International Measurement Campaign in Maastricht, the Netherlands, November 20Th 2012

department Mobility and Public Works

International measurement campaign in Maastricht, The Netherlands, November 20th 2012

Comparing ADP flow measurement by Flanders Hydraulics (HIC), Rijkswaterstaat (RWS) and Direction générale opérationnelle de la Mobilité et des Voies hydrauliques (SETHY)

12_149 WL Adviezen

Vlaamse overheid

International measurement campaign in Maastricht, The Netherlands, November 20th 2012

Comparing ADP flow measurement by Flanders Hydraulics (HIC), Rijkswaterstaat (RWS) and Direction générale opérationnelle de la Mobilité et des Voies hydrauliques (SETHY)

Cornet, E.; Vereecken, H.; Boeckx, L.; Mostaert, F.

April 2013

WL2013A12_149_rev2_0

F-WL-PP10-1 Versie 04 GELDIG VANAF: 12/11/2012 This publication must be cited as follows:

Cornet, E.; Vereecken, H.; Boeckx, L.; Mostaert, F. (2013). International measurement campaign in Maastricht, The Netherlands, November 20th 2012: Comparing ADP flow measurement by Flanders Hydraulics (HIC), Rijkswaterstaat (RWS) and Direction générale opérationnelle de la Mobilité et des Voies hydrauliques (SETHY). Version 2_0. WL Adviezen, 12_149. Flanders Hydraulics Research: Antwerp, Belgium.

Waterbouwkundig Laboratorium Flanders Hydraulics Research

B-2140 Antwerp Tel. +32 (0)3 224 60 35 Fax +32 (0)3 224 60 36 E-mail: [email protected] www.watlab.be

Nothing from this publication may be duplicated and/or published by means of print, photocopy, microfilm or otherwise, without the written consent of the publisher.

F-WL-PP10-1 Versie 04 GELDIG VANAF: 12/11/2012 Document identification

Title: International measurement campaign in Maastricht, The Netherlands, November 20th 2012: Comparing ADP flow measurement by Flanders Hydraulics (HIC), Rijkswaterstaat (RWS) and Direction générale opérationnelle de la Mobilité et des Voies hydrauliques (SETHY)

Customer: Waterbouwkundig Laboratorium Ref.: WL2013A12_149_rev2_0

Keywords (3-5): ADCP, debieten, AGILA

Text (p.): 17 Appendices (p.): /

Vertrouwelijk: ☐ Yes Exceptions: ☐ Customer ☐ Internal

☐ Flemish government

Released as from: ☒ No ☒ Available online

Approval

Author Reviser Project Leader Steunpunt HIC Division Head Cornet, E. Vereecken, H. Vereecken, H. Boeckx, L. Mostaert, F.

Revisions

Nr. Datum Omschrijving Auteur(s)

1_0 18/02/13 Conceptversie Emmanuel Cornet

1_1 25/02/13 Inhoudelijke revisie Hans Vereecken

1_2 02/04/13 Revisie opdrachtgever Jan Tekstra

2_0 10/04/13 Definitieve versie Emmanuel Cornet

Abstract

On November 20th 2012, at the initiative of Dutch Rijkswaterstaat (RWS), an international measurement campaign on the river Meuse at Maastricht (NL) took place with hydrometrists from the Flemish HIC, Dutch RWS and Walloon SETHY. The aim was to compare by means of simultaneous ADP-measurements the results produced by the calibration instruments of all three institutes and to favor best-practices and knowledge exchange.

Each group brought into action a trimaran mounted RDI-Rio Grande ADP instrument, while RWS additionnally put in the “Observant”, a small manned and ADP equipped measuring vessel. While the trimarans were consecutively towed between the Meuse banks from the “Hoge Brug” with 4 tracks per participating group, the Observant was sailing, slightly upstream (100m) and simultaneously without interruption, some 40 bank-to- bank tracks.

This report compares all measured discharge data to the simultaneous discharge data produced by the upstream acoustic flowmeter at MSW St.Pieters (ADM) with a 15 minute time shift taken into account. Tables are displaying the results of all sailed tracks, while AGILA-graphs present the averaged cross section shapes and the stream velocity distributon measured by all ADP-devices. Finally, a comparison is made of the Observant vs. the trimaran results and, on the other hand, of the Observant discharge data and the ADM ones.

