Unsteady 1D flow model of a river with partly vegetated floodplains - application to the Rhine River

Abstract A relatively simple unsteady flow model was proposed which estimates velocities, friction factors and the components of discharge in the main channel and on the floodplains simultaneously. Bottom roughness of the main channel and the floodplains, the flow resistance of vegetation on the floodplains and the flow resistance caused by the momentum transfer between the main channel and the floodplains were included in the model using Nuding's method. A pre-processing program was developed to convert topographic field data that can be derived from a digital terrain model into cross-sectional input data of the flow model. The model was applied to a 28-km reach on the Upper Rhine for three steady flow cases and for two unsteady flood event cases to investigate resistance effects of partly vegetated floodplains. Computed discharges and water levels correlated well with the measured data. It was found that a significant component of discharge was transported by the floodplains in some cross-sections during high flows.

[1]  D. Knighton.  Fluvial forms and processes , 1984 .

[2]  M. Lambert,et al.  Discharge prediction in straight compound channels using the mixing length concept , 1996 .

[3]  Stephen E. Darby,et al.  Predicting Stage-Discharge Curves in Channels with Bank Vegetation , 1996 .

[4]  R. Sellin.  A laboratory investigation into the interaction between the flow in the channel of a river and that over its flood plain , 1964 .

[5]  André Robert,et al.  Scales of boundary resistance in coarse-grained channels : turbulent velocity profiles and implications , 2001 .

[6]  Eric M. Valentine,et al.  A practical method for predicting the total discharge in mobile and rigid boundary compound channels , 2002 .

[7]  E. P. Evans,et al.  Reducing uncertainty in conveyance estimation , 2002 .

[8]  Andreas Dittrich,et al.  1D unsteady-state flow simulation of a section of the upper Rhine , 2002 .

[9]  Terhi Helmiö,et al.  Unsteady 1D flow model of compound channel with vegetated floodplains , 2002 .

[10]  M. Gordon Wolman,et al.  Flow resistance in sinuous or irregular channels , 1960 .

[11]  A. Knighton.  Asymmetry of river channel cross‐sections: Part II. mode of development and local variation , 1982 .

[12]  Ronald R. Copeland,et al.  Hydraulic Design of Stream Restoration Projects , 2001 .

[13]  E. P. Evans,et al.  Scoping Study for Reducing Uncertainity in River Flood Conveyance , 2001 .

[14]  J. Järvelä.  Determination of flow resistance of vegetated channel banks and floodplains , 2002 .

[15]  Erik Pasche.  Turbulenzmechanismen in naturnahen Fliessgewässern und die Möglichkeiten ihrer mathematischen Erfassung , 1984 .

[16]  Hunter Rouse,et al.  Critical Analysis of Open-Channel Resistance , 1965 .

[17]  A. Knighton,et al.  Asymmetry of river channel cross‐sections: Part I. Quantitative indices , 1981 .

[18]  P. Ackers.  Flow formulae for straight two-stage channels , 1993 .

[19]  Colin R. Thorne,et al.  Predicting Influence of Bank Vegetation on Channel Capacity , 1992 .

[20]  E. Pasche,et al.  Overbank Flow with Vegetatively Roughened Flood Plains , 1985 .