Becky Goodsell and Eric Scott are thanked for field assistance. Antony Smith assisted with figure
production. The field campaign wa funded by NERC Grant NE/G005427/1 and NERC Geophysical Equipment Facility Loan 892. Richard  Williams was funded by NERC Grant NE/G005427/1during fieldwork and by a British Hydrological Society Travel Grant whilst visiting NIW

Ackers

Asahi

Ashmore

Bagnold

Baldassarre

Blott

Brasington

Bridge

Carbonneau

Carrivick

Church

Cook

Crosato

D. M. Hicks

Dietrich

Egiazaroff

Ferguson

Feurich

Fischer-Antze

Gaeuman

Gomez

Haschenburger

Hicks

Hirano

Howard

Ikeda

J. Brasington

Jang

Javernick

Jowett

Karmaker

Kelly

Kleinhans

Klingeman

Knight

Lallias-Tacon

Lane

Leopold

Lesser

Lotsari

McMillan

Milan

Montgomery

Moretto

Mosselman

Murray

Nicholas

Passalacqua

R. D. Williams

R. Measures

Rennie

Saltelli

Schuurman

Sloff

Stelling

Talmon

Tarolli

Tenzer

Tucker

Warburton

Wegen

Werff

Wheaton

Wilcock

Williams

Wolman

Wright

Yager

Yang

Ziliani

Water Resources Research

Numerical morphological modelling of braided rivers, using a physics-based approach, is increasingly used as a technique to explore controls on river pattern and, from an applied perspective, to simulate the impact of channel modifications. This paper assesses a depth averaged non-uniform sediment model (Delft3D) to predict the morphodynamics of a 2.5 km long reach of the braided Rees River, New Zealand, during a single high-flow event. Evaluation of model performance primarily focused upon using high-resolution Digital Elevation Models (DEMs) of Difference, derived from a fusion of terrestrial laser scanning and optical empirical bathymetric mapping, to compare observed and predicted patterns of erosion and deposition, and reach scale sediment budgets. For the calibrated model, this was supplemented with planform metrics (e.g. braiding intensity). Extensive sensitivity analysis of model functions and parameters was executed, including consideration of numerical scheme for bedload component calculations, hydraulics, bed composition, bedload transport and bed slope effects, bank erosion and frequency of calculations. Total predicted volumes of erosion and deposition corresponded well to those observed. The difference between predicted and observed volumes of erosion was less than the factor of two that characterises the accuracy of the Gaeuman et al. bedload transport formula. Grain size distributions were best represented using two-phi intervals. For unsteady flows, results were sensitive to the morphological time scale factor. The approach of comparing observed and predicted morphological sediment budgets shows the value of using natural experiment datasets for model testing. Sensitivity results are transferable to guide Delft3D applications to other rivers

Williams, R.D.

Measures, R.

Hicks, M.

Brasington, J.

Enlighten

English

Assessment of a numerical model to reproduce event-scale erosion and deposition distributions in a braided river

Assessment of a numerical model to reproduce event-scale erosion and deposition distributions in a braided river

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