F-WL-PP10-1 Versie 04 GELDIG VANAF: 12/11/2012 International measurement campaign in Maastricht, The Netherlands, November 20th 2012: Comparing ADP flow measurement by Flanders Hydraulics (HIC), Rijkswaterstaat (RWS) and Direction générale opérationnelle de la Mobilité et des Voies hydrauliques (SETHY)

Contents

1. Introduction ...... 1 2. Methodology ...... 2 2.1. Situation of measurements ...... 2 2.2. Measurement methodology ...... 3 2.3. Instrument configuration and Winriver configuration ...... 4 3. Results...... 5 3.1. WinRiver ...... 5 3.2. AGILA analysis ...... 5 3.3. Comparing measured discharge data with ADM output ...... 12 3.4. Comparing measured discharge data : trimaran vs. Observant ...... 16 4. Conclusion ...... 17

Final version WL2013A12_149_rev2_0 I F-WL-PP10-1 Version 04 RELEASED AS FROM: 12/11/2012

International measurement campaign in Maastricht, The Netherlands, November 20th 2012: Comparing ADP flow measurement by Flanders Hydraulics (HIC), Rijkswaterstaat (RWS) and Direction générale opérationnelle de la Mobilité et des Voies hydrauliques (SETHY)

List of tables

Table 1 - measurement configuration per instrument ...... 4 Table 2 - Overall discharge results ...... 6 Table 3 - discharge measurements per trimaran (QWinRiver) ...... 7 Table 4 - Discharge measurement Observant ...... 8 Table 5 - Overall results based on flow direction (first row) and direction of reference cross-section (= 83° Hoge Brug – second row) ...... 9 Table 6 - discharge data at MSW St.Pieter ADM ...... 12 Table 7 - Correcting ADM discharge values ...... 13 Table 8 – calibration time corrected ADM discharge values ...... 13 Table 9 - comparing trimaran vs. Observant avaraged discharge data ...... 16

Final version WL2013A12_149_rev2_0 II F-WL-PP10-1 Version 04 RELEASED AS FROM: 12/11/2012

List of figures

Figure 1 - Locations of the ADP-measurements and St.Pieter acoustic flowmeter ...... 2 Figure 2 - ADP-measurement zone detail ...... 3 Figure 3 - Averaged velocity distribution in AGILA of 4 ADP-tracks by HIC ...... 9 Figure 4 - Averaged velocity distribution in AGILA of 4 ADP-tracks by SETHY ...... 10 Figure 5 - Averaged velocity distribution in AGILA of 4 ADP-tracks by RWS ...... 10 Figure 6 - Averaged velocity distribution in AGILA of 39 ADP-tracks by Observant ...... 11 Figure 7 - Superposed cross-sections of all instruments ...... 11 Figure 8 - Time related discharge data from St.Pieter flowmeter and ADP-measurements ...... 15 Figure 9 - Calibration discharge results vs. corrected ADM St.Pieters discharge ...... 15

Final version WL2013A12_149_rev2_0 III F-WL-PP10-1 Version 04 RELEASED AS FROM: 12/11/2012

1. Introduction

On November 20th 2012, at the initiative of Dutch Rijkswaterstaat, an international measurement campaign on the river Meuse at Maastricht (NL) took place uniting Flanders Hydraulics-Hydrological Information Centre (HIC), the Dutch “Rijkswaterstaat-Directie Limburg” (RWS) and the Walloon “Direction générale opérationnelle de la Mobilité et des Voies hydrauliques” (SETHY). The aim was to compare by means of simultaneous ADP-measurements the results produced by the calibration instruments of all three institutes, to control the functioning, handling and quality and to exchange knowledge. Comparison of discharge results on all instruments could thus bring to light instrument disfunctions or poor configuration practice and avoid costly recalibration by the manufacturer.

Each group operated a trimaran mounted RDI-Rio Grande ADP instrument, while Rijkswaterstaat additionnally put in the “Observant”, a small manned and ADP equipped measuring vessel. While the trimarans were consecutively towed between the Meuse banks from the “Hoge Brug” with 4 tracks (or transects) per participating group, the Observant was sailing, slightly upstream (100m) and simultaneously without interruption, some 40 bank-to-bank tracks.

