Difference between revisions of "Instrument characteristics of point-integrating suspended load samplers"

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This article is a summary of section 5.2 of the [[Manual Sediment Transport Measurements in Rivers, Estuaries and Coastal Seas]] <ref>Rijn, L. C. van (1986). ''Manual sediment transport measurements''. Delft, The Netherlands: Delft Hydraulics Laboratory</ref>. This article provides insight in some characteristics of [[suspended load]] samplers, such as the sampling period, the minimum cycle period and the overall accuracy.
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==Introduction==
 
==Introduction==
 
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[[Image:H52figure1.jpg|thumb|right|Figure 1: Instrument characteristics]]
The most important characteristics of the point-integrating suspended load samplers are summarized. The results are presented in Figure 1 below. Hereafter, some of the characteristics are discussed.
+
The most important characteristics of the point-integrating [[suspended load]] samplers are summarized. The results are presented in Figure 1 below. Hereafter, some of the characteristics are discussed.
  
 
==Sampling period==
 
==Sampling period==
 
 
The sampling period is the time period during which a sample is collected. For the bottle-type and trap-type samplers the sampling period is equal to the filling period of the bottle or trap. The sampling period of the Delft Bottle is restricted by the size of the sediment catch which should be small compared with the size of the sedimentation chamber of the instrument. The sampling period of the pump-filter sampler is restricted by the filter characteristics. A small 50 um-filter may be blocked rather easily, especially in a silty environment. The sampling period of the optical and acoustical samplers is free. For time-averaging additional equipment should be used allowing a digital reading.
 
The sampling period is the time period during which a sample is collected. For the bottle-type and trap-type samplers the sampling period is equal to the filling period of the bottle or trap. The sampling period of the Delft Bottle is restricted by the size of the sediment catch which should be small compared with the size of the sedimentation chamber of the instrument. The sampling period of the pump-filter sampler is restricted by the filter characteristics. A small 50 um-filter may be blocked rather easily, especially in a silty environment. The sampling period of the optical and acoustical samplers is free. For time-averaging additional equipment should be used allowing a digital reading.
  
 
==Minimum cycle period==
 
==Minimum cycle period==
 
 
The minimum cycle period is the minimum time period between two successive measurements at adjacent points in a vertical. In case of a free sampling period a minimum sampling period of about 5 minutes is used to obtain the minimum cycle period, as given in Figure 1. The cycle period can be used to evaluate the time period needed to cover a full concentration profile measurement. In case of tidal flow conditions this latter period should be small in relation to the tidal period.
 
The minimum cycle period is the minimum time period between two successive measurements at adjacent points in a vertical. In case of a free sampling period a minimum sampling period of about 5 minutes is used to obtain the minimum cycle period, as given in Figure 1. The cycle period can be used to evaluate the time period needed to cover a full concentration profile measurement. In case of tidal flow conditions this latter period should be small in relation to the tidal period.
  
 
==Overall accuracy==
 
==Overall accuracy==
 
 
The overall accuracy is an estimate of the overall error of a single measurement due to (systematic and random) measuring errors and stochastic (fluctuation) errors related to the physical process. The latter errors are introduced by the stochastic fluctuations of the physical parameters to be measured. For example, single bottle-measurements may have an error of about 100%. This error can be reduced by using a larger sampling period or by collecting more samples. The overall accuracy of the samplers with a free sampling period, as presented in Figure 1, is based on a relatively long sampling period (say 5 minutes). The accuracy of the optical and acoustical samplers is largely dependent on the number and accuracy of the calibration samples.
 
The overall accuracy is an estimate of the overall error of a single measurement due to (systematic and random) measuring errors and stochastic (fluctuation) errors related to the physical process. The latter errors are introduced by the stochastic fluctuations of the physical parameters to be measured. For example, single bottle-measurements may have an error of about 100%. This error can be reduced by using a larger sampling period or by collecting more samples. The overall accuracy of the samplers with a free sampling period, as presented in Figure 1, is based on a relatively long sampling period (say 5 minutes). The accuracy of the optical and acoustical samplers is largely dependent on the number and accuracy of the calibration samples.
 
 
 
[[Image:H52figure1.jpg|thumb|left|'''Figure 1: ''Instrument characteristics''''']]
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
==References==
 
<references/>
 
 
  
 
==See also==
 
==See also==
 +
===Summaries of the manual===
 +
* [[Manual Sediment Transport Measurements in Rivers, Estuaries and Coastal Seas]]
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* Chapter 1: [[Introduction, problems and approaches in sediment transport measurements]]
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* Chapter 2:  [[Definitions, processes and models in morphology]]
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* Chapter 3: [[Principles, statistics and errors of measuring sediment transport]]
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* Chapter 4: [[Computation of sediment transport and presentation of results]]
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* Chapter 5: [[Measuring instruments for sediment transport]]
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* Chapter 6: [[Measuring instruments for particle size and fall velocity]]
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* Chapter 7: [[Measuring instruments for bed material sampling]]
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* Chapter 8: [[Laboratory and in situ analysis of samples]]
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* Chapter 9: [[In situ measurement of wet bulk density]]
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* Chapter 10: [[Instruments for bed level detection]]
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* Chapter 11: [[Argus video]]
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* Chapter 12: [[Measuring instruments for fluid velocity, pressure and wave height]]
  
===Other contributions of Leo van Rijn===
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===Other internal links===
 
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Examples of point-integrated suspended load samplers:
====articles with parts of the manual====
+
* [[Bottle samplers]]
*[[Manual Sediment Transport Measurements in Rivers, Estuaries and Coastal Seas]]
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* [[Trap samplers]]
 
