the small semi-agricultural Centonara catchment, in the Northern Italian Apennines, within the Mediterranean climate region. The Centonara catchment is heterogeneous from the point of view of lithology, geology, slope angle, vegetation and land cover. 20 % of the entire area is occupied by badlands (calanchi), characterized by bare soil and slope gradient over 40 % and affected by rapid morphogenesis mainly due to rill and gully erosion. For this study, 21-years monitoring data of sediment rate were compared with the results of the grid analysis of the ‘‘Tu Denudation index’’. Direct monitoring of sediment transport showed the high variability of rainfall, flow and erosion rates. Moreover, during a single year a few very intense rainfall events determine peak flow of the Centonara stream and exceptional sediment transport, influencing the overall erosion rates. The zonation of the estimated erosion rates highlighted that more than 40 % of the sediment rate derived from the calanchi badlands, while the arable lands and the areas occupied by natural vegetation (both herbaceous and woody) contributed only minimally to the generation of surface runoff and erosion.