La connectivité sédimentaire dans la haute chaîne pyrénéenne par l’analyse de la crue de juin 2013 : le rôle des formations superficielles

Abstract : The (in)efficiency of sediment connectivity between hillslopes and river channel is highlighted during extreme hydro-climatic events. The high-magnitude flood of June 2013 in the Central Pyrenees has showed the role of inherited surficial sediment storages in the feeding of river sediment load. In mountain areas, morphometric parameters are also a controlling factor of the sediment connectivity. In this study, sediment routing during the flood studied in the four most affected catchments. The analysis is based on a GIS morphometric index of sediment connectivity derived from 5-m DTM. It is combined with classical geomorphic mapping of surficial sediment storages and active areas during the flood. This methodology allowed to compare the structural connectivity of sub-catchments and surficial sediment storages with functional connectivity during the flood. Compare to the historical past major floods, it displayed the low sediment supply of small tributaries with high average connectivity. Headwater areas and glacial sediment storages have not supplied sediments during the flood and acted as disconnected areas according to the index. Conversely, post glacial sediment storages in the valley bottom were the most connected and contributive stores. Lateral sediment connectivity occurred mainly between storages of the mid and low part of the valley which are adjacent to the main river. Our study highlights the potential of the morphometric index supported by geomorphological mapping to characterize the central Pyrenean connectivity in a context of a low frequency high magnitude events.
Complete list of metadatas

Cited literature [10 references]  Display  Hide  Download

https://hal.archives-ouvertes.fr/hal-01928029
Contributor : Jean-Michel Carozza <>
Submitted on : Monday, May 20, 2019 - 11:58:18 AM
Last modification on : Wednesday, May 29, 2019 - 1:18:17 AM

File

BLANPIED_et_al.pdf
Publisher files allowed on an open archive

Identifiers

Collections

Citation

Johann Blanpied, Jean-Michel Carozza, Jean-Marc Antoine. La connectivité sédimentaire dans la haute chaîne pyrénéenne par l’analyse de la crue de juin 2013 : le rôle des formations superficielles. Géomorphologie : relief, processus, environnement, Groupe français de géomorphologie (GFG), 2018, 24 (4), pp.389-402. ⟨10.4000/geomorphologie.12718⟩. ⟨hal-01928029⟩

Share

Metrics

Record views

44

Files downloads

29