Chute cutoff-driven abandonment and sedimentation of meander bends along a fine-grained, non-vegetated, ephemeral river on the Bolivian Altiplano

Abstract

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Grain-size variability of point-bar deposits from a fine-grained dryland river terminus, Southern Altiplano, Bolivia

“…The Río Colorado is characterised by seasonal activation and downstream reduction in cross-section area due to the coupled effects of low precipitation, strong evapo-transpiration and infiltration (Donselaar et al, 2013;Li et al, 2014a). Previous studies in this river terminus system have revealed prominent splay morphodynamics and sediment dispersal patterns (Li et al, 2014a(Li et al, , 2019(Li et al, , 2020Li and Bristow, 2015;van Toorenenburg et al, 2018). Lowfrequency but high-magnitude floods have impacted considerably on the geomorphology and sedimentology of the river terminus, in particular in the distal part and floodplain of the river terminus due to significant overbank flooding (Li et al, 2018(Li et al, , 2019.…”

Digital Elevation Models for topographic characterisation and flood flow modelling along low-gradient, terminal dryland rivers: A comparison of spaceborne datasets for the Río Colorado, Bolivia

“…1B-C). Previous studies have integrated remote sensing imagery and field observations in investigations of the channel-floodplain morphodynamics of the middle reaches and the fan-shaped lower reaches approaching the terminus (Donselaar et al, 2013;Li et al, 2014aLi et al, , b, 2015Li et al, , 2018Li et al, , 2019Li et al, , 2020aLi and Bristow, 2015;van Toorenenburg et al, 2018). These studies have shown that the lower reaches of the main (trunk) channel are characterised by a prominent downstream decrease in cross-sectional area (Fig.…”

“…Sparsely or non-vegetated dryland river systems are receiving increasing research attention since they provide excellent modern analogues for the study of ancient (especially prevegetation) rock records and extraterrestrial surface environments (e.g. Grotzinger et al, 2015;Dietrich et al, 2017;Li et al, 2014aLi et al, , 2020aJacobsen and Burr, 2016;Ielpi, 2018;Ielpi and Lapôtre, 2019), and also may have significance for the management of ecosystem services and flood hazards in otherwise moisture-stressed settings (Tooth, 2013;Li et al, 2018). Many low-gradient dryland rivers are terminal systems that are characterised by significant downstream decreases in cross-sectional areas and sediment transport capacity, with defined channels commonly ending on channelless plains (floodouts), in wetlands, or at playa margins (Tooth, 1999a;Tooth and McCarthy, 2007;Ralph and Hesse, 2010).…”

“…Such interactions can have a profound influence on topographic development and flood flow dynamics, including natural levee breaching, crevasse splay development, chute cutoffs, and avulsion (e.g. Tooth, 2005;Li et al, 2014aLi et al, , 2020aLi and Bristow, 2015;Jarihani et al, 2015aJarihani et al, , 2015b, and can also lead to the formation of less well-documented features such as topographic lobes, reforming channels, and erosion cells (Tooth, 1999a, b;Tooth et al, 2002Tooth et al, , 2014Li et al, 2019). In these lowrelief settings, formation of such geomorphological features to a large extent is driven by subtle variations in local gradient, as this influences the distribution and rate of energy expenditure by flowing water and thus erosional and depositional patterns.…”

Past, present and future of a meandering river in the Bolivian Amazon basin

“…Bend development and sinuosity growth are limited by the occurrence of cutoffs (Van Dijk, 2013). Previous studies have demonstrated that neck cutoffs heavily influence the development of meandering rivers in terms of planform shape, hydraulics and sedimentology, both in the short and long term (Camporeale et al, 2008; Li et al, 2020; Schwenk & Foufoula‐Georgiou, 2016).…”