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Local high‐slope effects on sediment transport and fluvial bed form dynamics
Author(s) -
Francalanci Simona,
Solari Luca,
Toffolon Marco
Publication year - 2009
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2008wr007290
Subject(s) - flattening , bed load , geology , fluvial , nonlinear system , sediment transport , flow (mathematics) , geotechnical engineering , sediment , mechanics , geomorphology , geometry , physics , mathematics , structural basin , quantum mechanics , astronomy
We investigate the morphodynamic evolution of an arbitrarily tilted, coarse, mobile bed under the action of a free surface water flow. The analysis is based on the experimental observations of the evolution of a mobile bed from its initial, laterally tilted configuration to the final laterally flat state, due to the presence of a lateral component of bed load transport. Measurements of the bed topography at different times allow one to reconstruct the flattening process. The experimental observations are interpreted by means of a three‐dimensional numerical hydromorphodynamic model employing different relationships, linear and nonlinear, to evaluate bed load intensity and direction. The analysis shows that the inclusion of nonlinear gravitational effects in the description of the bed load leads to a more satisfactory description of the bed evolution. This finding opens important issues on how the inclusion of the nonlinear gravitational effects on the bed load can affect the morphodynamic evolution of complex bed topography occurring in natural rivers. To investigate this point, an application to the evolution of river bars is presented.