Parameter uncertainty and sensitivity analysis in sediment flux calculation

Abstract. This paper examines uncertainties in the calculation of annual sediment budgets at the outlet of rivers. Emphasis is put on the sensitivity of power-law rating curves to degradations of the available discharge-concentration data. The main purpose is to determine how predictions arising from usual or modified power laws resist to the infrequence of concentration data and to relative uncertainties affecting source data. This study identifies cases in which the error on the estimated sediment fluxes remains of the same order of magnitude or even inferior to these in source data, provided the number of concentration data is high enough. The exposed mathematical framework allows considering all limitations at once in further detailed investigations. It is applied here to bound the error on sediment budgets for the major French rivers to the sea.

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Flux of debris transported by ice at three Alaskan tidewater glaciers

Journal of Glaciology ◽

10.3189/s0022143000030586 ◽

1996 ◽

Vol 42 (140) ◽

pp. 123-135 ◽

Cited By ~ 2

Author(s):

Lewis E. Hunter ◽

Ross D. Powell ◽

Daniel E. Lawson

Keyword(s):

Sediment Flux ◽

Southeast Alaska ◽

Tidewater Glaciers ◽

Sediment Budgets ◽

Grounding Line ◽

Glacier Ice ◽

Order Of Magnitude ◽

Glacial Dynamics ◽

Glacier Flow ◽

The Stability

AbstractThe stability of a tidewater terminus is controlled by glacial dynamics, calving processes and sedimentary processes at the grounding line. An investigation of grounding-line sediment dynamics and morainal-bank sediment budgets in Glacier Bay, Alaska, U.S.A., has yielded data that enable us to determine the debris fluxes of Grand pacific, Margerie and Muir Glaciers. Debris flux ranges from 105 to 106 m3 a−1, one to two orders of magnitude lower than the glacifluvial sediment fluxes (106−107 m3 a−1). Combined, these fluxes represent the highest yields known for glacierized basins. Large debris fluxes reflect the combined effects of rapid glacier flow, driven by the maritime climate of southeast Alaska, and highly erodible bedrock. Englacial-debris distribution is affected by valley width and relief, both of which control the availability of sediment. The number of tributaries controls the distribution and volume of debris in englacial and supraglacial moraines. At the terminus, iceberg-rafting removes up to two orders of magnitude more sediment from the ice-proximal environment than is deposited by melt-out or is dumped during calving events. Rough estimates of the sediment flux by deforming beds suggests that soft-bed deformation may deliver up to an order of magnitude more sediment to the terminus than is released from within the glacier ice.

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Examining erosion in New Zealand over millennial timescales using in-situ 10Be and 14C

10.5194/egusphere-egu2020-9309 ◽

2020 ◽

Author(s):

Duna Roda-Boluda ◽

Taylor Schilgen ◽

Maarten Lupker ◽

Wittmann Hella ◽

Prancevic Jeff ◽

...

Keyword(s):

New Zealand ◽

Erosion Rate ◽

Sediment Flux ◽

Short Term ◽

Sediment Fluxes ◽

Landslide Activity ◽

Erosion Rates ◽

Order Of Magnitude

Landslides are the major erosional process in many orogens, and one of the most sensitive erosional process to tectonic and climatic perturbations. However, it remains extremely difficult to constrain long-term or past rates of landslide activity, and hence their contribution to long-term landscape evolution and catchment sediment fluxes, because the physical records of landsliding are often removed in <102 yrs. Here, we use the in-situ 10Be and in-situ 14C concentrations of recent landslide deposits and catchments from the Fiordland and the Southern Alps of New Zealand to: (a) estimate landslide frequencies over 103-104 yr timescales, which we compare against landslide inventories mapped from air photos (<102 yrs) to estimate changes in landslide activity, (b) quantify catchment-averaged erosion rates, and landslide&#8217;s contribution to those erosional fluxes, and (c) test whether paired 14C-10Be measurements can be used to trace erosional depth-provenance and identify transient erosion rate changes. We show that 10Be concentrations on landslide deposits can be used to estimate landslide recurrence intervals and frequency over 103 yr timescales, and that 14C/10Be ratios reflect the depth-provenance of sediment, and possibly transient changes in erosion rates. The comparison of our 10Be-based long-term landslide frequencies with short-term published inventories suggests that landslide frequencies have increased towards the present by up to an order of magnitude. We compare sediment fluxes inferred from these long- and short-term landslide inventories with sediment flux estimates derived from 10Be catchment-averaged erosion rates, which allows us to examine fluctuations in erosion rate estimates from 101 to 103 yrs timescales.&#160;

