This paper investigates nearly 30 years of monitoring of sediment fluxes in an instrumented Alpine basin (Rio\ud Cordon, Italy). The collected bedload and suspended sediment transport data allows sediment dynamics to be analyzed\ud at different time scales, ranging from short- (single event) to long-term (three decades). The Rio Cordon\ud monitoring station has been operating since 1986, continuously recording water discharge, bedload and\ud suspended load. At the flood event scale, a good relationshipwas found between peak discharges (Qpeak) andsediment\ud load (bedload and suspended load). The inter-annual sediment yields were analyzed, also assessing the\ud contribution of the single floods to the total sediment budget. The annual suspended load ranges from 10 to\ud 2524 t yr−1, while the bedload varies from 0 to 1543 t yr−1. The higher annual yields were recorded in the\ud years when large floods occurred, highlighting that the sediment budget in the Rio Cordon is strongly controlled\ud by the occurrence of high magnitude events. Investigation of the seasonal suspended load contribution demonstrated\ud that from 1986 to 1993 most fine sediments were transported during the snowmelt/summer seasons,\ud while autumn and snowmelt were the dominant seasons contributing to sediment yield in the periods 1994–\ud 2002 and 2003–2014, respectively. The mean annual sediment yield from 1986 to 2014 is equal to\ud 103 t km−2 yr−1, and overall, bedload accounts for 21% of the total sediment yield. The ratio between the sediment\ud transport and the effective runoff of the events allowed the temporal trends of transport efficiency to be\ud inferred, highlighting the existence of periods characterized by different sediment availability. In particular, despite\ud no significant changes in the hydrological variables (i.e. rainfall), nearly a decade (1994–2002) with high\ud transport efficiency appears to have occurred after an exceptional event (recurrence interval N100 years). This\ud event affected the sediment availability at the basin and channel bed scales, and provided a legacy influencing\ud the sediment dynamics in the basin over the long-term by increasing the transport efficiency for approximately\ud a decade. This work benefits from the long-lasting monitoring program undertaken in the Rio Cordon and is the\ud product of long-term data series. The quasi-unique dataset has provided detailed evidence of sediment dynamics\ud over about three decades in a small Alpine basin, also enabling the effects triggered by an exceptional event to be\ud analyzed

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Suspended sediment transport in streams is an effective indicator of soil erosion at the watershed scale. This process was studied using the data obtained from two continuous monitoring stations installed in Italian watersheds, the Rio Cordon and Torrente Carapelle. The catchments have substantially different climatic, morphological and land use characteristics. The Rio Cordon, a small Alpine watershed, has been monitored since 1986, while in the Torrente Carapelle, a medium-size Mediterranean watershed, the monitoring station has provided data since 2007. Several flood events with suspended sediment transport were isolated in the two catchments, excluding those determined by snowmelt in the Rio Cordon as this process does not affect the Carapelle watershed. Analysis of the events showed different behavior in terms of hysteresis loop trends between water discharge (m3 s-1) and suspended sediment concentration (g l-1) values, as the Rio Cordon confirms clockwise relationships most frequently, while counter-clockwise trends represent the majority of cases for the Carapelle Torrent. The different behavior of the two watersheds was further analyzed by evaluating relationships between the main hydrological parameters related to suspended sediment transport. Runoff controls the total sediment budget in both catchments. In contrast, it was noted that the runoff process does not interfere in the magnitude of the suspended sediment transport in the Rio Cordon catchment, while variations due to the larger size of the catchment area characterize the events in the Carapelle watershed. Lastly, a flow peak threshold that determines the advance or delay of the hydrograph peak with respect to the sedigraph peak was established for the Carapelle Torrent, while it was not reported in the Rio Cordon