2D numerical simulation of meander morphology

Mohd. Sarfaraz Banda,Jochen Aberle,Stephan Niewerth

doi:10.1051/e3sconf/20184005062

Mohd. Sarfaraz Banda, Jochen Aberle + Show 1 more

Open Access

https://doi.org/10.1051/e3sconf/20184005062

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Abstract

This paper describes the application of the two-dimensional (2D) modelling approach implemented in the open-source code Delft3D for the simulation of morphological development of a natural meandering river. A specific reach of the Dhaleshwari River (Bangladesh) for which field data has been available served as case study. The bed morphology and meander planform adjustment in the study area were simulated over a 10-year period considering a time-varying discharge scenario. The results showed that the 2D model was able to reproduce morphological characteristics such as scour depth, bank erosion and pool-riffle morphology, even though the model showed some deficiencies to reproduce bankfull channel width and transverse bed slopes. Regarding the planimetric evolution, the planform parameters (i.e., meander belt width, meander wavelength and radius of curvature) confirmed that the model results are realistic and are in agreement with results reported in the literature.

Highlights

The need for the prediction of the planform of natural meandering rivers arises from the fact that the migration of their channels can threaten the infrastructure as well as the safety and effectivity of hydraulic structures
Using field data from the meandering Dhaleshwari River in Bangladesh, the objective of the present study is to explore the capability of the open-source code Delft3D to simulate the adaption of both planform dynamics and bed topography of natural meandering rivers
The 2D modelling approach with a parameterization for secondary flow, which is characteristic for curved channels, was used to reproduce bed topography and planform adjustment in the Dhaleshwari River for a period of 10 years (2003-2013)

Summary

Introduction

The need for the prediction of the planform of natural meandering rivers arises from the fact that the migration of their channels can threaten the infrastructure as well as the safety and effectivity of hydraulic structures. This means that the dynamic evolution of meandering rivers can impose significant problems for water resources management. Most of the existing numerical modelling studies on meandering rivers have been used to reproduce results from laboratory investigations (e.g., [6]) or have focused on hypothetical rivers (e.g., [7]) Their application to simulate the morphological development of natural meandering rivers is scarce. This can be attributed to the fact that only few field data sets exist which cover typical morphological time-scales of years to decades, i.e. field data sets allowing for model validation

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