Bedload monitoring system - Revision history

Bendikhansen at 11:57, 30 September 2020

2020-09-30T11:57:26Z

Bendikhansen at 11:57, 30 September 2020

2020-09-30T11:57:16Z

C.rachelly: /* Introduction */

2020-09-21T05:52:02Z

Introduction

C.rachelly: /* Other information */

2020-09-21T05:37:08Z

Other information

C.rachelly: /* Other information */

2020-09-21T05:36:24Z

Other information

C.rachelly: /* Application */

2020-09-21T05:33:00Z

Application

C.rachelly: /* Application */

2020-09-20T12:54:36Z

Application

C.rachelly: /* Introduction */

2020-09-20T12:49:17Z

Introduction

C.rachelly: /* Introduction */

2020-09-18T15:10:01Z

Introduction

C.rachelly: /* Relevant literature */

2020-09-18T15:03:07Z

Relevant literature

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 {{Note|This technology has been developed in the FIThydro project! See [[Innovative technologies from FIThydro]] for a complete list.|reminder}}
-'''Note: This article will be finished with the submission of deliverable 3.3 and 3.4 in October, 2020'''
 =Quick summary=
 [[file:bms_sensor.png|thumb|500px|Figure 1: (a) Geophone and accelerometer installed in a watertight housing mounted on an impact plate and exemplary (b) geophone and (c) accelerometer signal of the identical single grain impact. SumIMP denotes the total number of peaks above a threshold amplitude Amin. Amaxmax is the maximum amplitude registered during this event. Only positive amplitude values are considered (source: VAW).]]

@@ Line 1: / Line 1: @@
 {{Note|This technology has been developed in the FIThydro project! See [[Innovative technologies from FIThydro]] for a complete list.|reminder}}
+'''Note: This article will be finished with the submission of deliverable 3.3 and 3.4 in October, 2020'''
 =Quick summary=
 [[file:bms_sensor.png|thumb|500px|Figure 1: (a) Geophone and accelerometer installed in a watertight housing mounted on an impact plate and exemplary (b) geophone and (c) accelerometer signal of the identical single grain impact. SumIMP denotes the total number of peaks above a threshold amplitude Amin. Amaxmax is the maximum amplitude registered during this event. Only positive amplitude values are considered (source: VAW).]]

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 =Introduction=
-An indirect Bedload Monitoring System (BMS) was developed to monitor bedload transport through a vortex tube system installed in the headwater channel of the FIThydro case study hydropower plant (HPP) Schiffmühle (Rachelly et al. 2019). BMSs allow the quantitative assessment of bedload transport in rivers, torrents, and hydraulic sediment diversion structures. These measurements can support the evaluation of bedload continuity across hydropower plants or other hydraulic structures.
+Indirect bedload monitoring systems (BMS) allow the qualitative and quantitative assessment of bedload transport in watercourses (Gray et al. 2010). Applied at hydropower plants (HPP) or other hydraulic structures, these measurements can support the evaluation of bedload continuity across them. In the scope of FIThydro, a BMS was installed to monitor bedload transport in a vortex tube system at the case study HPP Schiffmühle (Rachelly et al. 2019).
-The BMS consists of two passive acoustic sensors, i.e. a geophone (GS-20DX manufactured by Geospace Technologies, Houston TX, USA) and an accelerometer (ICP352C03 manufactured by PCB Piezoelectronics, Depew NY, USA), mounted on an impact plate in a watertight housing (Figure 1a). The sensors do not directly measure bedload transport but register the impact plate's vibration, i.e. oscillations induced by the impingement of passing bedload particles. In the case study HPP Schiffmühle, the impact plate is the steel wall of the vortex tube (Figure 1a and 3a). The vibration signal output of both sensors is a voltage that is sampled at a frequency of 51.2 kHz. The raw signals are then transmitted and further processed (Figure 1b, c).
+The BMS installed at HPP Schiffmühle consists of two passive acoustic sensors, i.e. a geophone (GS-20DX manufactured by Geospace Technologies, Houston TX, USA) and an accelerometer (ICP352C03 manufactured by PCB Piezoelectronics, Depew NY, USA). The sensors do not directly measure bedload transport but register the impact plate's vibration, i.e. oscillations induced by the impingement of passing bedload particles. In the case study HPP Schiffmühle, the steel wall of the vortex tube is used as impact plate, and the sensors in a watertight housing are directly attached to it (Figure 1a and 3a). The vibration signal is sampled at a frequency of 51.2 kHz, transmitted, and then further processed (Figure 1b, c).
 The BMS presented here is similar to the Swiss Plate Geophone System (SPGS) (Rickenmann et al. 2012), but includes an additional accelerometer sensor to expand the range of frequencies and hence the potentially detectable particle sizes compared to the SPGS.
-The maximum amplitude recorded during a bedload transport event can be related to the maximum grain diameter. Additionally, the sum of impulse counts above a certain amplitude threshold can be connected to the transported bedload volume. Both relations are BMS setup- and site-dependent and calibration is therefore required to correlate the recorded impact signals to known bedload transport rates, often obtained from traditional bedload sampling (Rickenmann et al. 2012). If possible, calibration in a laboratory flume as well as in the field setting is recommended (Gray et al. 2010, Rickenmann et al. 2014, Wyss et al. 2016a, Wyss et al. 2016b, Albayrak et al. 2017).
+The maximum amplitude recorded during a bedload transport event can be related to the maximum grain diameter. Additionally, the sum of impulse counts above a certain amplitude threshold can be connected to the transported bedload volume. Both relations are BMS setup- and site-dependent, and calibration is therefore required to correlate the recorded impact signals to known bedload transport rates, often obtained from traditional bedload sampling (Rickenmann et al. 2012). If possible, calibration in a laboratory flume as well as in the field setting is recommended (Gray et al. 2010, Rickenmann et al. 2014, Wyss et al. 2016a, Wyss et al. 2016b, Albayrak et al. 2017).
 =Application=

