Abstract Our objective is to understand general causes of different river channel patterns. In this paper we compare an empirical stream power‐based classification and a physics‐based bar pattern predictor. We present careful selection data from the literature that contains rivers with discharge median bed particle size ranging over several orders magnitude various patterns types, but no obvious eroding or aggrading tendency. Empirically continuum found for increasing specific power, here...

ABSTRACT Channel fills are common elements of Holocene river systems and older fluvial sequences, but surprisingly little is known about formation their sedimentary build‐up. Abandoned channels result from channel shifting processes at various scales, including meander cutoff channel‐belt avulsion. Channel‐fill sequences importance as containers palaeoenvironmental proxy‐records, can be used to reconstruct palaeochannel dynamics derive palaeoflood records, contain materials that allow dating...

ABSTRACT River bifurcations are critical but poorly understood elements of many geomorphological systems. They integral alluvial fans, braided rivers, fluvial lowland plains, and deltas control the partitioning water sediment through these Bifurcations commonly unstable their lifespan varies greatly. In rivers bars channels migrate, split merge at annual or shorter timescales, thereby creating abandoning bifurcations. This behaviour has been studied mainly by geomorphologists fluid...

Abstract Predicting debris flow runout is of major importance for hazard mitigation. Apart from topography and volume, distance area depends on composition rheology, but how poorly understood. We experimentally investigated effects runout, depositional mechanisms, deposit geometry. The small‐scale experimental flows were largely similar to natural in terms behavior, morphology, grain size sorting, channel width‐depth ratio, runout. Deposit geometry (lobe thickness width) our determined by...

[1] Braided rivers have complicated and dynamic bar patterns, which are challenging to fully understand predict both qualitatively quantitatively. Linear theory ignores nonlinear processes that dominate developed bars, whereas natural river patterns determined by the combined effects of boundary conditions, initial conditions such as planimetric forcing fixed banks physical processes. Here we determine capability a state-of-the-art physics-based morphological model reproduce morphology...

At river bifurcations, water and sediment are divided over two branches. The dynamics of the bifurcation determine long‐term evolution (centuries) downstream branches, potentially leading to avulsion, but poorly understood. can only be studied by one‐dimensional models because computational costs. For such models, a relation describing division is necessary, few relations available these remain tested so far. We study morphodynamics on timescale decades centuries idealized three‐dimensional...

Rivers self-organize their pattern/planform through feedbacks between bars, channels, floodplain and vegetation, which emerge as a result of the basic spatial sorting process wash load sediment bed sediment. The balance formation destruction determines width pattern channels. Floodplain structure affects style rate channel avulsion once aggradation takes place. Downstream fining fines in pores provide ‘template’ or boundary conditions, from at smaller scales leads to distinct patterns. Bar...

This paper summarizes state‐of‐the‐art models for water flow and sediment transport suggests implications the grain size distribution, process, delta formation. The velocity in Martian outflow channels is commonly calculated from Manning equation, which dimensionally incorrect masks large uncertainty of reconstructed velocity. More modern friction predictors based on surface distribution are tested 190 rivers Earth including moderately catastrophic events. a factor 3–4. assumed to amount 40%...

Braided rivers are relatively simple to produce in the laboratory, whereas dynamic meandering have not been sustained beyond initial bend formation. Meandering is theoretically explained by instability growing from planimetric perturbation, which convects downstream. In this study, we experimentally tested importance of upstream perturbation and chute cutoff development evolution dynamics a channel pattern. The straight had transversely moving inlet point silt‐sized silica flour was added...

[1] Granular materials avalanche when a static angle of repose is exceeded and freeze at dynamic repose. Such avalanches occur subaerially on steep hillslopes wind dunes subaqueously the lee side deltas. Until now it has been assumed that angles are independent gravitational acceleration. The objective this work to experimentally determine whether depend gravity. In 33 parabolic flights in well-controlled research aircraft we recorded avalanching granular rotating drums effective...

