Investigating sediment sources within a small catchment in southern Italy.

Soi! erosion is a serious problem in many areas of Italy, particularlrin the south, where rates of soil loss can exceed 100-150 t ha-I year' .Although the impact of these high rates of soi! loss has traditionally beenassessed in terms of soil degradation, off-site problems related to more generaIenvironmental degradation are attracting increasing attention. In order toimplement meaningfu1 sediment control strategies, it is necessary to establishboth the nature and the location of the main sediment sources within acatchment. Sediment fmgerprinting has been increasingly identified as aneffective approach for assembling infonnation on suspended sediment sources.The study reported uses source fingerprinting techniques, based primarily onradiometric fmgerprints (137Cs and unsupported 21Opb) to establish the primarysediment sources within a small forested catchment (1.38 ha) 10cated inCalabria, southem Italy, where independent information on the spatial pattemof surface erosion rates was available from 137Cs measurements. The sourcetracing investigation showed that most sediment originates from the southfacingslopes, where the tree cover is discontinuous, emphasizing the importanceof vegetation cover in influencing sediment mobilization from the studyarea. These findings are consistent with the previous work involving 137Csmeasurements, which again identified the south-facing slopes with discontinuoustree cover as the areas with the highest rates of soil loss.