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 =Other information=
-The total costs for the geophone and accelerometer sensors amount to approx. 900-1'400 €. The costs for the field computer, the analog-digital-converter, and the 3G modem are approx. 5'300-6'200 €. Depending on the site conditions and set-up, additional costs must be considered for the installation, data transmission, and calibration.
+The total costs for the geophone and accelerometer sensors amount to approx. 900-1'400 €. The costs for the field computer, the analog-digital-converter, and the 3G modem are approx. 5'300-6'200 €. Depending on the site conditions and setup, additional costs must be considered for the installation, data transmission, and calibration.
 =Relevant literature=

@@ Line 32: / Line 32: @@
 =Other information=
-The total costs for the geophone and accelerometer sensors amount to approx. 885-1'330 €. The costs for the field computer, the analog-digital-converter, and the 3G modem are approx. 5'300-6'200 €. Additional costs must be considered for the installation, data transmission and calibration, depending on the site conditions and set-up.
+The total costs for the geophone and accelerometer sensors amount to approx. 900-1'400 €. The costs for the field computer, the analog-digital-converter, and the 3G modem are approx. 5'300-6'200 €. Depending on the site conditions and set-up, additional costs must be considered for the installation, data transmission, and calibration.
 =Relevant literature=

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 Within the scope of FIThydro, a BMS consisting of a geophone and accelerometer was installed on the vortex tube at HPP Schiffmühle, which diverts bedload from the headwater channel to the residual flow reach (Rachelly et al. 2019). The vortex tube consists of a steel tube embedded in the side weir, connecting the two parallel channels (Figure 2). A gate valve positioned in the side weir opens automatically when a predefined discharge is exceeded. The opening of the valve automatically triggers the BMS measurements.
-In contrast to the SPGS, the steel tube is used as an impact plate for the BMS and the sensors are mounted directly onto the outside of the steel tube (Figure 3). Therefore, laboratory calibration was not easily possible. Instead, the system was calibrated in the field by repeatedly dumping sediment samples of known grain size distribution and volume upstream of the vortex tube and subsequently flushing them to the residual flow reach. In addition, drop tests with single grains were performed when the vortex tube was not in operation. The single grain signals help to understand the influence of grain size, grain form, drop height, and drop location on the amplitude and frequency of the signal.
+In contrast to the SPGS, the steel tube is used as an impact plate for the BMS, and the sensors are mounted directly onto the outside of the steel tube (Figure 3). Therefore, laboratory calibration was not easily possible. Instead, the system was calibrated in the field by repeatedly dumping sediment samples of known grain size distribution and volume upstream of the vortex tube and subsequently flushing them to the residual flow reach. In addition, drop tests with single grains were performed when the vortex tube was not in operation. The single grain signals help understand the influence of grain size, grain form, drop height, and drop location on the signal's amplitude and frequency.
-The first results of the presented BMS are promising, but the data analysis will be further refined and extended. Furthermore, a larger number of recorded flood events is necessary to check the plausibility of the results obtained so far. Overall, this study shows that the measurement principle of the SPGS can be extended to non-standardized impact plates such as steel vortex tubes, and to the use of an additional accelerometer sensor, given that appropriate calibration measures are taken.
+The first results of the presented BMS are promising, but the data analysis will be further refined and extended. Furthermore, a larger number of recorded flood events is necessary to check the plausibility of the results obtained so far. Overall, this study shows that the SPGS measurement principle can be extended to non-standardized impact plates such as steel vortex tubes and to the use of an additional accelerometer sensor, given that appropriate calibration measures are taken.
 =Relevant mitigation measures and test cases=

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 =Introduction=
-An indirect Bedload Monitoring System (BMS) is developed for bedload transport monitoring in the vortex tube system installed in the headwater channel of the FIThydro case study hydropower plant (HPP) Schiffmühle (Rachelly et al. 2019). The BMS allows the quantitative assessment of bedload transport in rivers, torrents and hydraulic sediment diversion structures. These measurements can support the evaluation of bedload continuity across hydropower plants or other hydraulic structures.
+An indirect Bedload Monitoring System (BMS) is developed for bedload transport monitoring in the vortex tube system installed in the headwater channel of the FIThydro case study hydropower plant (HPP) Schiffmühle (Rachelly et al. 2019). The BMS allows the quantitative assessment of bedload transport in rivers, torrents, and hydraulic sediment diversion structures. These measurements can support the evaluation of bedload continuity across hydropower plants or other hydraulic structures.
-The BMS consists of two passive acoustic sensors, i.e. a geophone (GS-20DX manufactured by Geospace Technologies, Houston TX, USA) and an accelerometer (ICP352C03 manufactured by PCB Piezoelectronics, Depew NY, USA), mounted on an impact plate in a watertight housing (Figure 1a). The sensors do not directly measure bedload transport, but register the vibration signals of the impact plate, i.e. oscillations induced by the impingement of passing bedload particles. In the case study HPP, the impact plate is the steel wall of the vortex tube (Figure 1a and 3a). The vibration signal output of both sensors is a voltage that is sampled at a frequency of 51.2 kHz. The raw signals are then transmitted and further processed (Figure 1b, c).
+The BMS consists of two passive acoustic sensors, i.e. a geophone (GS-20DX manufactured by Geospace Technologies, Houston TX, USA) and an accelerometer (ICP352C03 manufactured by PCB Piezoelectronics, Depew NY, USA), mounted on an impact plate in a watertight housing (Figure 1a). The sensors do not directly measure bedload transport but register the impact plate's vibration, i.e. oscillations induced by the impingement of passing bedload particles. In the case study HPP, the impact plate is the steel wall of the vortex tube (Figure 1a and 3a). The vibration signal output of both sensors is a voltage that is sampled at a frequency of 51.2 kHz. The raw signals are then transmitted and further processed (Figure 1b, c).
 The BMS presented here is similar to the Swiss Plate Geophone System (SPGS) (Rickenmann et al. 2012), but includes an additional accelerometer sensor to expand the range of frequencies and hence the potentially detectable particle sizes compared to the SPGS.
-The maximum amplitude recorded during a bedload transport event can be related to the maximum grain diameter. Additionally, the sum of impulse counts above a certain amplitude threshold can be related to the transported bedload volume. Both relations are BMS setup- and site-dependent, and a calibration is therefore required to correlate the recorded impact signals to known bedload transport rates, often obtained from traditional bedload sampling (Rickenmann et al. 2012). If possible, a calibration in a laboratory flume as well as in the field setting is recommended (Gray et al. 2010, Rickenmann et al. 2014, Wyss et al. 2016a, Wyss et al. 2016b, Albayrak et al. 2017).
+The maximum amplitude recorded during a bedload transport event can be related to the maximum grain diameter. Additionally, the sum of impulse counts above a certain amplitude threshold can be connected to the transported bedload volume. Both relations are BMS setup- and site-dependent and calibration is therefore required to correlate the recorded impact signals to known bedload transport rates, often obtained from traditional bedload sampling (Rickenmann et al. 2012). If possible, a calibration in a laboratory flume as well as in the field setting is recommended (Gray et al. 2010, Rickenmann et al. 2014, Wyss et al. 2016a, Wyss et al. 2016b, Albayrak et al. 2017).
 =Application=

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 *Gray, J.R., Laronne, J.B., Marr, J.D.G. (2010). Bedload-surrogate Monitoring Technologies, US Geological Survey Scientific Investigations Report 2010-5091. US Geological Survey: Reston VA. https://pubs.usgs.gov/sir/2010/5091/
-*Rachelly, C., Albayrak, I., Boes, R.M., Weitbrecht, V. (2019). Bed-Load Diversion with a Vortex Tube System. In E-proceedings of the 38th IAHR World Congress, Panama City, Panama, 5900-5909. https://doi.org/10.3850/38WC092019-0718
+*Rachelly, C., Albayrak, I., Boes, R.M., Weitbrecht, V. (2019). Bed-Load Diversion with a Vortex Tube System. In E-proceedings of the 38th IAHR World Congress, Panama City, Panama, 5900-5909. https://www.research-collection.ethz.ch/handle/20.500.11850/370865
 *Rickenmann, D., Turowski, J.M., Fritschi, B., Klaiber, A., Ludwig, A. (2012). Bedload transport measurements at the Erlenbach stream with geophones and automated basket samplers. Earth Surface Processes and Landforms, 37, 1000-1011. https://doi.org/10.1002/esp.3225