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* [[USP-61 suspended load sampler]]
*[[INTRODUCTION, PROBLEMS AND APPROACHES IN SEDIMENT TRANSPORT MEASUREMENTS]]
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* [[Delft Bottle suspended load sampler]]
*[[DEFINITIONS, PROCESSES AND MODELS IN MORPHOLOGY]]
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* [[Pump-filter sampler]]
*[[PRINCIPLES, STATISTICS AND ERRORS OF MEASURING SEDIMENT TRANSPORT]]
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* [[Pump-sedimentation sampler]]
*[[COMPUTATION OF SEDIMENT TRANSPORT AND PRESENTATION OF RESULTS]]
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* [[Pump-bottle sampler]]
*[[MEASURING INSTRUMENTS FOR SEDIMENT TRANSPORT]]
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* [[Optical backscatter point sensor (OBS)]]
*[[MEASURING INSTRUMENTS FOR PARTICLE SIZE AND FALL VELOCITY]]
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* [[Optical Laser diffraction instruments (LISST)]]
*[[MEASURING INSTRUMENTS FOR BED MATERIAL SAMPLING]]
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* [[Acoustic point sensors (ASTM, UHCM, ADV)]]
*[[LABORATORY AND IN-SITU ANALYSIS OF SAMPLES]]
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* [[Acoustic backscatter profiling sensors (ABS)]]
*[[IN-SITU MEASUREMENT OF WET BULK DENSITY]]
 
*[[INSTRUMENTS FOR BED LEVEL DETECTION]]
 
*[[ARGUS VIDEO]]
 
*[[MEASURING  INSTRUMENTS FOR FLUID VELOCITY, PRESSURE AND WAVE HEIGHT]]
 
 
 
==== other articles ====
 
 
 
*[[Instrument Characteristics of Point-Integrating Suspended Load Samplers]]
 
*[[Guidelines instruments]]
 
*[[Instruments for rivers]]
 
*[[Instruments for estuaries]]
 
*[[Instruments for coasts]]
 
*[[bed load transport]]
 
 
 
==External links==
 
 
 
==Crediting the authors==
 
  
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===External links===
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* PDF of chapter 5 of the manual: [http://www.wldelft.nl/rnd/intro/fields/morphology/pdf/H5_Measuring_instruments_sediment_transport.pdf]
  
 
{{author  
 
{{author  
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|AuthorFullName= Roberti, Hans
 
|AuthorFullName= Roberti, Hans
 
|AuthorName=Robertihans}}
 
|AuthorName=Robertihans}}
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[[Category:Theme 9]]
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[[Category:Techniques and methods in coastal management]]
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[[Category:Manual sediment transport measurements]]

Revision as of 14:45, 26 November 2007

This article is a summary of section 5.2 of the Manual Sediment Transport Measurements in Rivers, Estuaries and Coastal Seas [1]. This article provides insight in some characteristics of suspended load samplers, such as the sampling period, the minimum cycle period and the overall accuracy.

Introduction

Figure 1: Instrument characteristics

The most important characteristics of the point-integrating suspended load samplers are summarized. The results are presented in Figure 1 below. Hereafter, some of the characteristics are discussed.

Sampling period

The sampling period is the time period during which a sample is collected. For the bottle-type and trap-type samplers the sampling period is equal to the filling period of the bottle or trap. The sampling period of the Delft Bottle is restricted by the size of the sediment catch which should be small compared with the size of the sedimentation chamber of the instrument. The sampling period of the pump-filter sampler is restricted by the filter characteristics. A small 50 um-filter may be blocked rather easily, especially in a silty environment. The sampling period of the optical and acoustical samplers is free. For time-averaging additional equipment should be used allowing a digital reading.

Minimum cycle period

The minimum cycle period is the minimum time period between two successive measurements at adjacent points in a vertical. In case of a free sampling period a minimum sampling period of about 5 minutes is used to obtain the minimum cycle period, as given in Figure 1. The cycle period can be used to evaluate the time period needed to cover a full concentration profile measurement. In case of tidal flow conditions this latter period should be small in relation to the tidal period.

Overall accuracy

The overall accuracy is an estimate of the overall error of a single measurement due to (systematic and random) measuring errors and stochastic (fluctuation) errors related to the physical process. The latter errors are introduced by the stochastic fluctuations of the physical parameters to be measured. For example, single bottle-measurements may have an error of about 100%. This error can be reduced by using a larger sampling period or by collecting more samples. The overall accuracy of the samplers with a free sampling period, as presented in Figure 1, is based on a relatively long sampling period (say 5 minutes). The accuracy of the optical and acoustical samplers is largely dependent on the number and accuracy of the calibration samples.

See also

Summaries of the manual

Other internal links

Examples of point-integrated suspended load samplers:

External links

  • PDF of chapter 5 of the manual: [1]
The main author of this article is Rijn, Leo van
Please note that others may also have edited the contents of this article.

Citation: Rijn, Leo van (2007): Instrument characteristics of point-integrating suspended load samplers. Available from http://www.coastalwiki.org/wiki/Instrument_characteristics_of_point-integrating_suspended_load_samplers [accessed on 19-09-2020]


The main author of this article is Roberti, Hans
Please note that others may also have edited the contents of this article.

Citation: Roberti, Hans (2007): Instrument characteristics of point-integrating suspended load samplers. Available from http://www.coastalwiki.org/wiki/Instrument_characteristics_of_point-integrating_suspended_load_samplers [accessed on 19-09-2020]

  1. Rijn, L. C. van (1986). Manual sediment transport measurements. Delft, The Netherlands: Delft Hydraulics Laboratory