TY - JOUR
T1 - A simplified 2D model for meander migration with physically-based bank evolution
AU - Motta, Davide
AU - Abad, Jorge D.
AU - Langendoen, Eddy J.
AU - Garcia, Marcelo H.
N1 - Funding Information:
This research was supported by an agreement from the U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station and using funds provided by the Bureau of Land Management through the sale of public lands as authorized by the Southern Nevada Public Land Management Act. This work was performed under Specific Cooperative Agreement No. 58-6408-8-265 between the Department of Civil and Environmental Engineering at the University of Illinois at Urbana-Champaign and the U.S. Department of Agriculture, Agricultural Research Service, National Sedimentation Laboratory. Inci Guneralp is gratefully acknowledged for providing the aerial pictures and the channel centerlines of the Mackinaw River.
PY - 2012/8/15
Y1 - 2012/8/15
N2 - The rate of migration, calculated by numerical models of river meandering, is commonly based on a method that relates the rate of migration to near-bank excess velocity multiplied by a dimensionless coefficient. Notwithstanding its simplicity, since the early 1980s this method has provided important insight into the long-term evolution of meander planforms through theoretical exercises. Its use in practice has not been as successful, because the complexity of the physical processes responsible for bank retreat, the heterogeneity in floodplain soils, and the presence of vegetation, make the calibration of the dimensionless coefficient rather challenging. This paper presents a new approach that calculates rates of meander migration using physically-based streambank erosion formulations. The University of Illinois RVR Meander model, which simulates meandering-river flow and bed morphodynamics, is integrated with algorithms for streambank erosion of the US Department of Agriculture channel evolution computer model CONCEPTS. The performance of the proposed approach is compared to that of the more simple classic method through the application to several test cases for idealized and natural planform geometry. The advantages and limitations of the approach are discussed, focusing on simulated planform pattern, the impact of soil spatial heterogeneity, the relative importance of the different processes controlling bank erosion (hydraulic erosion, cantilever, and planar failure), the requirements for obtaining stable migration patterns (centerline filtering and interpolation of bank physical properties), and the capability of predicting the planform evolution of natural rivers over engineering time scales (i.e., 50 to 100. years). The applications show that the improved physically-based method of bank retreat is required to capture the complex long-term migration patterns of natural channels, which cannot be merely predicted from hydrodynamics only.
AB - The rate of migration, calculated by numerical models of river meandering, is commonly based on a method that relates the rate of migration to near-bank excess velocity multiplied by a dimensionless coefficient. Notwithstanding its simplicity, since the early 1980s this method has provided important insight into the long-term evolution of meander planforms through theoretical exercises. Its use in practice has not been as successful, because the complexity of the physical processes responsible for bank retreat, the heterogeneity in floodplain soils, and the presence of vegetation, make the calibration of the dimensionless coefficient rather challenging. This paper presents a new approach that calculates rates of meander migration using physically-based streambank erosion formulations. The University of Illinois RVR Meander model, which simulates meandering-river flow and bed morphodynamics, is integrated with algorithms for streambank erosion of the US Department of Agriculture channel evolution computer model CONCEPTS. The performance of the proposed approach is compared to that of the more simple classic method through the application to several test cases for idealized and natural planform geometry. The advantages and limitations of the approach are discussed, focusing on simulated planform pattern, the impact of soil spatial heterogeneity, the relative importance of the different processes controlling bank erosion (hydraulic erosion, cantilever, and planar failure), the requirements for obtaining stable migration patterns (centerline filtering and interpolation of bank physical properties), and the capability of predicting the planform evolution of natural rivers over engineering time scales (i.e., 50 to 100. years). The applications show that the improved physically-based method of bank retreat is required to capture the complex long-term migration patterns of natural channels, which cannot be merely predicted from hydrodynamics only.
KW - Bank erosion
KW - Computer model
KW - Meander migration
KW - Migration coefficient
KW - Planform shape
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U2 - 10.1016/j.geomorph.2011.06.036
DO - 10.1016/j.geomorph.2011.06.036
M3 - Article
AN - SCOPUS:84862518552
SN - 0169-555X
VL - 163-164
SP - 10
EP - 25
JO - Geomorphology
JF - Geomorphology
ER -