HR: 14:10h
AN: H33I-03    [Abstracts]
TI: Long-term morphological evolution of tidal embayments: Channel Newtwork incision and early development.
AU: * D`Alpaos, A
EM: adalpaos@idra.unipd.it
AF: Dipartimento IMAGE -University of Padova, Via Loredan 20, Padova, Pd 35131 Italy
AU: Lanzoni, S
EM: lanzo@idra.unipd.it
AF: Dipartimento IMAGE -University of Padova, Via Loredan 20, Padova, Pd 35131 Italy
AU: Marani, M
EM: marani@idra.unipd.it
AF: Dipartimento IMAGE -University of Padova, Via Loredan 20, Padova, Pd 35131 Italy
AU: Marani, M
EM: marani@idra.unipd.it
AF: International Centre of Hydrology 'Dino Tonini', Via Loredan 20, Padova, Pd 35131 Italy
AU: Fagherazzi, S
EM: sergio@csit.fsu.edu
AF: School of Computational Science and Information Technology-Florida State University, Dirac Science Library Office 462 DSL , Tallahassee, FL 32306-4120 United States
AU: Rinaldo, A
EM: adalpaos@idra.unipd.it
AF: Dipartimento IMAGE -University of Padova, Via Loredan 20, Padova, Pd 35131 Italy
AU: Rinaldo, A
EM: adalpaos@idra.unipd.it
AF: International Centre of Hydrology 'Dino Tonini', Via Loredan 20, Padova, Pd 35131 Italy
AB: The long-term morphological evolution of tidal landforms in response to physical and ecological forcings is a subject of great theoretical and practical importance. Towards the goal of a comprehensive theoretical framework suitable for large-scale, long-term applications, we set up a mathematical model of tidal channel network initiation and early development, which is assumed to act on timescales considerably shorter than those of other landscape-forming eco-morphodynamical processes of tidal systems. A suitable hydrodynamic model capable of describing the key landforming features is coupled with a morphodynamic model which retains the description of the main physical processes responsible for tidal channel initiation and network ontogeny. The model is designed for the direct inclusion of eco-morphological mechanisms like (organic and inorganic) soil production and transport, vegetation dynamics, tidal meandering and relative sea-level regressions/transgressions, which are not discussed here because of their different characteristic timescales. We assume that water surface elevation gradients provide key elements for the description of the processes that drive incision, in particular the exceedence of a stability (or maintenance) suitably defined shear stress. The model describes tidal network initiation and its progressive headward extension through the carving of incised cross-sections where the local shear stress exceeds a predefined, possibly site-dependent threshold value. Capture of divides and migration of tidal watersheds are derived. Validation of the results against observed network properties, distinctive network statistics and structural heterogeneities are critically presented.
DE: 1815 Erosion and sedimentation
DE: 1824 Geomorphology (1625)
DE: 1848 Networks
DE: 1890 Wetlands
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting