Eroding Cascadia—Sediment and solute transport and landscape denudation in western Oregon and northwestern California

2021 ◽  
Vol 133 (9-10) ◽  
pp. 1851-1874
Author(s):  
Jim E. O’Connor ◽  
Joseph F. Mangano ◽  
Daniel R. Wise ◽  
Joshua R. Roering
Keyword(s):  
Solute Transport ◽  
Volcanic Rocks ◽  
Suspended Load ◽  
Bed Load ◽  
Willamette River ◽  
Rock Types ◽  
Denudation Rates ◽  
Solute Fluxes ◽  
Basin Scale ◽  
Load Transport

Abstract Riverine measurements of sediment and solute transport give empirical basin-scale estimates of bed-load, suspended-sediment, and silicate-solute fluxes for 100,000 km2 of northwestern California and western Oregon. This spatially explicit sediment budget shows the multifaceted control of geology and physiography on the rates and processes of fluvial denudation. Bed-load transport is greatest for steep basins, particularly in areas underlain by the accreted Klamath terrane. Bed-load flux commonly decreases downstream as clasts convert to suspended load by breakage and attrition, particularly for softer rock types. Suspended load correlates strongly with lithology, basin slope, precipitation, and wildfire disturbance. It is highest in steep regions of soft rocks, and our estimates suggest that much of the suspended load is derived from bed-load comminution. Dissolution, measured by basin-scale silicate-solute yield, constitutes a third of regional landscape denudation. Solute yield correlates with precipitation and is proportionally greatest in low-gradient and wet basins and for high parts of the Cascade Range, where undissected Quaternary volcanic rocks soak in 2–3 m of annual precipitation. Combined, these estimates provide basin-scale erosion rates ranging from ∼50 t · km−2 · yr−1 (approximately equivalent to 0.02 mm · yr−1) for low-gradient basins such as the Willamette River to ~500 t · km−2 · yr−1 (∼0.2 mm · yr−1) for steep coastal drainages. The denudation rates determined here from modern measurements are less than those estimated by longer-term geologic assessments, suggesting episodic disturbances such as fire, flood, seismic shaking, and climate change significantly add to long-term landscape denudation.

scholarly journals Regression analysis between sediment transport rates and stream discharge for the Nestos River, Greece

2013 ◽  
Vol 14 (3) ◽  
pp. 362-370
Keyword(s):  
Sediment Transport ◽  
Suspended Load ◽  
Bed Load ◽  
Regression Curve ◽  
Degree Polynomial ◽  
Stream Discharge ◽  
Nestos River ◽  
Polynomial Curve ◽  
Load Transport ◽  
Bed Load Transport

Systematic measurements of sediment transport rates and water discharge were conducted in the Nestos River (Greece), at a place located between the outlet of Nestos River basin and the river delta. This basin area is about 838 km2 and lies downstream of the Platanovrysi Dam. Separate measurements of bed load transport and suspended load transport were performed at certain cross sections of the Nestos River. In this study, relationships between sediment transport rates and stream discharge for the Nestos River are presented. A nonlinear regression curve (4th degree polynomial curve; r2 equals 0.62) between bed load transport rates and stream discharge, on the basis of 63 measurements, was developed. In addition, a nonlinear regression curve (5th degree polynomial curve; r2 equals 0.95) between suspended load transport rates and stream discharge, on the basis of 65 measurements, was developed. The relatively high r2 values indicate that both bed load transport rates and, especially, suspended load transport rates can be predicted as a function of the stream discharge in the Nestos River. However, the reliability of the regression equations would have been higher if more measured data were available.

scholarly journals Analisa Angkutan Sedimen Pada Hulu Bendung Aepodu Kabupaten Konawe Selatan

2021 ◽  
Vol 2 (1) ◽  
pp. 1-7
Author(s):  
Ramadhan Hidayat Putra ◽  
Amad Syarif Syukri ◽  
Catrin Sudarjat ◽  
Vickky Anggara Ilham
Keyword(s):  
Sediment Transport ◽  
River Flow ◽  
Suspended Load ◽  
Bedload Transport ◽  
Bed Load ◽  
Average Flow ◽  
Load Transport ◽  
Bed Load Transport ◽  
Transport Analysis

Research on Aepodu Weir Sediment Transport Analysis in South Konawe District, based on observations in the field, Aepodu Weir hasa sediment buildup that has now exceeded the height of the weirlight house. The purpose of the study was to analyze the magnitudeof Aepodu river flow and to analyze the amount of sedimenttransport that occurred in the Aepodu dam. The method used todetermine the amount of bed load transport uses stchoklitscht, whilefor transporting suspended load using forcheimer.The results of the analysis of the average flow of the Aepodu riverwere 3,604 m3/ second. Sediment transport that occurs in Aepoduweir is Bedload transport (Qb) of 291625.771 tons / year, andsuspended load transport (Qs) of 16972,423 tons / year, so that thetotal sediment transport (QT) is 308598,194 tons / year.

