Analisi indiretta dell'entità dell'erosione nel bacino del Fiume Tammaro (Appennino Campano)

Fluvial erosion in the Tammaro River basin (Campanian Apennines)

Abstract

A multiple regression analysis, using network geomorphic parameters drainage density Dd and density of hierarchical anomaly Δa as independent variables, was performed to calculate the value of suspended sediment yield Tu. The calculated values mainly fall into the [72,69 ÷ 1048,77] tons/km²/year class interval, therefore testifying that almost 94 % of the basin area is carachterized by low-medium intensity erosional processes, a phenomenon that can be easily understood considering the nature of the geologic formations outcropping in the Tammaro hydro-graphic basin mainly made of competent, low-erodable rocks. High values of suspended sediment yield, belonging to [826,43 ÷ 3405,90] and [> 3405,90] tons/km²/year class intervals, are found for sub-basins located closer to the valley bottom, on the eastern side of the Tammaro River where more less competent rocks outcrop. Finally, we have evaluated the suspended sediment yield for the whole Tammaro basin as 273 tons/km²/year, an estimate that leads to 216540 tons/year of total amount of suspended eroded sediment in the basin.