After the measurements, the results and AGILA-graphs were discussed at the Rijkswaterstaat-Direction Limburg.

We would like to thank all participants to this measurement campaign and are grateful to Ms. Lianita Costongs for contributing to the results analysis.

Final version WL2013A12_149_rev2_0 1 F-WL-PP10-1 Version 04 RELEASED AS FROM: 12/11/2012

2. Methodology

2.1. Situation of measurements

Fig. 1 shows the Maastricht area with the ADP-measurements site at some 2 km downstream of the acoustic flow monitoring station at St.Pieter. Fig. 2 zooms in on the measurements area downtown Maastricht, where the trimarans were being towed on the ‘Hoge Brug’, i.e. a pedestrian bridge and the ‘Observant’ measuring vessel was been sailing some 100m upstream.

Figure 1 - Locations of the ADP-measurements and St.Pieter acoustic flowmeter

Final version WL2013A12_149_rev2_0 2 F-WL-PP10-1 Version 04 RELEASED AS FROM: 12/11/2012

Figure 2 - ADP-measurement zone detail

2.2. Measurement methodology

The ADP-trimarans of all three institutes were slowly towed from one shore to the other, whereas data were instantaneously monitored on laptop. End of track by reaching the other riverbank was communicated by phone. The slinging velocities of the trimarans were subject to human variability while the operators focused on keeping sailing velocities constant and synchronously low. The Observant sailed 40 tracks, the first track being a round loop to the starting point, All tracks were performed with little or no harmful influence on measurement quality caused by river navigation. After the measurements, the results and AGILA-graphs were discussed at the Rijkswaterstaat-Direction Limburg office. AGILA’s main feature is to allow for projections on a reference cross section of the sailed ADP- measurements. Up until recent versions of AGILA, the cross section would be perpendicular to the resulting current direction. But AGILA allows now to custom the angle of the projection cross section. The AGILA results for both projection methods will be shown further on. The number of consecutive tracks per trimaran was 4, whereas the Observant made 40 tracks over the timespan of the trimarans operation. Clocks were exactly set equal in local time on all instruments. The first Observant-track being a loop cruise (in order to detect possible moving bed occurrence, thus Qtotal tending to zero i.e. Qtotal = -0.262 m³/s, table 3), the next 39 Observant-tracks were sailed along a straight line perpendicular on the bank across the river. The instruments were operated without GPS, since thus proved absence of moving bottom, the riverbed scanning by the ADP-bottom track function did not have to result in systematic discharge underestimation.

Final version WL2013A12_149_rev2_0 3 F-WL-PP10-1 Version 04 RELEASED AS FROM: 12/11/2012

2.3. Instrument configuration and Winriver configuration

Table 1 shows the field deployment and main configuration data on the trimaran ADP and on Observant. Table 2 and 3 show the WinRiver-results per instrument for all tracks. The total discharge depends on the computed partial discharges as the Doppler acoustic-measured Q, and the non measured bottom Q, top Q, left and right Q. The latter two depend on the left and right shore distances which were not equally configured per instrument, see instrument configuration table 1. Moreover, HIC chose for a different approach to determine near-shore discharge (Q left and right) by selecting with a coefficiënt 0.7 triangle for a different shape for the left and right bank type. Table 1 also shows the blanking distance to be equally set to 0.25m, which account for a homogeneous calculus of the non measured top and bottom discharges. Finally, the Observant-results are not perfectly comparable to the trimaran ones since the configured minimum cellsize could not be set less than 0.50m and the offset of the ADP-transducer not to the trimaran value of 8 cm.

Table 1 - measurement configuration per instrument

Observant RWS HIC SETHY

Instrument Rio Grande 600 Rio Grande 1200 Rio Grande 1200 Rio Grande 1200 kHz kHz kHz kHz

Cellsize (m) 0.50 0.25 0.25 0.25

Cells number 19 39 39 40

Blanking dist. (m) 0.25 0.25 0.25 0.25

Offset ADP 0.32 0.08 0.08 0.07 transducer (m)

Shore distance (m)

Right bank (begin) 6 8 5 (first 2) 8 (last 2) 8.80

Left bank (end) 6 5 5 (first 2) 8 (last 2) 5

Discharge

Power curve coeff Power 0.1167 Power 0.1167 Power 0.1167 Power 0.1167 (top + bott)

Left+Right bank Triangle 0.3535 Triangle 0.3535 Coeff. 0.7 Triangle 0.3535 edge type

Final version WL2013A12_149_rev2_0 4 F-WL-PP10-1 Version 04 RELEASED AS FROM: 12/11/2012

3. Results

3.1. WinRiver

All instruments rough data are processed by WinRiver II and chronologically listed in table 2 and 3 from the discharge summary (F12 button). WinRiver II allows for each track to be reproduced into an ASCII-output file required for further analysis in AGILA (Config, ASCII output > Classic ASCII output OFF, Playback > Reprocess Checked Transects).

3.2. AGILA analysis

All obtained ASCII-files are then per instrument read by AGILA (version 6.5.0.2). This software from the German Hydrological Institute (Bundesanstalt für Gewässerkunde) allows to process ADP-data independently from the measuring trajectory. The non linearly ADP-sailed tracks, spatial related data as wet section and velocity distribution, are, by means of projection, made comparable to the parameters obtained with classical current meters, which mostly are used from linear shaped objects such as bridges.

Per instrument, tracks can be superposed and averaged with respect to the projected wet profile and velocity distribution determined by the sailed ensembles and the configured cell size. These superposed profiles are shown by figures 3 to 6, whereas figure 7 shows the superposed profiles for all instruments linked to the 15 minute time shifted stage measured at the St.Pieter ADM flowmeter. This all-instruments superposition in AGILA is senseless with respect to the velocity distribution since tracks were not sailed simultaneously thus with different discharge and stage conditions.

According to figure 7, the Meuse bottom profile at ‘Hoge Brug’ seems to be well measured for all trimarans. As could be expected, the Observant profiles are obviously different from the trimaran ones because of the measurement site situated some 200m upstream from ‘Hoge Brug’. As a discharge result is not affected by the trajectory of the ADP-track, wet area surface and velocity data however are, and AGILA recalculates them to values that could be obtained if the track were sailed linearly. Normally, AGILA calculates a cross-section direction perpendicular to the resulting flow direction from all subvelocities and their compass-measured directions along the sailed track. But AGILA allows the user to input a constant cross-section direction for all tracks. This direction has been set to 83° for the ‘Hoge Brug’ (see fig 2), making the tracks results of all instruments, including Observant, better comparable. This comparison is shown in table 4 where all tracks per instrument are averaged and represented without and with the 83° projection. It is obvious that in these measurements the 83° projection has no significant effect on all discharge results. AGILA also provides for two discharge values, namely ‘Q-Trans’ and ‘Q-Agila’. Q-Trans should be equal to the WinRiver value as computed between two consecutive ensembles, whereas Q-Agila would be similar to a classical (propeller) measurement processing. Table 2 shows all discharge data per track. It will be clear that all discharge values : WinRiver, Q-Trans, Q- Agila and - the latter two also computed with the 83° projection -, do not significantly differ. It will be noted in figures 3 to 6 that with respect to the trimarans, the discharge area measured by Observant is smaller. This already was obvious in tables 3 en 4 which represent the ADP-measured discharges with respect to the top-, bottom-, left- and right discharge values and where the Qmeas/Qtotal ratio is 61% for the Observant, whereas 76-78% for the trimarans.

Final version WL2013A12_149_rev2_0 5 F-WL-PP10-1 Version 04 RELEASED AS FROM: 12/11/2012

All results are further on in this report compared to the simultaneous discharge output from the St.Pieter acoustic flowmeter station. Since this station is, by 2 km, significantly situated upstream the ‘Hoge Brug’, Rijkswaterstaat suggested a 15 minute time shift for comparison between the calibration result and the 10 minute time series from the flowmeter. These 10 minute values were averaged and recomputed 15 minutes back in time to make them comparable to the calibrating instruments.

Table 2 - Overall discharge results

automatic 83°-projection begintime QWinRiver Q-Trans Q-Agila Q-Trans Q-Agila Observant 11:09:28 164.90 164.88 166.06 164.77 166.29 Observant 11:13:00 155.76 155.26 155.61 155.19 155.75 Observant 11:15:08 176.55 176.59 175.97 176.64 175.60 Observant 11:17:25 169.06 169.30 168.63 169.19 168.29 Observant 11:19:48 173.88 174.57 173.90 174.41 173.49 Observant 11:22:15 184.35 183.89 183.32 183.83 182.86 Observant 11:24:57 180.38 180.02 179.82 179.99 179.74 Observant 11:30:20 193.63 193.37 191.97 193.05 192.04 HIC 11:31:31 202.69 187.51 187.60 187.46 186.86 Observant 11:34:36 180.80 180.25 179.74 180.21 179.53 Observant 11:37:41 166.62 166.52 165.97 166.60 165.82 HIC 11:38:58 169.49 168.78 169.62 168.77 169.08 Observant 11:41:21 165.87 164.82 164.19 164.71 164.15 Observant 11:45:32 158.31 158.56 158.30 158.51 157.89 Observant 11:48:35 178.72 177.95 178.00 177.96 178.06 Observant 11:52:03 175.22 174.97 173.80 174.87 174.19 HIC 11:52:04 178.25 176.95 177.05 176.68 176.04 Observant 11:55:42 176.26 173.99 173.82 174.04 173.91 HIC 11:57:44 162.39 161.41 162.03 161.37 161.96 Observant 11:58:54 156.39 150.15 149.01 150.07 149.57 Observant 12:02:20 166.87 163.84 162.97 163.88 162.56 Observant 12:05:37 171.01 170.80 171.40 170.75 171.72 Observant 12:09:10 173.71 173.37 173.26 173.29 173.36 Observant 12:11:58 169.33 169.03 166.93 168.78 166.33 SETHY 12:13:50 170.22 169.88 170.27 169.89 169.64 Observant 12:15:08 190.99 190.52 188.29 190.54 188.16 Observant 12:18:31 186.68 186.46 185.02 186.29 185.18 Observant 12:21:48 169.18 168.96 167.44 168.91 167.39 SETHY 12:22:52 191.33 191.34 191.60 191.27 191.17 Observant 12:25:04 164.06 164.12 163.82 164.02 164.54 Observant 12:28:33 172.18 171.87 171.27 171.79 171.14 SETHY 12:30:37 164.27 163.73 164.40 163.71 163.95 Observant 12:31:47 169.96 169.72 169.14 169.71 168.89 Observant 12:34:55 190.30 189.86 189.74 189.83 188.74 SETHY 12:38:22 173.75 173.52 173.16 173.45 172.91 Observant 12:39:03 153.26 152.97 150.12 152.65 149.34

Final version WL2013A12_149_rev2_0 6 F-WL-PP10-1 Version 04 RELEASED AS FROM: 12/11/2012

Observant 12:41:57 138.86 138.40 138.22 138.35 138.29 Observant 12:45:08 160.92 160.85 161.47 160.72 161.44 RWS 12:45:22 170.71 170.62 170.39 170.60 169.97 Observant 12:48:22 186.97 187.00 186.85 186.99 186.81 Observant 12:51:50 170.45 169.96 170.32 169.85 170.01 RWS 12:51:56 162.47 162.40 162.09 162.46 161.92 Observant 12:55:10 136.80 136.57 136.45 136.62 136.61 Observant 12:58:37 150.73 151.31 151.20 151.39 151.06 RWS 12:59:05 155.52 155.42 155.21 155.40 154.86 Observant 13:02:06 161.24 160.79 160.04 160.69 160.01 RWS 13:05:12 175.56 175.55 174.74 175.57 174.04 Observant 13:05:29 177.21 177.08 175.23 176.97 174.98 Observant 13:09:03 186.32 186.16 183.62 186.06 183.86 Observant 13:12:44 155.21 155.34 155.24 155.19 154.64 Observant 13:16:21 127.98 128.55 126.91 128.64 127.15

Table 3 - discharge measurements per trimaran (QWinRiver)

Final version WL2013A12_149_rev2_0 7 F-WL-PP10-1 Version 04 RELEASED AS FROM: 12/11/2012

Table 4 - Discharge measurement Observant

Final version WL2013A12_149_rev2_0 8 F-WL-PP10-1 Version 04 RELEASED AS FROM: 12/11/2012