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Flux of debris transported by ice at three Alaskan tidewater glaciers

Journal of Glaciology ◽

10.1017/s0022143000030586 ◽

1996 ◽

Vol 42 (140) ◽

pp. 123-135 ◽

Cited By ~ 60

Author(s):

Lewis E. Hunter ◽

Ross D. Powell ◽

Daniel E. Lawson

Keyword(s):

Sediment Flux ◽

Southeast Alaska ◽

Tidewater Glaciers ◽

Sediment Budgets ◽

Grounding Line ◽

Glacier Ice ◽

Order Of Magnitude ◽

Glacial Dynamics ◽

Glacier Flow ◽

The Stability

AbstractThe stability of a tidewater terminus is controlled by glacial dynamics, calving processes and sedimentary processes at the grounding line. An investigation of grounding-line sediment dynamics and morainal-bank sediment budgets in Glacier Bay, Alaska, U.S.A., has yielded data that enable us to determine the debris fluxes of Grand pacific, Margerie and Muir Glaciers. Debris flux ranges from 105to 106m3a−1, one to two orders of magnitude lower than the glacifluvial sediment fluxes (106−107m3a−1). Combined, these fluxes represent the highest yields known for glacierized basins. Large debris fluxes reflect the combined effects of rapid glacier flow, driven by the maritime climate of southeast Alaska, and highly erodible bedrock. Englacial-debris distribution is affected by valley width and relief, both of which control the availability of sediment. The number of tributaries controls the distribution and volume of debris in englacial and supraglacial moraines. At the terminus, iceberg-rafting removes up to two orders of magnitude more sediment from the ice-proximal environment than is deposited by melt-out or is dumped during calving events. Rough estimates of the sediment flux by deforming beds suggests that soft-bed deformation may deliver up to an order of magnitude more sediment to the terminus than is released from within the glacier ice.

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SEDIMENT BUDGETS BASED ON THE MASS OF SILT AND CLAY ON INTERTIDAL FLAT ADJACENT TO RIVER MOUTH

Coastal Engineering Proceedings ◽

10.9753/icce.v32.sediment.82 ◽

2011 ◽

Vol 1 (32) ◽

pp. 82

Author(s):

Fumihiko Yamada ◽

Nobuhisa Kobayashi ◽

Yuichiro Shirakawa ◽

Yoshihiro Sakanishi

Keyword(s):

River Mouth ◽

Sediment Flux ◽

Intertidal Flat ◽

Transport Pathways ◽

Relative Significance ◽

Sediment Fluxes ◽

Fine Grained ◽

Sediment Budgets ◽

Flux Monitoring ◽

Large Discharge

Fine-grained sediment budgets based on the monthly bed level and net sediment flux monitoring during October 2006 to October 2007 are estimated to examine the relative significance of tides and river discharges on mud transport on an intertidal flat adjacent to a river mouth in the semi-closed sound. The intertidal flat accreted during normal discharge conditions mainly due to the alongshore sediment flux toward the river mouth. However, the flat eroded during large discharge conditions at the time of low tides. The offshore sediment transport during the large discharge was four times larger than that during the normal discharge. The spatial variations of tidal currents cause alongshore sediment fluxes toward the river mouth on the intertidal flat adjacent to the river mouth. The proposed fine-grained sediment budgets are useful to understand and assess the transport pathways for silt and clay on the intertidal flat.

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Energy Dissipation During Subglacial Abrasion at Nisqually Glacier, Washington, U.S.A.

Journal of Glaciology ◽

10.3189/s0022143000029865 ◽

1979 ◽

Vol 23 (89) ◽

pp. 233-246 ◽

Cited By ~ 6

Author(s):

Richard C. Metcalf

Keyword(s):

