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| Titel |
Rainfall intensity-duration curve for bedload transport initiation in the Erlenbach, Switzerland |
| VerfasserIn |
Alexandre Badoux, Jens Turowski, Dieter Rickenmann |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250034435
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| Zusammenfassung |
| The transport of large amounts of bedload in water courses can drastically aggravate
hazardous situations during flood events, and often strongly affects resulting flood damage.
The onset of transport is controlled by factors which are difficult to assess, not to mention
measure or monitor, and the accurate prediction of transport rates has proved to be
notoriously difficult. Channel discharge represents the primary control of sediment transport
rates in mountain streams; however, this parameter is rarely measured in small catchments
and thus it is often impossible to use it as a predictor of hazardous sediment events in
mountain communities. With the steady development of precipitation measurement networks
in Alpine regions and the progresses accomplished in radar precipitation estimation over the
last 10 to 15 years, rainfall lends itself as a means for warning purposes in sediment prone
areas.
Here, we describe interpretation of rainfall measurements from the Erlenbach, a 0.7 km2
catchment located within a hydrologic research site in the Alptal valley in central
Switzerland. Using rainfall data from within the catchment from 1986-2009, we investigate
thresholds for bedload transport activity considering parameters such as storm duration and
rainfall intensity. With indirect bedload sensor measurements, continuous discharge
measurements and the availability of a retention basin downstream of the gauging station, the
Erlenbach provides all necessary elements for the investigation of transport processes.
Roughly 210 rainfall events were identified during which abundant sediment transport
occurred in the study catchment and an intensity-duration threshold line was subsequently
defined (I = 8.3D-0.93), where I is in [mm/h] and D is in [h]), above which sediment
transport activity has to be expected. This threshold could represent the basis for prediction of
bedload transport in ungauged streams. By considering severe rainfall events that did not
trigger any activity in the stream, we will be able to better assess the uncertainty of
the identified intensity-duration threshold, and to estimate a false alarm rate and
its implication on the practicability of our approach for early warning purposes. |
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