University of Illinois Urbana-Champaign

A physically-based bank erosion model for composite river banks: Application to Mackinaw River, Illinois

Waterman, David M.; Garcia, Marcelo H.; Chow, Ven Te

Content Files
WatermanGarciaChow_2013.pdf

Permalink

https://hdl.handle.net/2142/90120

Description

Title
A physically-based bank erosion model for composite river banks: Application to Mackinaw River, Illinois
Author(s)
  • Waterman, David M.
  • Garcia, Marcelo H.
  • Chow, Ven Te
Contributor(s)
University of Illinois at Urbana-Champaign
Issue Date
2013-05
Keyword(s)
  • Water resources center
  • Water resources center--Illinois
  • Hydrology and hydraulics
  • Mackinaw River
  • Erosion
  • Rivers
Date of Ingest
2016-05-18T19:59:17Z
Geographic Coverage
Illinois (state)
Abstract
Meandering river migration over large spatial and temporal scales has traditionally been numerically simulated using a bank erosion submodel that calculates the eroding bank migration rate as the product of the near-bank excess flow velocity and a dimensionless migration coefficient. The latter value is an empirical parameter calibrated to historical observations. In efforts to improve upon the traditional model, recent research has followed two approaches: (a) provide a means of estimating the dimensionless migration coefficient based on field measurements; and (b) discard the traditional migration coefficient approach to develop a bank erosion submodel based on the actual formulations that dictate fluvial erosion rates and mass failure which determine bank migration. The latter physics-based approach was recently implemented into the numerical model RVR Meander developed by the Ven Te Chow Hydrosystems Laboratory at the University of Illinois in Urbana-Champaign (Motta et al, 2012a); however, the governing equations used for fluvial erosion strictly apply only to banks comprised of cohesive soils. In that formulation the fluvial erosion rate is linearly dependent on the excess boundary shear stress. This study explores whether a similarly simple formulation can describe in a gross sense the migration of river banks comprised entirely of non-cohesive soil or composite banks consisting of non-cohesive soil at the base overlain by cohesive soil. Numerical modeling of both fluvial erosion and shallow avalanche mass failures that occur simultaneously during non-cohesive bank deformation reveal that the bank migration rate is strongly non-linear with respect to the boundary shear stress (exponent greater than 1) when considering non-cohesive bank materials. A methodology is described for developing a site specific non-cohesive bank erosion submodel that is valid and computationally practicable over the desired large spatial and temporal scales relevant to models such as RVR Meander. The new methodology allows issues such as flow regime modifications to be incorporated to change the model parameters, which was not possible using the traditional empirical approach. The numerical modeling performed in this study also provides fundamental insights into deformation of non-cohesive river banks: it demonstrates that high flow events tend to cause bank slope reduction, with lower flow events tending to rejuvenate the steepness of the bank; it quantifies the importance of prior erosional history in influencing bank migration rates; and it quantifies the feedback of basal armoring on deformation of the unarmored region.
Publisher
University of Illinois at Urbana-Champaign. Water Resources Center
Type of Resource
text
Genre of Resource
Report (Grant or Annual)
Language
en
Permalink
http://hdl.handle.net/2142/90120
Sponsor(s)/Grant Number(s)
  • U.S. Department of the Interior
  • U.S. Geological Survey
Copyright and License Information
Copyright 2013 held by David M. Waterman, Marcelo H. Garcia, Ven Te Chow

Owning Collections

Illinois Water Resources Center - Hydrology and Hydraulics PRIMARY