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Controlling factors of the size and location of large gully systems: a regression-based exploration using reconstructed pre-erosion topography
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Orientador(es)
Resumo(s)
The role of different factors potentially affecting the size and location of large gully systems is explored in two
tributary basins of the Tagus River (S Portugal). The hillslopes of these basins, corresponding to tertiary sedimentary
formations, are affected by hundreds of large gully systems, varying in extent from somewhat b200 m2 to
N3 ha. A study set of 90 gully systems were vectorized from aerial ortophotos and analysed in relation to a set
of potential control variables, obtained by reconstructing the pre-erosion topography. Multiple linear regression
and logistic regression were combined in order to investigate controls over the general morphometry of these
landforms (area, perimeter and sinuosity) and their location in the respective basins. Results indicate that
gully systems initiated as bank gullies in response to an incision by the drainage network in both basins and
then evolved as a function of upslope contributing area, developing progressively more sinuous outlines as a result
of headcut bifurcation. Pre-erosion topographic formwas shown to have only a marginal effect, with results
suggesting gully systems have grown essentially throughmassmovements in headcuts and sidewalls, influenced by subsurface water.
Descrição
Palavras-chave
Gully erosion Gully complex Logistic regression Multiple linear regression
Contexto Educativo
Citação
Bergonse, Rafaello, & Reis, Eusébio. (2016). Controlling factors of the size and location of large gully systems: a regression-based exploration using reconstructed pre-erosion topography. Catena, 147, 621-631. https://doi.org/10.1016/j.catena.2016.08.014
Editora
Elsevier