Energy Balance ◽

Suspended Sediment ◽

Water Flux ◽

Gravitational Energy ◽

Sediment Flux ◽

Normal Stresses ◽

Mount Rainier ◽

Suspended Sediment Flux ◽

Basal Sliding ◽

Order Of Magnitude

AbstractThis study examines the effect of subglacial abrasion on the basal sliding term of the gravitational energy balance of the dynamic, temperate Nisqually Glacier on Mount Rainier, Washington, U.S.A. Subglacial water flux is estimated as 3 × 107 m3 a–1 and suspended sediment flux as 3 × 107 kg a–1. Suspended-sediment flux is assumed to represent, within an order of magnitude, the annual mass eroded by subglacial abrasion.Subglacial abrasion involves both brittle fracture and plastic deformation. Field observations of bas-relief and grooved depression striations appear to have exact counterparts in rock mechanics experiments approximating subglacial velocities and normal stresses. Boulton's ([Cl974]) abrasion model and a new attritivity model proposed herein are shown to predict subglacial abrasion-rates within the limits of natural variability and the error range of measurements. The first crude gravitational energy balance for lower Nisqually Glacier (1.96 km2) is attempted and probably has only order-of-magnitude accuracy. The importance of subglacial abrasion in dissipating basal sliding energy at Nisqually Glacier is confirmed.

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Estimation of hepatitis B virus cccDNA persistence in chronic infection using within-host evolutionary rates

10.1101/2020.02.04.20020362 ◽

2020 ◽

Cited By ~ 3

Author(s):

Katrina A. Lythgoe ◽

Sheila F. Lumley ◽

Jane A. McKeating ◽

Philippa C. Matthews

Keyword(s):

Hepatitis B Virus ◽

Hepatitis B ◽

Chronic Infection ◽

Standard Of Care ◽

Evolutionary Rates ◽

Mathematical Framework ◽

Novel Approach ◽

B Virus ◽

Order Of Magnitude ◽

Progressive Liver Disease

AbstractHepatitis B virus (HBV) infection is a major global health problem with over 240 million infected individuals at risk of developing progressive liver disease and hepatocellular carcinoma. HBV is an enveloped DNA virus that establishes its genome as an episomal, covalently closed circular DNA (cccDNA) in the nucleus of infected hepatocytes. Currently available standard-of-care treatments for chronic hepatitis B (CHB) include nucleos(t)ide analogues (NA) that suppress HBV replication but do not target the cccDNA and hence rarely cure infection. There is considerable interest in determining the lifespan of cccDNA molecules to design and evaluate new curative treatments. We took a novel approach to this problem by developing a new mathematical framework to model changes in evolutionary rates during infection which, combined with previously determined within-host evolutionary rates of HBV, we used to determine the lifespan of cccDNA. We estimate that during HBe-antigen positive (HBeAgPOS) infection the cccDNA lifespan is 61 (36-236) days, whereas during the HBeAgNEG phase of infection it is only 26 (16-81) days. We found that cccDNA replicative capacity declined by an order of magnitude between HBeAgPOS and HBeAgNEG phases of infection. Our estimated lifespan of cccDNA is too short to explain the long durations of chronic infection observed in patients on NA treatment, suggesting that either a sub-population of long-lived hepatocytes harbouring cccDNA molecules persists during therapy, or that NA therapy does not suppress all viral replication. These results provide a greater understanding of the biology of the cccDNA reservoir and can aid the development of new curative therapeutic strategies for treating CHB.

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Impact of change in erosion rate and landscape steepness on hillslope and fluvial sediments grain size in the Feather River Basin (Sierra Nevada, California)

Earth Surface Dynamics Discussions ◽

10.5194/esurfd-2-1047-2014 ◽

2014 ◽

Vol 2 (2) ◽

pp. 1047-1092 ◽

Cited By ~ 1

Author(s):

M. Attal ◽

S. M. Mudd ◽

M. D. Hurst ◽

B. Weinman ◽

K. Yoo ◽

...

Keyword(s):