Table 5 - Overall results based on flow direction (first row) and direction of reference cross-section (= 83° Hoge Brug – second row)

Figure 3 - Averaged velocity distribution in AGILA of 4 ADP-tracks by HIC

Final version WL2013A12_149_rev2_0 9 F-WL-PP10-1 Version 04 RELEASED AS FROM: 12/11/2012

Figure 4 - Averaged velocity distribution in AGILA of 4 ADP-tracks by SETHY

Figure 5 - Averaged velocity distribution in AGILA of 4 ADP-tracks by RWS

Final version WL2013A12_149_rev2_0 10 F-WL-PP10-1 Version 04 RELEASED AS FROM: 12/11/2012

Figure 6 - Averaged velocity distribution in AGILA of 39 ADP-tracks by Observant

Figure 7 - Superposed cross-sections of all instruments

Final version WL2013A12_149_rev2_0 11 F-WL-PP10-1 Version 04 RELEASED AS FROM: 12/11/2012

3.3. Comparing measured discharge data with ADM output

Table 6 shows the 10 minute discharge output at the St.Pieter flowmeter, 2 km upstream the calibration measurement site. In order to properly compare these two outputs, the flowmeter output series needed to be adapted 1. by a time shift due to the upstream situation of the flowmeter. This time shift was set at 15 minutes according to the Rijkswaterstaat St.Pieter flowmeter calibration practice. 2. by remodelling it into a 1 minute series instead of the 10 minute series which was considered too rough for comparison with the measurements time. Table 7 shows this remodelling creating a corrected discharge by averaging of the interpolated flowmeter value and the corresponding value from a 5th degree polynom Excel-computed trendline on the 10 minute flowmeter output. The result of this twofold manipulation is shown in table 8, were each instrument track is linked to a corrected flowmeter discharge value.

Table 6 - discharge data at MSW St.Pieter ADM

Final version WL2013A12_149_rev2_0 12 F-WL-PP10-1 Version 04 RELEASED AS FROM: 12/11/2012

Figure 8 shows the time-discharge data graph with all measured discharge values with respect to the rough measured and the time corrected ADM-St.Pieter flowmeter discharge results, wheras figure 9 displays the same calibration data (X) to the corrected ADM-discharges (Y).

Table 7 - Correcting ADM discharge values

Table 8 – calibration time corrected ADM discharge values

begintime endtime Q meas Q corr Observant 11:09:28 11:11:57 164.9 148.68 Observant 11:13:00 11:14:47 155.764 153.00 Observant 11:15:08 11:17:01 176.554 155.50 Observant 11:17:25 11:19:26 169.063 160.00 Observant 11:19:48 11:21:50 173.88 163.40 Observant 11:22:15 11:24:32 184.35 166.00 Observant 11:24:57 11:29:48 180.378 170.50 Observant 11:30:20 11:34:16 193.63 176.54 HIC 11:31:31 11:38:37 202.693 178.00 Observant 11:34:36 11:37:14 180.795 178.80 Observant 11:37:41 11:40:39 166.624 177.80 HIC 11:38:58 11:45:46 169.493 176.50 Observant 11:41:21 11:44:18 165.871 176.40 Observant 11:45:32 11:48:02 158.312 174.10 Observant 11:48:35 11:51:34 178.723 171.80 Observant 11:52:03 11:55:00 175.222 168.70 HIC 11:52:04 11:57:35 178.254 168.80 Observant 11:55:42 11:58:32 176.263 169.20

Final version WL2013A12_149_rev2_0 13 F-WL-PP10-1 Version 04 RELEASED AS FROM: 12/11/2012

