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| Titel |
Modelling shallow landslide susceptibility by means of a subsurface flow path connectivity index and estimates of soil depth spatial distribution |
| VerfasserIn |
C. Lanni, M. Borga, R. Rigon, P. Tarolli |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 16, no. 11 ; Nr. 16, no. 11 (2012-11-02), S.3959-3971 |
| Datensatznummer |
250013552
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| Publikation (Nr.) |
 copernicus.org/hess-16-3959-2012.pdf |
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| Zusammenfassung |
Topographic index-based hydrological models have gained wide use to describe
the hydrological control on the triggering of rainfall-induced shallow
landslides at the catchment scale. A common assumption in these models is
that a spatially continuous water table occurs simultaneously across the
catchment. However, during a rainfall event isolated patches of
subsurface saturation form above an impeding layer and their
hydrological connectivity is a necessary condition for lateral flow initiation at a point on the hillslope.
Here, a new hydrological model is presented, which allows us to account for the
concept of hydrological connectivity while keeping the simplicity of the
topographic index approach. A dynamic topographic index is used to describe
the transient lateral flow that is established at a hillslope element when
the rainfall amount exceeds a threshold value allowing for (a) development
of a perched water table above an impeding layer, and (b) hydrological
connectivity between the hillslope element and its own upslope contributing
area. A spatially variable soil depth is the main control of hydrological
connectivity in the model. The hydrological model is coupled with the
infinite slope stability model and with a scaling model for the rainfall
frequency–duration relationship to determine the return period of the
critical rainfall needed to cause instability on three catchments located in
the Italian Alps, where a survey of soil depth spatial distribution is
available. The model is compared with a quasi-dynamic model in which the
dynamic nature of the hydrological connectivity is neglected. The results
show a better performance of the new model in predicting observed shallow
landslides, implying that soil depth spatial variability and connectivity
bear a significant control on shallow landsliding. |
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