The ratio of mechanical to chemical denudation in alluvial systems, derived from geochemical mass balance

1993 ◽  
Vol 84 (1) ◽  
pp. 73-78 ◽  
Author(s):  
A. D. Stewart
Keyword(s):  
Mass Balance ◽  
Chemical Weathering ◽  
Amazon Basin ◽  
Source Area ◽  
Large River ◽  
Suspended Load ◽  
Bed Load ◽  
Load Transport ◽  
Bed Load Transport ◽  
Dissolved Load

ABSTRACTMass balance equations are derived which link the ratios Ts/ (suspended load/dissolved load from chemical weathering) and Tb/Ts (bed load/suspended load), with any two geochemical components present in the source rock and the alluvial system. If the dissolved load is unknown the ratios can be estimated from the relatively insoluble silica and alumina. The ratio Ts/, which for large river basins depends on climate and relief, can thus potentially be determined from ancient alluvial sequences.The equations help define the source composition of a group of 13 modern rivers for which Ts, and alluvial geochemistry are known. These rivers together drain 27% of the continental surface. For a source area with the average continental sandstone to shale ratio of 0·6 the observed average value of Ts/ is obtained when limestone, sandstone and shale are present in the proportions 6·7:21·6:35·7. The figure of 64% sediment in the source area is very similar to the 66% determined by Blatt and Jones (1975) from geological maps of the continents. The equations also show that average bed load transport rate into these 13 basins is about 27% of total transport, and into the Amazon basin about 37%. Bed load transport rates out of the basins, into the sea, are relatively very small.

Effect of Impoundment and Diversion on the Sediment Budget and Nearshore Sedimentation of Southern Indian Lake

1984 ◽  
Vol 41 (4) ◽  
pp. 567-578 ◽  
Author(s):  
R. E. Hecky ◽  
G. K. McCullough
Keyword(s):  
Fine Particles ◽  
Suspended Load ◽  
Constituent Particle ◽  
Shoreline Erosion ◽  
Bed Load ◽  
Particle Sizes ◽  
Fine Silt ◽  
Load Transport ◽  
Bed Load Transport ◽  
Clay Aggregates

Shoreline erosion added an annual average of 4 × 106 t of mineral sediment per year to Southern Indian Lake (postimpoundment area, 2391 km2) during the first 3 yr of impoundment. This erosion increased sedimentary input to the lake by a factor of 20. The lake retained 90% of this eroded material within its basin, and 80–90% of the retained material was deposited nearshore. Despite the production of extremely fine constituent particle sizes, eroding shorelines generated predominantly large clay aggregates, initially transported offshore as bed load. During bed load transport, abrasion of clay aggregates produced fine particles that became suspended. Over 80% of the suspended load is lost to outflows from the lake because the suspended load is primarily fine silt and clay-sized particles, most of which do not settle even under winter ice cover. The extensive nearshore clay aggregate deposits are temporary, and net deposition in these areas will change to net erosion when input of sediment from eroding shorelines ceases. The effects of shoreline erosion on the lake's sediment regime will persist for decades.

scholarly journals Variability of fluvial transport of the upper Wieprz river

2008 ◽  
Vol 39 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Sylwia Stępniewska ◽  
Krzysztof Stępniewski
Keyword(s):  
Extreme Values ◽  
Hydrological Regime ◽  
Suspended Load ◽  
Bed Load ◽  
Annual Average ◽  
Monthly Average ◽  
Denudation Rates ◽  
Fluvial Transport ◽  
Dissolved Load

Variability of fluvial transport of the upper Wieprz river This paper shows variability of fluvial transport of the Wieprz river. The catchment of the upper Wieprz river to profile at Guciów located in Central Roztocze Region. In Wieprz during the hydrological years 1996-2006 average annual flow is 1.32 m3·s-1, which correspond to the outflow - 41.5 Mm3·a-1. Extreme values of the flows varied from 0.5 m3·s-1 to 13,1 m3·s-1. Outflow the Wieprz river has feature for the snow-rainy hydrological regime. During the study the annual average suspended load amounted 737 Mg. The annual average dissolved load amounted 10 343 Mg. The bed load estimated for less than 10% of the dissolved load and 1% of the suspended load. The monthly average suspended load and dissolved load were least in the November and were highest in the April. During the period of researches, the average mechanical denudation rates 2.4 Mg·km-2·a-1. Chemical denudation rates were much higher - 36.1 Mg·km-2·a-1. Their differentiation are similar in other regions of Poland.

scholarly journals A Sediment Transport Model for Straight Alluvial Channels

1976 ◽  
Vol 7 (5) ◽  
pp. 293-306 ◽  
Author(s):  
Frank Engelund ◽  
Jørgen Fredsøe
Keyword(s):  
Sediment Transport ◽  
Transport Model ◽  
Suspended Load ◽  
Empirical Models ◽  
Bed Load ◽  
Alluvial Channels ◽  
Physical Processes ◽  
Sediment Transport Model ◽  
Load Transport ◽  
Bed Load Transport

The paper presents a simple mathematical model for sediment transport in straight alluvial channels. The model, which is based on physical ideas related to those introduced by Bagnold (1954), was originally developed in two steps, the first describing the bed load transport (Engelund 1975) and the second accounting for the suspended load (Fredsøe and Engelund 1976). The model is assumed to have two advantages as compared with empirical models, first it is based on a description of physical processes, secondly it gives some information about the quantity and size of the sand particles in suspension and the bed particles.

