Neck Cutoffs on Meandering Rivers
As meandering rivers migrate laterally across their floodplains, their stream length increases while channel slope decreases. Periodically, the stream length is shortened by means of a cutoff, a new channel pathway that the river erodes through the floodplain. A neck cutoff forms when the upstream and downstream limbs of a meander bend migrate toward each other until eventually they intersect and cause the river to shorten. The location and timing of cutoff events are difficult to predict, and as a result the hydrodynamics and morphodynamics during evolving cutoff channels remains poorly understood. We have been trying to address these research gaps by studying multiple neck cutoffs on the White River in central Arkansas by collecting detailed measurements of channel bathymetry and three-dimensional flow structure.
Morphodynamics of point bars on complex meandering rivers
The spatial patterns of erosion and deposition in meandering rivers produce characteristics depositional features along the inner banks called point bars. Within these point bar depositional sequences, the sedimentology and stratigraphy provide insights into the sediment transport capacity and planform evolution of the channel, which is of critical importance for interpreting and reconstructing paleoenvironments from the rock record. Despite and abundance of past work on the internal structure and stratigraphy of point bars, our knowledge of the morphodynamics of point bars on complex meander bends is surprisingly sparse. This project seeks to relate the style (e.g. extension, translation, rotation) and rate of bank migration to the surface morphology and subsurface structure and sedimentology of point bars on highly sinuous meandering rivers.
Influence of vegetation on dynamics of meandering rivers
The presence of floodplain vegetation along river banks (riparian vegetation) and vegetation within river channels (large wood and grasses) can have a pronounced effect on hydrodynamics, patterns of erosion and deposition, and overall planform evolution in meandering rivers. Our research focuses on examining the interactions among three-dimensional flow structure, channel bed morphology, sediment transport, and large vegetation, particularly in large (bankfull widths greater than ~300 m) rivers to better understand how the effects of vegetation on river dynamics scale with channel dimension. Read more about our research findings in the following publications:
​
(https://www.sciencedirect.com/science/article/pii/S0169555X15301148)
​
Konsoer et al., 2016b. Three-dimensional flow structure and bed morphology in large elongate meander loops with different outer bank roughness characteristics. Water Resources Research.
(https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2016WR019040)
​
Konsoer et al., 2017. Length scales and statistical characteristics of outer bank roughness for large elongate meander bends: The influence of bank material properties, floodplain vegetation and flow inundation. Earth Surface Processes and Landforms.
