loading page

Hydrogeomorphology of asymmetric meandering channels: experiments and field evidence
  • +3
  • Jorge Darwin Abad,
  • Davide Motta,
  • Leo Guerrero,
  • Marco Paredes,
  • Julio M Kuroiwa,
  • Marcelo H García
Jorge Darwin Abad
Research, Education and Development, RED YAKU

Corresponding Author:[email protected]

Author Profile
Davide Motta
Northumbria University
Author Profile
Leo Guerrero
Louisiana State University
Author Profile
Marco Paredes
SENAMHI
Author Profile
Julio M Kuroiwa
Universidad Nacional de Ingenieria
Author Profile
Marcelo H García
University of Illinois at Urbana Champaign
Author Profile

Abstract

Meandering channels display complex planform configurations with upstream- and downstream- skewed bends. Bend orientation is linked to near-field hydrodynamics, bed morphodynamic regime, bank characteristics, riparian vegetation, and geological environment, which are the modulating factors that act specially in high-amplitude and high-sinuosity conditions. Based on the interaction between hydrodynamics and morphodynamics, previous studies have suggested that sub- (β < βR) and super-resonant (β > βR) morphodynamic regimes (where β is the half width-to-depth ratio of the channel, and βR is the resonance condition) may trigger a particular bend orientation (upstream- and downstream-skewed, respectively). However, natural rivers exhibit both US-skewed and DS-skewed bend patterns along the same reach, independently of the morphodynamic regime. Little is known about the hydrogeomorphology (forced and free morphodynamic patterns) under these bend orientations. Herein, using the asymmetric Kinoshita laboratory channel, experiments under sub- and super-resonant conditions (with presence or absence of free bars) for upstream-and downstream-skewed conditions are performed. Additional, detailed field measurements at US-skewed and DS-skewed bends of different skewness along the Tigre River in Peru are presented. Conditions at field scale at high-sinuosity and high-amplitude bends filter out the influence of the morphodynamic regime, where nonlinear processes (e.g. width variation) directly the development of the three-dimensional flow structure, then to the erosional and depositional patterns, and then to the lateral migration patterns.