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| Titel |
Coupled prediction of flood response and debris flow initiation during warm- and cold-season events in the Southern Appalachians, USA |
| VerfasserIn |
J. Tao, A. P. Barros |
| 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 ; 18, no. 1 ; Nr. 18, no. 1 (2014-01-31), S.367-388 |
| Datensatznummer |
250120264
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| Publikation (Nr.) |
 copernicus.org/hess-18-367-2014.pdf |
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| Zusammenfassung |
| Debris flows associated with rainstorms are a frequent and devastating
hazard in the Southern Appalachians in the United States. Whereas warm-season
events are clearly associated with heavy rainfall intensity, the same
cannot be said for the cold-season events. Instead, there is a relationship
between large (cumulative) rainfall events independently of season, and thus
hydrometeorological regime, and debris flows. This suggests that the
dynamics of subsurface hydrologic processes play an important role as a
trigger mechanism, specifically through soil moisture redistribution by
interflow. We further hypothesize that the transient mass fluxes associated
with the temporal-spatial dynamics of interflow govern the timing of shallow
landslide initiation, and subsequent debris flow mobilization. The first
objective of this study is to investigate this relationship. The second
objective is to assess the physical basis for a regional coupled flood
prediction and debris flow warning system. For this purpose, uncalibrated
model simulations of well-documented debris flows in headwater catchments of
the Southern Appalachians using a 3-D surface–groundwater hydrologic model
coupled with slope stability models are examined in detail. Specifically, we
focus on two vulnerable headwater catchments that experience frequent debris
flows, the Big Creek and the Jonathan Creek in the Upper Pigeon River Basin,
North Carolina, and three distinct weather systems: an extremely heavy
summertime convective storm in 2011; a persistent winter storm lasting
several days; and a severe winter storm in 2009. These events were selected
due to the optimal availability of rainfall observations; availability of
detailed field surveys of the landslides shortly after they occurred, which
can be used to evaluate model predictions; and because they are
representative of events that cause major economic losses in the region. The
model results substantiate that interflow is a useful prognostic of
conditions necessary for the initiation of slope instability, and should
therefore be considered explicitly in landslide hazard assessments.
Moreover, the relationships between slope stability and interflow are
strongly modulated by the topography and catchment-specific geomorphologic
features that determine subsurface flow convergence zones. The three
case studies demonstrate the value of coupled prediction of flood response
and debris flow initiation potential in the context of developing a regional
hazard warning system. |
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