High-frequency absorbance measurements for sediment source apportionment – laboratory and field assessment

2021 ◽  
Author(s):  
Niels Lake ◽  
Núria Martínez-Carreras ◽  
Peter Shaw ◽  
Adrian Collins
Keyword(s):  
Particle Size ◽  
Source Apportionment ◽  
High Frequency ◽  
Soil Samples ◽  
Sediment Source ◽  
Water Tank ◽  
Sediment Sources ◽  
Environmental Objectives ◽  
Set Up ◽  
Artificial Mixtures

<p>To manage effectively excessive sediment inputs to rivers and streams, it is crucial to have detailed and reliable information on key sediment sources. Such evidence is important for implementing targeted measures for improving ecosystem functioning and meeting environmental objectives. Although sediment fingerprinting is increasingly adopted worldwide to provide such evidence, current procedures do not provide detailed information on how sediment sources can change over both short (e.g., events and in between events) and long (e.g., over seasons or years) time scales. These limitations are mainly due to the conventional methods used for target sediment sampling and the high workloads and costs associated with laboratory analyses for tracers, which limit both high-frequency and longer duration sampling campaigns. To address this issue, we propose the use of a submersible spectrophotometer, which measures absorbance in the UV-VIS range in situ and at high frequency (e.g., minutes) to trace suspended sediment sources. In our proof of concept investigation, the approach was first tested in a laboratory setting, using soil samples and artificial mixtures with known proportions of two, three and four soil source samples in an experimental water tank. A total of six soil samples were collected, which were sieved to different fractions to investigate the influence of particle size on the sensor absorbance readings. Both soil samples and artificial mixtures were suspended in the laboratory tank set-up at different concentrations to investigate the effects on: (i) absorbance, and; (ii) un-mixing accuracy. The results showed that absorbance was linearly additive and could be used to predict dominant samples in the artificial mixtures correctly using a Bayesian tracer un-mixing model, largely regardless of particle size and of the concentration inside the experimental tank. This approach is currently being tested in a field experiment in the Attert River Basin (Luxembourg) to investigate if the results found in the laboratory experiments hold under natural field conditions. Our preliminary insights into the use of absorbance for sediment source apportionment in the field will be presented.</p>

Improving spatial representation of erosion sources using Sediment Fingerprinting with terrain data and sediment budget modelling

2020 ◽  
Author(s):  
Simon Vale ◽  
Hugh Smith
Keyword(s):  
Suspended Sediment ◽  
Source Apportionment ◽  
End Users ◽  
Sediment Budget ◽  
Storm Event ◽  
Sediment Source ◽  
Sediment Fingerprinting ◽  
Sediment Sources ◽  
Geochemical Tracers ◽  
Source Contributions

<p>Sediment fingerprinting quantifies proportional contributions of catchment sediment sources to downstream sediment mixtures and deposits. While the sediment fingerprinting technique is well established it is still challenged by the coarse spatial resolution of sediment source discrimination which hinders understanding of catchment sediment dynamics and limits its usefulness for land management where finer resolution spatial information is required.</p><p>Here, two conventional sediment fingerprinting datasets from New Zealand are used to show how spatial modelling of source loads can improve 1) the usefulness of sediment fingerprinting approaches and 2) visualization of results for end-users by combining source apportionment with terrain information and sediment budget modelling. The two case studies involve unmixing sediment source contributions to 1) overbank deposits within the Oroua River catchment, where six sediment sources (Mountain Range, Mudstone, Hill Subsurface, Hill Surface, Unconsolidated Sandstone, and Channel Bank) across two size fractions (<63 µm and 125–300 µm) were characterized using bulk geochemical and radionuclide tracers and 2) suspended sediment in the Manawatu catchment, where a similar six sources were characterized using bulk geochemical tracers to determine changes in source contributions to hourly suspended sediment samples during a 53hr storm event.</p><p>The proportional source contributions for each case study are applied to modelled sediment loads and spatially distributed using terrain information for rock type, slope and channel network extent to produce specific sediment yield maps for both catchments and spatial visualization of sediment generation during the Manawatu catchment storm event. Integrating sediment fingerprinting results with spatial datasets and modelling can enhance interpretation of source apportionment results and improve the utility of this information for end-users focused on the spatial targeting of erosion sources for mitigation to reduce downstream sediment impacts.   </p>

Multi-fractional sediment fingerprinting in monitoring sediment sources in a peri-urban Portuguese catchment

2021 ◽  
Author(s):  
Rory Walsh ◽  
Carla Ferreira ◽  
William Blake ◽  
Sam Higton ◽  
Antonio Ferreira
Keyword(s):  
Particle Size ◽  
Suspended Sediment ◽  
Agricultural Land ◽  
Size Fraction ◽  
Soil Samples ◽  
Sediment Fingerprinting ◽  
Bed Sediment ◽  
Sediment Sources ◽  
Geochemical Composition ◽  
Size Fractions

<p>This paper explores the potential for using multiple particle size fractions in a hierarchical geochemical sediment fingerprinting approach to the assessment of changes in sediment sources through time within a small Mediterranean peri-urban catchment. Conventional  sediment fingerprinting has focussed on the <63µm fraction of fine bed-sediment on the basis that this fraction represents suspended sediment, which in turn is considered dominant over bedload in catchment sediment budgets. In reality, however, coarser sediment than 63µm may form part of suspended sediment and/or occurs as relatively fast-moving fine bedload.  Furthermore, sediment sources vary in their particle size distribution and, as geochemical composition can vary with particle size, it is arguable that sediment fingerprinting studies should consider use of multiple size fractions.</p><p>This study explores this approach using <63µm, 63-125µm, 125-250 µm and 250-2000µm size fractions.  It focuses on the north-south flowing Ribeira dos Covões catchment (6.2 km<sup>2</sup>), on the outskirts of Coimbra in central Portugal. The climate is humid Mediterranean. Catchment geology is 56% sandstone (in the east), 41 % marly limestone (in the west) and 3 % alluvium. Current land-use is 56% woodland, 4 % agricultural and 40% urban (mainly residential, but also including a recently constructed enterprise park (5%) and major highway (1%)). Recent urbanization has largely occupied former agricultural land. </p><p>The study adopts a multi-proxy sediment fingerprinting approach to assessment of changes in sediment sources, based on geochemical (elemental) characterization of the four different size fractions of fluvial bed-sediment and soil samples, using a Niton x-ray fluorescence (XRF) elemental analyser. Sampling of fluvial sediment was carried out at 33 sites within the stream network (including all significant tributaries, downstream sites and the catchment outlet). Samples were collected in July 2018 and November 2018 following contrasting ‘late-wet-season’ and ‘end-of-dry-season’ events. In July 2018, samples of potential sediment sources were collected including: (i) soil surface (0-2cm) samples at 64 locations, (ii) 17 samples from eroding channel margin sites, and (iii) 15 samples of road sediment. All fluvial and soil samples were sieved to obtain the four target size fractions. The elemental geochemistry of each sample fraction at all fluvial and source sites was derived using the XRF analyser.  (These results were added to similar datasets previously obtained on three occasions in 2012-15 in a period of enhanced urban constructional disturbance). Differences (and similarities) in geochemical signatures between the different size fractions at each survey date at and between each tributary and potential source site were assessed using a range of statistical techniques.  Messages arising are discussed. For each size fraction and survey date, Bayesian unmixing models were used in a hierarchical (confluence-based) fashion to assess the contributions of sub-catchments to downstream sites and the catchment outlet. Modelling results for the two 2018 events were validated by comparing them with suspended sediment records collected at five tributary locations and at the catchment outlet.  Although overall, the modelling was successful in indicating and quantifying significant changes in sediment sources through time within the catchment, uncertainties in interpretation of the multiple fractions are identified and discussed. </p>

scholarly journals High frequency un-mixing of soil samples using a submerged spectrophotometer in a laboratory setting—implications for sediment fingerprinting

2021 ◽  
Author(s):  
Niels F. Lake ◽  
Núria Martínez-Carreras ◽  
Peter J. Shaw ◽  
Adrian L. Collins
Keyword(s):  
Particle Size ◽  
Soil Sample ◽  
Suspended Sediment ◽  
Temporal Frequency ◽  
Soil Samples ◽  
Sediment Sources ◽  
High Temporal Frequency ◽  
Novel Method ◽  
The Relationship

Abstract Purpose This study tests the feasibility of using a submersible spectrophotometer as a novel method to trace and apportion suspended sediment sources in situ and at high temporal frequency. Methods Laboratory experiments were designed to identify how absorbance at different wavelengths can be used to un-mix artificial mixtures of soil samples (i.e. sediment sources). The experiment consists of a tank containing 40 L of water, to which the soil samples and soil mixtures of known proportions were added in suspension. Absorbance measurements made using the submersible spectrophotometer were used to elucidate: (i) the effects of concentrations on absorbance, (ii) the relationship between absorbance and particle size and (iii) the linear additivity of absorbance as a prerequisite for un-mixing. Results The observed relationships between soil sample concentrations and absorbance in the ultraviolet visible (UV–VIS) wavelength range (200–730 nm) indicated that differences in absorbance patterns are caused by soil-specific properties and particle size. Absorbance was found to be linearly additive and could be used to predict the known soil sample proportions in mixtures using the MixSIAR Bayesian tracer mixing model. Model results indicate that dominant contributions to mixtures containing two and three soil samples could be predicted well, whilst accuracy for four-soil sample mixtures was lower (with respective mean absolute errors of 15.4%, 12.9% and 17.0%). Conclusion The results demonstrate the potential for using in situ submersible spectrophotometer sensors to trace suspended sediment sources at high temporal frequency.

Soil response to chemicals used in a field experiment

2013 ◽  
Vol 27 (2) ◽  
pp. 151-158 ◽  
Author(s):  
S. Jezierska-Tys ◽  
A. Rutkowska
Keyword(s):  
Alkaline Phosphatase ◽  
Enzymatic Activity ◽  
Field Experiment ◽  
Soil Microorganisms ◽  
Block Design ◽  
Soil Samples ◽  
Alkaline Phosphatases ◽  
Soil Response ◽  
Negative Effect ◽  
Set Up

Abstract The effect of chemicals (Reglone 200 SL and Elastiq 550 EC) on soil microorganisms and their enzymatic activity was estimated. The study was conducted in a field experiment which was set up in the split-block design and comprised three treatments. Soil samples were taken six times, twice in each year of study. The results showed that the application of chemicals generally had no negative effect on the number of soil microorganisms. The application of Reglone 200 SL caused an increase of proteolytic and ureolytic activity and affected the activity of dehydrogenases, acid and alkaline phosphatases in the soil. The soil subjected of Elastiq 550 EC was characterized by lower activity of dehydrogenases, protease, urease and alkaline phosphatase.

scholarly journals Couplinator: A simple computational tool for synthesis of multi-section coupled-line filter based on MPCM-TLM technique

2021 ◽  
pp. 1-10
Author(s):  
E. Faghand ◽  
S. Karimian ◽  
E. Mehrshahi ◽  
N. Karimian
Keyword(s):  
Comparative Analysis ◽  
Transmission Line ◽  
High Frequency ◽  
Computational Tool ◽  
Cad Tools ◽  
Coupled Line ◽  
High Frequency Structure Simulator ◽  
Transmission Line Method ◽  
Set Up ◽  
Planar Circuit