Grain Size ◽

River Basin ◽

Sierra Nevada ◽

Sediment Flux ◽

Fluvial Sediments ◽

Sediment Grain Size ◽

Erosion Rates ◽

Wide Range ◽

Feather River ◽

Order Of Magnitude

Abstract. The characteristics of the sediment transported by rivers (e.g., sediment flux, grain size distribution – GSD –) dictate whether rivers aggrade or erode their substrate. They also condition the architecture and properties of sedimentary successions in basins. In this study, we investigate the relationship between landscape steepness and the grain size of hillslope and fluvial sediments. The study area is located within the Feather River Basin in Northern California, and studied basins are underlain exclusively by tonalite lithology. Erosion rates in the study area vary over an order of magnitude, from > 250 mm ka−1 in the Feather River canyon to < 15 mm ka−1 on an adjacent low relief plateau. We find that the coarseness of hillslope sediment increases with increasing hillslope steepness and erosion rates. We hypothesize that, in our soil samples, the measured ten-fold increase in D50 and doubling of the amount of fragments larger than 1 mm when slope increases from 0.38 to 0.83 m m−1 is due to a decrease in the residence time of rock fragments, causing particles to be exposed for shorter periods of time to processes that can reduce grain size. For slopes in excess of 0.7 m m−1, landslides and scree cones supply much coarser sediment to rivers, with D50 and D84 more than one order of magnitude larger than in soils. In the tributary basins of the Feather River, a prominent break in slope developed in response to the rapid incision of the Feather River. Downstream of the break in slope, fluvial sediment grain size increases, due to an increase in flow competence (mostly driven by channel steepening) but also by a change in sediment source and in sediment dynamics: on the plateau upstream of the break in slope, rivers transport easily mobilised fine-grained sediment derived exclusively from soils. Downstream of the break in slope, mass wasting processes supply a wide range of grain sizes that rivers entrain selectively, depending on the competence of their flow. Our results also suggest that in this study site, hillslopes respond rapidly to an increase in the rate of base-level lowering compared to rivers.

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Fluvial sediment fluxes response to modern climate change and human activities in the Tibetan Plateau and its margins

10.5194/egusphere-egu21-130 ◽

2021 ◽

Author(s):

Dongfeng Li ◽

Xixi Lu ◽

Ting Zhang

Keyword(s):

Climate Change ◽

Water Resources ◽

Tibetan Plateau ◽

Air Temperature ◽

Human Activities ◽

Sediment Flux ◽

The Tibetan Plateau ◽

Fluvial Sediment ◽

Sediment Fluxes ◽

Cold Environments

Sediment flux in cold environments is a crucial proxy to link glacial, periglacial, and fluvial systems and highly relevant to hydropower operation, water quality, and the riverine carbon cycle. However, the long-term impacts of climate change and multiple human activities on sediment flux changes in cold environments remain insufficiently investigated due to the lack of monitoring and the complexity of the sediment cascade. Here we examine the multi-decadal changes in the in-situ observed fluvial sediment fluxes from two types of basins, namely, pristine basins and disturbed basins, in the Tibetan Plateau and its margins. The results show that the fluvial sediment fluxes in the pristine Tuotuohe headwater have substantially increased over the past three decades (i.e., a net increase of 135% from 1985&#8211;1997 to 1998&#8211;2017) due to the warming and wetting climate. We also quantify the relative impacts of air temperature and precipitation on the increases in the sediment fluxes with a novel attribution approach and finds that climate warming and intensified glacier-snow-permafrost melting is the primary cause of the increased sediment fluxes in the pristine cold environment (Tuotuohe headwater), with precipitation increase and its associated pluvial processes being the secondary driver. By contrast, the sediment fluxes in the downstream disturbed Jinsha River (southeastern margin of the Tibetan Plateau) exhibit a net increase of 42% from 1966-1984 to 1985-2010 mainly due to human activities such as deforestation and mineral extraction (contribution of 82%) and secondly because of climate change (contribution of 18%). Then the sediment fluxes dropped by 76% during the period of 2011-2015 because of the operations of six cascade reservoirs since 2010. In an expected warming and wetting climate for the region, we predict that the sediment fluxes in the pristine headwaters of the Tibetan Plateau will continue to increase throughout the 21st century, but the rising sediment fluxes from the Tibetan Plateau would be mostly trapped in its marginal reservoirs.Overall, this work has provided the sedimentary evidence of modern climate change through robust observational sediment flux data over multiple decades. It demonstrates that sediment fluxes in pristine cold environments are more sensitive to air temperature and thermal-driven geomorphic processes than to precipitation and pluvial-driven processes. It also provides a guide to assess the relative impacts of human activities and climate change on fluvial sediment flux changes and has significant implications for water resources stakeholders to better design and manage the hydropower dams in a changing climate. Such findings may also have implications for other cold environments such as the Arctic, Antarctic, and other high mountainous basins.Furthermore, this research is under the project of "Water and Sediment Fluxes Response to Climate Change in the Headwater Rivers of Asian Highlands" (supported by the IPCC and the Cuomo Foundation) and the project of "Sediment Load Responses to Climate Change in High Mountain Asia" (supported by the Ministry of Education of Singapore). Part of the results are also published in Li et al., 2018 Geomorphology, Li et al., 2020 Geophysical Research Letters, and Li et al., 2021 Water Resources Research.

