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| Titel |
Suspended sediment transport during rainfall events in the Rio Cordon
(Italy). Analysis of the last decade. |
| VerfasserIn |
Adriana García-Rama, Riccardo Rainato, Mario Aristide Lenzi |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250127600
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| Publikation (Nr.) |
 EGU/EGU2016-7494.pdf |
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| Zusammenfassung |
| This work shows the results of 11 years of measurements carried out in the Rio Cordon
catchment, a small watershed located in the Eastern Italian Alps. A monitoring
station installed in 1986 is continuously measuring several hydrological parameters.
Hourly values of water discharge and water turbidity (or 5 min interval during flood
events) were recorded throughout the whole study period. Several flood events
induced by rainfall and presenting suspended sediment transport were isolated, and
variations of the hydrograph and sedigraph during these events were studied. The return
interval of the water discharge showed always values under 3 years during the studied
period. Consequently, only ordinary floods are analyzed in this work. The hysteresis
relationship between suspended sediment concentration SSC and water discharge Q
was established for each event. Runoff volumes and suspended sediment loads
were calculated for every season of the study period, in order to assess the fraction
of the suspended load produced by floods within each season. The results show
that clockwise loop is the most frequent relationship between Q and SSC in the
Rio Cordon basin. This can be explained by a morrenic belt located in the upper
part of the catchment. This belt creates a strong disconnectivity and blocks the
sediments originated upstream. Consequently, only the sources which are close to the
exit section contribute to the total suspended load during ordinary flood events.
During the studied period, runoff controls the total suspended sediment budget. The
suspended load from the events represents on average the 38 % of the seasonal
suspended sediment budget, but it can reach almost 100% in some seasons. It was not
possible to establish a flow peak threshold that determines the advance or delay of the
hydrograph peak with respect to the sedigraph peak, probably due to the small
size of the catchment and the bedload fraction characterizing the total transport of
some of the events. The disconnectivity present in the upper part of the Rio Cordon
basin seems to be the determining factor of the low in-channel sediment presence
despite the high erosive potential of rainfall. This research was supported by the
Italian Research Project of Relevant Interest PRIN2010-2011, prot. 20104ALME4,
ITSE; and by the University of Padova Research Project CPDA149091- WoodAlp |
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