Abstract A new simple computational tool is proposed for the synthesis of multi-section coupled-line filters based on combined modified planar circuit method (MPCM) and transmission line method (TLM) analysis, referred to as MPCM-TLM. Due to its fundamentally simple architecture, the presented tool offers significantly faster optimization of coupled-line filters – for exactly the same initial simulation set-up – than other costly commercially-available tools, giving equally reliable results. Validity and accuracy of the proposed tool have been verified through the design of 3rd, 5th, and 7th order coupled-line filters and comparative analysis between results obtained from the proposed approach and the high-frequency structure simulator. A remarkable 99% time reduction in the analysis is recorded in the case of 7th order filter using the proposed tool, for almost identical results to HFSS. Therefore, it can be confidently claimed that the proposed technique can be used as a reliable alternative to existing complex, costly, processor-intensive CAD tools.

Sediment source apportionment following wildfire in an upland commercial forest catchment

2021 ◽  
Author(s):  
Enrique Muñoz-Arcos ◽  
Alejandra Castillo ◽  
Alicia Cuevas-Aedo ◽  
Luis Ovando-Fuentealba ◽  
Alex Taylor ◽  
...  
Keyword(s):  
Source Apportionment ◽  
Sediment Source ◽  
Forest Catchment ◽  
Commercial Forest

scholarly journals USE OF SCALED SEMIVARIOGRAMS IN THE PLANNING SAMPLE OF SOIL CHEMICAL PROPERTIES IN SOUTHERN AMAZONAS, BRAZIL

2015 ◽  
Vol 39 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Ivanildo Amorim de Oliveira ◽  
Milton César Costa Campos ◽  
José Marques Junior ◽  
Renato Eleotério de Aquino ◽  
Daniel de Bortoli Teixeira ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Spherical Model ◽  
Exponential Model ◽  
Soil Samples ◽  
Soil Chemical Properties ◽  
Sampling Density ◽  
Sugarcane Crop ◽  
Lack Of Information ◽  
Set Up ◽  
Almost All

The lack of information concerning the variability of soil properties has been a major concern of researchers in the Amazon region. Thus, the aim of this study was to evaluate the spatial variability of soil chemical properties and determine minimal sampling density to characterize the variability of these properties in five environments located in the south of the State of Amazonas, Brazil. The five environments were archaeological dark earth (ADE), forest, pasture land, agroforestry operation, and sugarcane crop. Regular 70 × 70 m mesh grids were set up in these areas, with 64 sample points spaced at 10 m distance. Soil samples were collected at the 0.0-0.1 m depth. The chemical properties of pH in water, OM, P, K, Ca, Mg, H+Al, SB, CEC, and V were determined at these points. Data were analyzed by descriptive and geostatistical analyses. A large part of the data analyzed showed spatial dependence. Chemical properties were best fitted to the spherical model in almost all the environments evaluated, except for the sugarcane field with a better fit to the exponential model. ADE and sugarcane areas had greater heterogeneity of soil chemical properties, showing a greater range and higher sampling density; however, forest and agroforestry areas had less variability of chemical properties.

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.

scholarly journals Particle Size Estimation in Mixed Commercial Waste Images Using Deep Learning

2021 ◽  
Author(s):  
Phongsathorn Kittiworapanya ◽  
Kitsuchart Pasupa ◽  
Peter Auer
Keyword(s):  
Computer Vision ◽  
Particle Size ◽  
Deep Learning ◽  
Waste Management ◽  
State Of The Art ◽  
Learning Algorithms ◽  
Input Image ◽  
Size Estimation ◽  
Waste Particles ◽  
Set Up

<div>We assessed several state-of-the-art deep learning algorithms and computer vision techniques for estimating the particle size of mixed commercial waste from images. In waste management, the first step is often coarse shredding, using the particle size to set up the shredder machine. The difficulty is separating the waste particles in an image, which can not be performed well. This work focused on estimating size by using the texture from the input image, captured at a fixed height from the camera lens to the ground. We found that EfficientNet achieved the best performance of 0.72 on F1-Score and 75.89% on accuracy.<br></div>

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