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Sediment Budgets and Sediment Delivery Ratios in River Systems

Environmental Science ◽

10.1093/obo/9780199363445-0058 ◽

2016 ◽

Author(s):

Gary Brierly ◽

Jon Tunnicliffe

Keyword(s):

Landscape Connectivity ◽

Sediment Accumulation ◽

River Management ◽

Sediment Flux ◽

River Systems ◽

Catchment Scale ◽

Sediment Delivery ◽

Sediment Movement ◽

Sediment Budgets ◽

Continental Scale

The term sediment flux refers to sediment movement through landscapes. Analogous to “flux” in physics, i.e., the rate of flow of a property per unit area, sediment flux is the amount of sediment that flows through a cross-section of river per unit time. The magnitude of sediment flux is moderated by catchment processes such as sediment production (erosion), sediment accumulation (deposition) and intervening processes of sediment storage and reworking (transfer). Patterns and rates of sediment flux vary over a wide range of spatial and temporal scales, from grain to grain and landform scale analyses over near instantaneous timeframes through reach and catchment-scale analyses that are typically performed over decadal to millennial timescales to continental-scale appraisals over millions of years. Sediment movement is a key physical driver of natural environments. It exerts a critical influence upon the morphology, process regime, and evolutionary traits of landscapes. For example, as sediment budgets quantify sediment transport pathways, they can be used to analyze the critical factors that affect landscape development. Sediment flux exerts a critical influence upon the physical template (habitat distribution) of river systems. As such, it is a key consideration in river management and restoration. Analysis of source-to-sink relationships at the catchment scale (and associated sediment budgets) highlights controls upon sediment delivery and the influence of landscape connectivity. Emphasis here is placed upon valley floor processes, giving only partial attention to hillslope forms and processes or consideration of lakes, deltas, and nearshore marine environments. Textbooks and journals that present overviews of sediment flux in river systems are considered first. A brief overview of global scale sediment flux summarizes the movement of sediment from terrestrial areas to the ocean and the imprint of human activities. Most of this contribution focuses on catchment-scale sediment budgets, emphasizing variability in sediment sources (hillslope inputs and reworking on valley floors), the thorny question of scale relations, controls upon the sediment delivery ratio, and the influence of landscape connectivity. In many instances, disturbance events disrupt the sediment regime of a river, creating distinct pulses (or waves) that are transferred downstream by dispersion or migration processes. This is followed by an analysis of approaches to measurement of sediment flux, differentiated in relation to conventional field techniques, use of sediment fingerprinting, and the emergence of a range of remotely sensed technologies. The final sections of this article outline implications of human-induced alterations to sediment flux for river management. Appraisal of sediment disasters (impacts of dams, fine-grained sediment accumulation, and mining activities) is followed by an assessment of implications for river restoration.

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Single-station estimates of suspended sediment loads using sediment rating curves

Canadian Journal of Civil Engineering ◽

10.1139/l93-014 ◽

1993 ◽

Vol 20 (1) ◽

pp. 133-143 ◽

Cited By ~ 6

Author(s):

David Hansen ◽

Dale I. Bray

Keyword(s):

Suspended Sediment ◽

Sediment Concentration ◽

Ordinary Least Squares ◽

Least Squares Regression ◽

Concentration Data ◽

Data Set ◽

Sediment Loads ◽

Single Station ◽

Rating Curves ◽

River Cross Section

Sediment rating curves in conjunction with daily flow data have often been used to estimate the total mass of sediment flowing past a given river cross section over relatively long periods of time. Techniques are presented that seek to make the best use of limited noncontinuous suspended sediment concentration data to generate nine partial years of suspended sediment load by means of sediment rating curves for the Kennebecasis River, N.B. (drainage area of 1100 km2). Initially, the data were partitioned in an attempt to improve correlations between concentration and discharge. Such partitioning by season, month, periods of rising stage, and periods of falling stage did not uniformly improve correlations as compared with the correlations for nonpartitioned data. Various combinations of less well-known methods were then used, including a moving intercept method that makes greater use of point concentration observations in time, and correction factor methods for simple power-type relations as suggested by Ferguson and by Duan. In addition, the validity of some of the underlying assumptions for performing ordinary least-squares regression is examined for this data set. Finally, the effect of daily flow averaging on the computed load was examined and found to be small for this basin. Key words: suspended sediment, C–Q rating curves, flow averaging, washload estimates, statistical bias, regression estimates.

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