HIC 11:57:44 12:03:41 162.387 171.20 Observant 11:58:54 12:01:50 156.385 171.20 Observant 12:02:20 12:05:13 166.873 172.90 Observant 12:05:37 12:08:32 171.007 171.30 Observant 12:09:10 12:11:16 173.708 168.70 Observant 12:11:58 12:14:44 169.329 165.50 SETHY 12:13:50 12:19:25 170.219 167.10 Observant 12:15:08 12:18:08 190.986 166.60 Observant 12:18:31 12:21:26 186.683 170.00 Observant 12:21:48 12:24:42 169.183 173.00 SETHY 12:22:52 12:30:10 191.329 173.10 Observant 12:25:04 12:27:59 164.056 173.30 Observant 12:28:33 12:31:21 172.183 171.30 SETHY 12:30:37 12:38:07 164.265 170.00 Observant 12:31:47 12:34:18 169.955 169.60 Observant 12:34:55 12:38:45 190.303 170.70 SETHY 12:38:22 12:43:18 173.745 173.50 Observant 12:39:03 12:41:24 153.263 173.50 Observant 12:41:57 12:44:46 138.864 175.80 Observant 12:45:08 12:48:03 160.919 174.00 RWS 12:45:22 12:51:13 170.713 172.00 Observant 12:48:22 12:51:16 186.974 170.00 Observant 12:51:50 12:54:48 170.446 164.50 RWS 12:51:56 12:58:02 162.469 164.00 Observant 12:55:10 12:58:06 136.796 163.60 Observant 12:58:37 13:01:27 150.725 164.40 RWS 12:59:05 13:04:22 155.523 164.70 Observant 13:02:06 13:05:02 161.238 165.00 RWS 13:05:12 13:11:09 175.556 163.20 Observant 13:05:29 13:08:26 177.213 163.80 Observant 13:09:03 13:12:15 186.315 161.80 Observant 13:12:44 13:15:51 155.213 159.20 Observant 13:16:21 13:18:59 127.979 157.20

Final version WL2013A12_149_rev2_0 14 F-WL-PP10-1 Version 04 RELEASED AS FROM: 12/11/2012

Figure 8 - Time related discharge data from St.Pieter flowmeter and ADP-measurements (graph by L. Costongs, RWS-directie Limburg)

Figure 9 - Calibration discharge results vs. corrected ADM St.Pieters discharge

Final version WL2013A12_149_rev2_0 15 F-WL-PP10-1 Version 04 RELEASED AS FROM: 12/11/2012

3.4. Comparing measured discharge data : trimaran vs. Observant

Table 9 shows the measured discharge by Observant corresponding to the time period the trimarans have been measuring. Absolute deviation values are not exceeding 4% which does not allow to conclude one of the trimaran calibration instruments to measure with poor accuracy.

Table 9 - comparing trimaran vs. Observant avaraged discharge data

Final version WL2013A12_149_rev2_0 16 F-WL-PP10-1 Version 04 RELEASED AS FROM: 12/11/2012

4. Conclusion

The prerequisite to all calibration measurement, namely an accurate measured wet profile over all tracks per instrument, was met. The trimarans profiles, regardless of chosen distances to the shores, are also very much resembling to each other and so are the Observant upstream measured profiles over 39 measured tracks. As for the velocity measurement, a very normal distribution of Doppler measured velocities resulted from all tracks. This can be seen in the AGILA output graphs. Discharge data per track over all instruments also seem to be regular and the WinRiver estimation in the ADP unmeasured zones (edge and blanking) does not result in significant deviations. The Observant ADP-measured area seems to be, as could be expected, smaller than the trimaran ones with Qmeas/Qtotal ratio = 61% for the Observant, whereas this ratio increases to 76-78% for the trimarans. Comparing simultaneously operating calibration instruments with each other did not reveal one or other instrument to measure with significant systematic errors. It also was worthwhile to compare the calibration results to the simultaneous flowmeter output (fig. 9). This comparison resulted in some scattering due to : • the distance (2 km) between the ADM flow meter location and the measurements in spite of the applied 15 min time shift • the questionable 1 minute ADM flow meter estimation based on the 10 minute output • turbulence caused by river navigation affecting the measurements It is therefore necessary that calibrations at least be performed at the ADM flow meter location in order to calibrate it properly. A flowmeter output with a small time step, e.g. a 1 minute step or even smaller, would be highly recommendable to achieve more accurate matching with calibration measurements. And calibration accuracy would be well served by navigation free conditions.

Final version WL2013A12_149_rev2_0 17 F-WL-PP10-1 Version 04 RELEASED AS FROM: 12/11/2012

Waterbouwkundig Laboratorium Flanders Hydraulics Research

B-2140 Antwerp Tel. +32 (0)3 224 60 35 Fax +32 (0)3 224 60 36 E-mail: [email protected] www.watlab.be