Development of a meandering channel caused by the planform shape of the river bank

Abstract

Abstract. Due to a typhoon and a stationary rain front, record amounts of rain fell in September 2011, and the largest class of discharge in recorded history was observed in the Otofuke River of eastern Hokkaido in Japan, and extensive bank erosion occurred in various parts of the river channel. Damages were especially serious in the middle reaches, where part of a dike was washed out. The results of a post-flood survey suggested that the direct cause of the dike breach was lateral advance of the bank erosion associated with the development of meandering channels. As the related development mechanism and predominant factors have not yet been clarified, this remains a priority from the viewpoint of disaster prevention. A past study on the development of meandering channels was reported by Shimizu et al. (1996). In this study, the meandering channel development process was reproduced using a slope failure model that linked bank erosion with bed changes. The study attempted to clarify the meandering development mechanism in the disaster and its predominant factors by using this model. The analysis properly reproduced the characteristics of the post-flood meandering waveforms. Therefore, it is suggested that the development of meandering during the flood attributed to the propagation of meandering downstream, which is triggered by the meandering flow from the meandering channel in the upstream, which also suggests that this propagated meandering then caused a gradual increase of meandering amplitude accompanied by bank erosion in the recession period of the flood.

High spatiotemporal resolution of river planform dynamics from Landsat: The RivMAP toolbox and results from the Ucayali River

“…However, the difficulty of observing multidecadal river migrations at high temporal and spatial resolutions has hampered efforts to fully resolve natural planform dynamics [ Hooke , ]. Observations made over longer periods (decades to centuries) are often compiled from various sources such as historic maps, surveys, and aerial photographs that do not capture planform changes [ Hooke and Redmond , ; Harmar and Clifford , ; Yao et al ., ] due to nonstationary flow regimes [ Bradley and Smith , ; Kiss and Blanka , ], individual floods [ Hickin and Sichingabula , ; Nagata et al ., ], cutoffs [ Hooke , ; Zinger et al ., ; Martha et al ., ], or human activities [ Asner et al ., ; Midha and Mathur , ; Słowik , ; Rhoads et al ., ]. On the other hand, studies that resolve detailed migration dynamics at event‐scale frequencies from aerial photographs are often constrained to significantly shorter durations than the inception‐to‐cutoff time of a typical meander bend [e.g., Bertoldi et al ., ].…”

The life of a meander bend: Connecting shape and dynamics via analysis of a numerical model

“…This work rested upon previous research that developed metrics of planform geometry through analysis of both real [ Jefferson , ; Dury , ; Leopold and Wolman , ] and experimental [ Quraishy , ; Friedkin , ] meanders. Since then, significant contributions have been made via an abundance of field studies that apply these metrics to real river centerlines derived from combinations of historic maps [ Hooke and Redmond , ], aerial photography [ Yao et al , ; Nagata et al , ], and field surveys [ Legleiter , ].…”

Extreme flood‐driven fluvial bank erosion and sediment loads: direct process measurements using integrated Mobile Laser Scanning (MLS) and hydro‐acoustic techniques

“…Despite the postulated importance of cyclone-driven flows on bank erosion and suspended sediment transport (Darby et al, 2013), to our knowledge there have been no direct measurements of bank retreat before, during and after cyclone driven flood events, with previous studies limited to analysis of remotely sensed imagery and event-based modelling (Buraas et al, 2014;Nagata et al, 2014;Magilligan et al, 2015). The scarcity of direct bank and flow monitoring data likely results from two key issues: (i) the equipment available to rapidly characterise the river bed/banks has, until recently, been inadequate, especially for capturing morphological data at high spatial resolution (10 À3 -10 À1 m; Brasington et al, 2012) over large areas (10 2 -10 4 m; Brasington et al, 2012); and (ii) the challenges associated with deployment of this equipment during flood events presents considerable logistical difficulties.…”