Bank erosion is a natural geomorphological process which affects a wide range of physical, ecological and socio-economic issues in the fluvial environment. Among the others, the impacts include loss of lands, damage to structure and infrastructures and dynamics of sediments, nutrients and contaminants. Hence, it is not surprising how riverbank retreat is closely related to the risk assessment. Despite many progresses have been made in understanding and modelling bank erosion, further investigations are needed to better understand processes occurring on riverbank totally or partially composed of relatively coarse sediments. Therefore, the general aim of this study is to give a contribution in understanding and modelling processes, with particular focusing on gravel banks. The study is organized to provide a general framework of analysis at different spatial scales, using as a reference study case the Cecina River (Pisa, Italy). At the catchment scale, riverbank processes were studied with the specific aim to identify the variability of bank features (geometry and composition), the dominant mechanisms of retreat and their spatial distribution. Different methods to predict the lateral instabilities were also undertaken in order to pinpoint causes and factors which control the occurrence of different mechanisms of retreat. At the reach scale, numerical models were employed with the aim of exploring methods for a combined analysis which couples different mechanisms of retreat, with particular focus on the inclusion of near-bank shear stresses. Moreover, based on results of the previous analyses, a framework for risk analysis due to bank erosion was developed. The objective of the analyses carried out at the bank scale, was to better understand the basic processes occurring in relatively coarse bank sediments, in particular the occurrence of mass instability in the absence of fluvial erosion. In order to address the objective, a physical model of a bank composed by gravel and sand was built, and some experiments simulating the behaviour of the bank during a hydrograph were carried out. The tests allowed for the identification of different mechanisms of failure and for the analysis of the factor affecting non cohesive bank stability.


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    Titel :

    Numerical and physical modelling of bank retreat in gravel-bed rivers


    Weitere Titelangaben:

    Numerische und physikalische Modellierung von Ufererosion in Kiesflüssen


    Beteiligte:
    Nardi, Laura (Autor:in) / Universitätsbibliothek Braunschweig (Gastgebende Institution) / Dittrich, Andreas (Akademische:r Betreuer:in)

    Erscheinungsdatum :

    2011



    Medientyp :

    Sonstige


    Format :

    Elektronische Ressource


    Sprache :

    Englisch


    Klassifikation :

    DDC:    627