Abstract The Anthropocene is proposed as a new interval of geological time in which human influence on Earth and its record dominates over natural processes. A major challenge demarcating the that balance between human‐influenced processes varies spatial temporal scales owing to inherent variability both activities (as associated with culture modes development) drivers (e.g. tectonic activity sea level variation). Against this backdrop, we consider how geomorphology might contribute towards...

Abstract The Bolivian Andes flank one of Earth's major topographic features and dominate sediment input into the Amazon Basin. Millennial‐scale erosion rates dominant controls on patterns in this range are poorly known. To define these patterns, we present 48 rate estimates, derived from analysis situ 10 Be quartz‐bearing alluvium collected Upper Beni River basin. Erosion rates, corrected for non‐uniform distribution quartz sample basins, 0·04 mm a −1 to 1·35 thus integrate over 2 –10 4...

To predict erosion rates throughout the Andes, we conducted a multiple regression analysis of sediment discharge from 47 drainage basins in Bolivian Andes and various topographic, climatologic, geologic parameters. These mountainous are typically large (17–81,000 km2; $$\mathrm{mean}\,=11,000$$ km2), often have decades measurement data on daily water discharge, display an extraordinary range denudation (0.01–6.9 mm/yr), runoff (16–2700 local topographic relief (700–4300 m), yet underlying...

Rates of aggradation and infilling accommodation space along lowland channels in response to postglacial sea level rise should depend on sediment supply. The Strickland Fly rivers join at just 6 m above have experienced the same Holocene rise. Historically, has carried about 7 times load 1.4 water discharge as Fly. Therefore we hypothesize that floodplain be more developed consequently presently capturing proportionately less than River. We use mine‐derived elevated Pb Ag concentrations 111...

We investigated the processes of sediment exchange between Strickland River and its lowland floodplain, documenting (1) rates, textures, distributions accumulation, (2) temporal variations in these (3) remobilization by erosive processes, (4) whether net storage is significant over century timescales. used 210 Pb geochronology floodplain cores from 11 transects to measure deposition rates past ∼65 years, finding a decline 5.5 cm/a (0–10 m distance channel) 0.9 (∼400 m) ∼0.1 (>1 km). Rates...

ABSTRACT The ‘Anthropocene’, as used to describe the interval of recent Earth history during which humans have had an ‘overwhelming’ effect on system, is now being formally considered a possible new geological Epoch. Such time (possibly equivalent Pleistocene Epoch) requires both theoretical justification well empirical evidence preserved within record. Since record driven by geomorphological processes that produce terrestrial and near‐shore stratigraphy, geomorphology has be integral part...

ABSTRACT Meander bends of many large, sand‐bed meandering rivers are partitioned by chute channels that convey permanent flow, and co‐exist with the mainstem for decades. As a first step toward understanding dynamics morphodynamic implications these ‘bifurcate meander bends’, this study applied binary logistic regression analysis to determine whether it is possible predict initiation based on attributes bend character dynamics. Regression models developed Strickland River, Papua New Guinea,...

Abstract The evolution of meandering river floodplains is predominantly controlled by the interplay between overbank sedimentation and channel migration. resulting spatial heterogeneity in floodplain deposits leads to variability bank erodibility, which turn influences migration planform development. Despite potential significance these feedbacks, few studies have quantified their impact upon construction dynamic settings (e.g. locations characterized rapid high rates sedimentation). This...

Significance This paper is of fundamental interest to the millions residents living at downstream end this and other global river basins beset by industrial metals mining. Sediment-bound Hg has contaminated food webs San Francisco Bay-Delta, but dominant geographical sources ecosystems in similar are debated. Likewise, processes which delivered lowlands patterns its floodplain deposition poorly understood. research addresses a gap generic theory postmining fan evolution that enables...

Abstract The three‐dimensional flow field near the banks of alluvial channels is primary factor controlling rates bank erosion. Although submerged slump blocks and associated large‐scale roughness elements have both previously been proposed to divert away from bank, direct observations interaction between eroded material 3‐D are lacking. Here we use multibeam echo sounding, terrestrial laser scanning, acoustic Doppler current profiling quantify, for first time, influence on near‐bank field....

Although an inordinate fraction of the global sediment flux to ocean occurs in tropical mountainous river margins, little is known regarding sources and fate organic matter these systems. To address knowledge gaps, distribution composition sediments from Fly River delta‐clinoform were examined context source‐to‐sink study Papuan Continuum. The significant contrasts texture seabed measured across area coincided with stark concentration sedimentary matter. Coarser displayed significantly lower...

The highstanding islands of Oceania are recognized as a source significant particulate organic carbon delivered to nearshore marine environments. existing data on export in largely derived from small mountainous watersheds (<10,000 km 2 ) with little or no sediment storage capacity and located subtropical temperate regions. Fly‐Strickland fluvial dispersal system is the largest tropical has high yields, aged matter its suspended‐sediment load, lowland capacity. Fly River also very soil...

Abstract. Is anthropogenic soil erosion a sink or source of atmospheric carbon? The answer depends on factors beyond hillslope alone because the probable fate mobilized carbon evolves as it traverses fluvial system. transit path, residence times, and resulting mechanisms C-loss gain change significantly down-basin are currently difficult to predict soils erode floodplains evolve – this should be key focus future research.

Abstract Bifurcations are key geomorphological nodes in anabranching and braided fluvial channels, controlling local bed morphology, the routing of sediment water, ultimately defining stability their associated diffluence–confluence unit. Recently, numerical modelling bifurcations has focused on relationship between flow conditions partitioning bifurcate channels. Herein, we report field observations spanning September 2013 to July 2014 three‐dimensional structure, morphological change both...

Hydraulic gold mining in the Sierra Nevada, California (1853–1884) displaced ~1.1 billion m3 of sediment from upland placer gravels that were deposited along piedmont rivers below dams where floods can remobilize them. This study uses topographic and planimetric data detailed 1906 maps, 1999 photogrammetric data, pre- post-flood aerial photographs to document historic erosion deposition lower Yuba River due individual at reach scale. Differencing 3 × 3-m indicates substantial changes channel...

Floodplain sedimentation removes particles from fluvial transport and constructs stratigraphic records of flooding, biogeochemical sequestration other aspects the environmental history river basins—insight that is enhanced by accurate geochronology. The natural fallout radionuclide 210 Pb, often employed to date lacustrine marine sediments, has previously been used determine floodplain accumulation rates over decadal-to-century time scales using assumption both input concentration sediment...

Abstract This methods paper details the first attempt at monitoring bank erosion, flow and suspended sediment a site during flooding on Mekong River induced by passage of tropical cyclones. We deployed integrated mobile laser scanning (MLS) multibeam echo sounding (MBES), alongside acoustic Doppler current profiling (aDcp), to directly measure changes in river bed high (~0.05 m) spatial resolution, conjunction with measurements dynamics. outline methodological steps used collect process this...

The Sacramento River's flood-control system was conceived as a series of weirs and bypasses that routes floods out the leveed main channel into natural floodways engineered to drain directly bay delta. system, superimposed on geomorphic setting consisting geologic, sedimentary, tectonic controls, still relies keep low-lying communities dry during floods. However, Valley bypass exhibits widespread evidence impairment by sedimentation, especially at prehistoric loci alluvial splays. Episodic...

Recent synthesis of 10Be-derived denudation rates by [Willenbring et al. (2013)][1] suggests that the “flat” areas world, those with average slopes <∼100 m/km and representing ∼90% Earth’s land surface, have adequately high to produce most sediment