scholarly journals Re-suspension of bed sediment in a small stream – results from two flushing experiments

2013 ◽  
Vol 10 (10) ◽  
pp. 12077-12104 ◽  
Author(s):  
A. Eder ◽  
M. Exner-Kittridge ◽  
P. Strauss ◽  
G. Blöschl
Keyword(s):  
Sediment Load ◽  
Free Water ◽  
High Temporal Resolution ◽  
Small Stream ◽  
Bed Sediments ◽  
Small Watersheds ◽  
Wave Celerity ◽  
Streambed Sediments ◽  
Total Sediment ◽  
Stream Bed

Abstract. Streams draining small watersheds often exhibit multiple peaking sedigraphs associated with single peaking hydrographs. The process reasons of the multiple sediment peaks are not fully understood but they may be related to the activation of different sediment sources such as the streambed itself where deposited sediments from previous events may be available for resuspension. To understand resuspension of stream bed sediments at the reach scale we artificially flooded the small stream of the HOAL Petzenkirchen catchment in Austria by pumping sediment-free water into the stream. Two short floods were produced and flow, sediment and bromide concentrations were measured at three sites with high temporal resolution. Hydrologically, the two flood events were almost identical. The peak flows decreased from 57 to 7.9 L s−1 and the flow volumes decreased from 17 to 11.3 m3 along the 590 m reach of the stream. However, a considerably smaller sediment load was resuspended and transported during the second flood due to depletion of stream bed sediments. The exception was the middle section of the stream where more sediment was transported during the second flood event which can be explained by differences between flow velocity and wave celerity and the resulting displacement of sediments within the stream. The results indicate that the first peak of the sedigraphs of natural events in this stream is indeed caused by the resuspension of streambed sediments, accounting for up to six percent of the total sediment load depending on total flow volume.

scholarly journals Re-suspension of bed sediment in a small stream – results from two flushing experiments

2014 ◽  
Vol 18 (3) ◽  
pp. 1043-1052 ◽  
Author(s):  
A. Eder ◽  
M. Exner-Kittridge ◽  
P. Strauss ◽  
G. Blöschl
Keyword(s):  
Sediment Load ◽  
Free Water ◽  
High Temporal Resolution ◽  
Sediment Sources ◽  
Small Stream ◽  
Bed Sediments ◽  
Small Watersheds ◽  
Wave Celerity ◽  
Total Sediment ◽  
Stream Bed

Abstract. Streams draining small watersheds often exhibit multiple peaking sedigraphs associated with single peaking hydrographs. The process reasons of the multiple sediment peaks are not fully understood but they may be related to the activation of different sediment sources such as the stream bed itself, where deposited sediments from previous events may be available for resuspension. To understand resuspension of stream bed sediments at the reach scale we artificially flooded the small stream of the HOAL Petzenkirchen catchment in Austria by pumping sediment-free water into the stream. Two short floods were produced and flow, sediment and bromide concentrations were measured at three sites with high temporal resolution. Hydrologically, the two flood events were almost identical. The peak flows decreased from 57 to 7.9 L s−1 and the flow volumes decreased from 17 to 11.3 m2 along the 590 m reach of the stream. However, a considerably smaller sediment load was resuspended and transported during the second flood due to depletion of stream bed sediments. The exception was the middle section of the stream, where more sediment was transported during the second flood event which can be explained by differences between flow velocity and wave celerity and the resulting displacement of sediments within the stream. The results indicate that the first peak of the sedigraphs of natural events in this stream is indeed caused by the resuspension of stream bed sediments, accounting for up to six percent of the total sediment load depending on total flow volume.

The Total Sediment Load of Streams

1958 ◽  
Vol 84 (1) ◽  
pp. 1-36 ◽  
Author(s):  
Emmett M. Laursen
Keyword(s):  
Sediment Load ◽  
Total Sediment

A review on share of river bank erosion to the total sediment load with increasing catchment size

2021 ◽  
Author(s):  
Ghulam Abbas ◽  
Seifeddine Jomaa ◽  
Michael Rode
Keyword(s):  
Sediment Load ◽  
Bank Erosion ◽  
Surface Erosion ◽  
Sediment Sources ◽  
Catchment Scale ◽  
River Bank ◽  
River Bank Erosion ◽  
Wide Range ◽  
Catchment Size ◽  
Total Sediment

<p>Information on the share of river bank erosion to the total sediment load at catchment scale by using the fingerprinting approach is important to address our knowledge of erosion processes to better target soil erosion control measures. In particular, river bank erosion is affected by many factors such as spatial and temporal variables and is difficult to quantify the relationship of the share of bank erosion to catchment size and upland erosion rate without extensive fieldwork and data analysis. Potential tracers including geochemical, fallout radionuclides, bulk and compound-specific stable isotopes, and magnetic properties have been used, often in combination with sediment source apportionment. In this worldwide review, the global dataset for percent share of river bank and surface erosion using fingerprinting approach was collected to establish the significance of catchment size and other physical controls on river bank erosion. Google Scholar and Web of Science were used to review research articles that included river bank/subsurface as one of the sediment sources in the study areas. This database showed that the UK (n = 84), USA (n = 14) and Brazil (n = 10) had the highest number of catchments, followed by Iran (n = 4), Southern Zambia (n = 1), Australia (n = 1), Spain (n = 1), Mongolia (n = 1) and Burkina Faso (n = 1) ranging in size from 0.31 to 15000 km<sup>2</sup>, predominately agriculture. Based on published studies, there is a clear shift of sediment sources from surface erosion to river bank erosion with increasing catchment size. The results show the wide range of relative contributions of surface and river bank sources to the catchment sediment yield around the globe. There are a number of catchments with river bank contribution exceeding 25% and surface contribution exceeding 90% of total sediment loss. This diversity highlights the many factors that influence river bank erosion. In addition to the wide range, sediment source contribution in the range 1-25% from river bank is generally representative around the World. We recommend that long term monitoring of sediment load and surface and river bank sources at nested sites within a catchment are indispensable. Furthermore, limited information on the share of sources often makes it difficult to target mitigation measures reducing sediment loads at the catchment scale.</p><p><strong>Keywords: </strong>Sediment load, catchment size, fingerprinting approach, river bank share</p>