Rock denudation rates and organic carbon exports along a latitudinal gradient in the Hudson, James, and Ungava bays watershed

2012 ◽  
Vol 49 (6) ◽  
pp. 742-757 ◽  
Author(s):  
Eric Rosa ◽  
Jérôme Gaillardet ◽  
Claude Hillaire-Marcel ◽  
Jean-François Hélie ◽  
Louis-Filip Richard
Keyword(s):  
Organic Carbon ◽  
Latitudinal Gradient ◽  
Major Ions ◽  
Volcanic Rocks ◽  
Canadian Shield ◽  
Denudation Rates ◽  
Major Cation ◽  
Major Cations ◽  
Basin Scale ◽  
The Relationship

This study documents chemical denudation rates (CDR) in the Canadian Shield and Interior Platform. It focuses on the dissolved chemistry of rivers flowing into the Hudson, James, and Ungava bays (HJUB). Major ions, strontium, neodymium, and dissolved organic carbon (DOC) concentrations were monitored in four rivers (Koksoak, Great Whale, La Grande, and Nelson). Six other rivers flowing into the HJUB were sampled during baseflow and snowmelt conditions. The rivers of the Canadian Shield exhibit major cation concentrations ranging between 62 and 360 µmol/L, [Nd] of 0.57–4.72 nmol/L, and variable [DOC] of 241–1777 µmol/L. In comparison, the Nelson River (Interior Platform) shows higher major cation concentrations (1200–2276 µmol/L), lower [Nd] (0.14–0.45 nmol/L), and intermediate [DOC] (753–928 µmol/L). Altogether, the studied rivers export 8 × 106 t/year of dissolved major cations and 50 t/year of dissolved Nd towards the HJUB. Basin-scale rock denudation rates (RDR) range from 1.0 to 5.3 t·km–2·year–1 and are essentially controlled by lithology, as illustrated by the relationship established between RDR and the proportion of sedimentary and volcanic rocks (%S + %V) within the basins: RDR = 0.08(%S + %V) + 0.9. In contrast, dissolved Nd exports (and likely other insoluble elements) seem to be dependent upon organic matter leaching, as illustrated by the empirical coupling between Nd and DOC exports. These fluxes decrease northwards, likely in response to the hydroclimatic gradient. The CDR evaluated within the Canadian Shield are among the lowest on the planet, and the alkalinity generated by rock weathering remains small with respect to DOC exports.

scholarly journals The morphodynamics of a swash event on an erodible beach

2014 ◽  
Vol 762 ◽  
pp. 110-140 ◽  
Author(s):  
Fangfang Zhu ◽  
Nicholas Dodd
Keyword(s):  
Solitary Wave ◽  
Evolution Equations ◽  
Suspended Load ◽  
Bed Load ◽  
Advection Equation ◽  
Sedimentary Petrology ◽  
Load Transport ◽  
Bed Load Transport ◽  
Bed Changes ◽  
First Time

AbstractA high-accuracy numerical solution, coupling one-dimensional shallow water and bed-evolution equations, with, for the first time, a suspended sediment advection equation, thereby including bed and/or suspended load, is used to examine two swash events on an initially plane erodible beach: the event of Peregrine & Williams (J. Fluid Mech., vol. 440, 2001, pp. 391–399) and that of a solitary wave approaching the beach. Equations are solved by the method of characteristics, and the numerical model is verified. Full coupling of suspended load to beach change for Peregrine & Williams (J. Fluid Mech., vol. 440, 2001, pp. 391–399) yields only slightly altered swash flows, depending on beach mobility and sediment response time; a series of similar final beach change patterns results for different beach mobilities. Suspended- and bed-load transport have distinct morphodynamical signatures. For the solitary wave a backwash bore is created (Hibberd & Peregrine, J. Fluid Mech., vol. 95, 1979, pp. 323–345). This morphodynamical bore propagates offshore initially, and leads to the creation of a beach bed step (Larson & Sunamura, J. Sedimentary Petrology, vol. 63, 1993, pp. 495–500), primarily due to bed-load transport. Its height is directly related to bed-load mobility, and also depends strongly on the bed friction coefficient. The shock dynamics of this bed step is explained and illustrated. Bed- and suspended-load mobilities are quantified using field data, and an attempt is made to relate predictions to measurements of single swash events on a natural beach. Average predicted bed change magnitudes across the swash are of the order of 2 mm, with maximum bed changes of up to approximately 10 cm at the bed step.

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