Incipient motion of particles on a river bed can, in principle, be understood and predicted from balance the forces acting particles. On natural exposure to flow is variable. The effect initiation motion, including case deep embedding, studied this paper. So far, turbulence‐induced lifting force has been derived exclusively examinations surface flow. understanding destabilization processes riverbed improved when vertical pressure gradients upper sediment layer are included. This particularly...

Abstract Dynamic interaction between river morphodynamics and vegetation affects channel patterns populations of riparian species. A range numerical models exists to investigate the morphodynamics. However, many these oversimplify either or dynamics, which hampers development predictive for management. We have developed a model coupling advanced dynamic vegetation, is innovative because it includes ecological processes progressing characteristics as opposed commonly used static without...

Research Article| April 01, 2014 Bank pull or bar push: What drives scroll-bar formation in meandering rivers? Wietse I. van de Lageweg; Lageweg Faculty of Geosciences, Department Physical Geography, Utrecht University, P.O. Box 80115, 3508 TC Utrecht, Netherlands Search for other works by this author on: GSW Google Scholar Wout M. Dijk; Dijk *Current address: Durham South Road, DH1 3LE, UK. Anne W. Baar; Baar Jantien Rutten; Rutten Maarten G. Kleinhans † †E-mail: M.G.Kleinhans@uu.nl....

Abstract Fan deltas are excellent recorders of fan‐building processes because their high sedimentation rate, particularly in tectonically active settings. Although previous research focuses mainly on allogenic controls, there is clear evidence for autogenically produced storage and release sediment by flume numerical modelling that demands further definition characteristics significance forced facies stratigraphy. Analogue experiments were performed fan with constant extrinsic variables...

Strong feedbacks exist between channel dynamics, floodplain development, and riparian vegetation. Earlier experimental studies showed how uniformly distributed vegetation causes a shift from braided to single‐thread river because stabilizes the banks focuses discharge off floodplains into channels. These experiments tested anemochorously vegetation, i.e., by wind, whereas many species in nature are also hydrochorously, flowing water. The objective of this study is test experimentally what...

ABSTRACT There is a paucity of data and insight in the mechanisms of, controls on flow separation recirculation at natural sharply‐curved river bends. Herein we report successful laboratory experiments that elucidate structure one constant‐width bend second with an outer‐bank widening. The were performed both flat immobile gravel bed mobile sand dominant bedload sediment transport. In bed, zone mainly horizontal (vertical rotational axis) formed inner bank did not contain detectable...

Abstract Morphodynamics in sand‐bed braided rivers are associated with simultaneous evolution of mid‐channel bars and channels on the braidplain. Bifurcations around key elements that divide discharge sediment. This, turn, may control connected branches, effects propagating to both upstream downstream bifurcations. Recent works bifurcation stability development hypothesize major roles secondary flow gradient advantage. However, this has not been tested for channel networks within a fully...

Abstract Bifurcating rivers shape natural landscapes by distributing water and sediments on fluvial plains in deltas. Symmetrical bifurcations were often found to be unstable so that one branch downstream of the bifurcation enlarged while other dwindled. A unified theory able predict stability both gravel bed sand is still lacking. Here we develop a new for entire range rivers. The indicates opposite behavior rivers: symmetrical are inherently stable intermediate Shields stresses but low...

Cohesive floodplain sediment and vegetation are both thought to cause meandering river patterns. Our aims compare the isolated combined effects of mud on planform morphodynamics in setting intermediate-sized valley rivers. We use a numerical model for century-scale simulation flow, transport morphology coupled with riparian settlement, growth mortality as functions species traits which flow resistance depends. Mud fluxes were predicted by excess shear stress relations combination active...

Abstract Alluvial fans develop their semi‐conical shape by quasi‐cyclic avulsions of geomorphologically active sector from a fixed fan apex. On debris‐flow fans, these are poorly understood, partly because physical scale experiments on the formation have been limited largely to turbidite and fluvial deltas. In this study, were experimentally created under constant extrinsic forcing, autogenic sequences backfilling, avulsion channelization observed. Backfilling, gradual processes that...