Stream-bed armouring under known conditions of upstream sediment input

1984 ◽  
Vol 21 (9) ◽  
pp. 1061-1066 ◽  
Author(s):  
Eric J. Schiller ◽  
A. Charles Rowney
Keyword(s):  
Particle Size ◽  
Sediment Load ◽  
Experimental Tests ◽  
Direct Influence ◽  
Sediment Sources ◽  
Characteristic Parameters ◽  
Bed Forms ◽  
Sediment Input ◽  
Bed Material ◽  
Stream Bed

Experiments were conducted to assess ways in which an imposed sediment load can affect the formation and final nature of an armoured bed. A flume loaded with a quartz aggregate of known composition was subjected to various sediment-laden flows of water to produce armoured beds. Characteristic parameters of the armoured beds were then compared.In general, it was found that the final armoured bed can be significantly altered by an imposed sediment load. As the size of the input sediment increased, the amount of bed material that was eroded, the resulting particle size of the bed, and the total roughness of the bed all decreased. The formation of bed forms was very important in this process. The trends observed in these experimental tests indicate that the presence or absence of upstream sediment sources has a direct influence on the resulting armoured layer.

Uranium Tailings Acidification and Subsurface Contaminant Migration in a Sand Aquifer

1984 ◽  
Vol 19 (2) ◽  
pp. 55-89 ◽  
Author(s):  
N.M. Dubrovsky ◽  
K.A. Morin ◽  
J.A. Cherry ◽  
D.J.A. Smyth
Keyword(s):  
Heavy Metals ◽  
Vadose Zone ◽  
Inner Core ◽  
Pyrite Oxidation ◽  
Outer Zone ◽  
Low Ph ◽  
Small Stream ◽  
Sand Aquifer ◽  
Uranium Tailings ◽  
Stream Bed

Abstract Investigations of the geochemistry of inactive pyritic uranium tailings in the Elliot Lake Mining district of Ontario have focused on the Nordic tailings management area, where two impoundments are located in natural bedrock basins. The tailings are 8-12 m thick and overlie a localized deposit of glaciofluvial sands. Analyses of the solid, liquid, and gas phases in the vadose zone of the tailings show that gas-phase oxygen levels drop rapidly within 0.7 to 1.5 m of the surface, indicating rapid oxygen consumption during pyrite oxidation. Oxidation during the past 15 to 20 years has caused a marked depletion of near-surface pyrite. The oxidation of pyrite in the vadose zone imparts to infiltrating precipitation high concentrations of Fe, SO42-, various heavy metals, and a pH generally between 1.5 and 4. The acidic infiltration moves downward at a rate of 0.2 to 2.0 m/yr, displacing high-pH groundwater that originated as process water discharged from the mill. It now occupies the entire tailings thickness over a small area of the tailings. At one location a well-defined plume of high-Fe2+ tailings-derived groundwater has developed in the sand aquifer adjacent to the tailings. The plume consists of three zones: an inner core characterized by Fe > 5000 mg/L, pH < 4.8, and elevated concentrations of several heavy metals and radionuclides; an outer zone with Fe < 2500 mg/L, pH > 5.5, and relatively low concentrations of heavy metals and radionuclides; and a transition zone separating the two. Although the average linear groundwater velocity is about 440 m/yr near the dam, reactions such as mineral dissolution, precipitation and coprecipitation retard the migration of the front of the inner core, producing an observed frontal migration rate of approximately 1 m/yr. Groundwater from the outer zone of the plume flows laterally towards a small stream, where a portion of it is now discharging into the stream bed. The discharge results in the precipitation of amorphous ferric hydroxide on the stream bed. Most of the H+ produced by Fe precipitation is buffered, and only a moderate decrease in stream pH is observed. Inner zone conditions will not reach the stream unless input of low-pH groundwater from the tailings continues for several hundred years. Although the rate of pyrite oxidation in the Nordic Main tailings has been decreasing, there is sufficient pyrite in the tailings to generate high-Fe groundwater for several decades or more. Calculated groundwater migration rates indicate that in the next few decades acidic, low-pH groundwater will occupy the entire tailings thickness over most of the tailings area, causing an increase in the total flux of contaminated groundwater into the underlying aquifer. The outer zone of the plume has already arrived at a small stream, and acidification of the surface waters may increase if the Fe concentration in the groundwater seepage increases.

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