J. Chen, J. Fooks and H. Goertz Water Survey Division Environment Canada 2008.05
description
Transcript of J. Chen, J. Fooks and H. Goertz Water Survey Division Environment Canada 2008.05
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44thth International Symposium on Flood Defence International Symposium on Flood Defence: : Managing Flood Risk, Reliability and Managing Flood Risk, Reliability and Vulnerability, Toronto, Ontario, Canada, May 6-8, 2008Vulnerability, Toronto, Ontario, Canada, May 6-8, 2008
J. Chen, J. Fooks and H. GoertzJ. Chen, J. Fooks and H. Goertz
Water Survey Division Water Survey Division Environment CanadaEnvironment Canada
2008.052008.05
Stage-Discharge Rating Stage-Discharge Rating with ADCP Measurementswith ADCP Measurements
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IntroductionIntroduction
Discharge measurement techniquesDischarge measurement techniques
ADCP data analysis ADCP data analysis
Stage-discharge ratingStage-discharge rating
ConclusionsConclusions
Presentation OutlinePresentation Outline
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Water Survey of CanadaWater Survey of Canada
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Discharge Measurement Discharge Measurement with Traditional Techniques with Traditional Techniques
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Limitations of Current Limitations of Current Meter MeasurementMeter Measurement
Discrete points and assumed vertical Discrete points and assumed vertical
velocity profilevelocity profile
Limited range of velocity (>6 cm/s)Limited range of velocity (>6 cm/s)
Time consumingTime consuming
Safety concernsSafety concerns
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Discharge Measurement Discharge Measurement with Acoustic Techniques with Acoustic Techniques
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Advantages of Acoustics Advantages of Acoustics TechniquesTechniques
Continuous velocity profiling with Continuous velocity profiling with directional capabilitydirectional capability Extended range of velocity measurementExtended range of velocity measurement Shortened field measurement timeShortened field measurement time Ability to correct data files in post-Ability to correct data files in post-processingprocessing Safety concerns decreasedSafety concerns decreased
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Discharge Measurement Discharge Measurement with ADCPwith ADCP
From USGS report
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Discharge Measurement Discharge Measurement with ADCP with ADCP (Cont’d)(Cont’d)
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Velocity Magnitude ContourVelocity Magnitude Contour
Discharge Measurement June 11, 2002
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Discharge Measurement Discharge Measurement with ADCP – 5 Components with ADCP – 5 Components
Top subsection
Bottom subsection
Channel subsection measurablewith an ADCP
Right banksubsection
Left banksubsection
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Percentage of ADCP Percentage of ADCP Measured Component QMeasured Component Q
0.08
21.1
65.66
10.31
2.85
0
10
20
30
40
50
60
70
Left Q Top Q Measured Q Bottom Q Right Q
(%)
Left Q
Top Q Measured Q
Bottom Q Right Q
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Correlation Among Correlation Among Component Discharges (Q-Q)Component Discharges (Q-Q)
Qtotal Qleft Qtop Qm Qbottom Qright
Qtotal -
Qleft 0.655 -
Qtop 0.936 0.851 -
Qm 0.997 0.626 0.914 -
Qbottom 0.981 0.753 0.981 0.964 -
Qright 0.503 0.310 0.473 0.471 0.538 -Pearson Correlation
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Correlation Analysis of Correlation Analysis of Component Discharge (H-Q)Component Discharge (H-Q)
0.622
0.479
0.9190.969 0.997 0.998
0
0.10.2
0.3
0.40.5
0.6
0.7
0.80.9
1
left Right Top Bottom Measured Total
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Discharge Computation Discharge Computation MethodsMethods
Standard stage-discharge ratingStandard stage-discharge rating Non-standard methods for discharge Non-standard methods for discharge
computationcomputation Index-velocity ratingIndex-velocity rating Flow-velocity distributionFlow-velocity distribution
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Stage vs. Measured Q RatingStage vs. Measured Q Rating
Qm = -0.5731H2 + 19.18H - 98.925
R2 = 0.996
0
9
18
27
36
5 6 7 8 9 10H (m)
Qm(m
3/s
)
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Stage vs. Estimated Top, Stage vs. Estimated Top, Bottom Components Q RatingBottom Components Q Rating
Qtop = 0.3512H2 - 3.8141H + 11.617
R2 = 0.9615
0
2
4
6
8
5 6 7 8 9 10H (m)
Qto
p(m
3 /s)
Qbottom = 0.1357H2 - 0.6302H - 1.1768
R2 = 0.9773
0
1
2
3
4
5
6
5 6 7 8 9 10H (m)
Qbo
ttom
(m3 /s
)
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Q = 0.1928H2 - 2.6567H + 9.2706
R2 = 0.9149
0
0.2
0.4
0.6
0.8
1
5 6 7 8 9 10H (m)
Qle
ft(m
3 /s)
Q = -0.2694H2 + 4.3744H - 16.973
R2 = 0.7534
0
0.2
0.4
0.6
0.8
1
5 6 7 8 9 10H (m)
Qrig
ht(m
3 /s)
Stage vs. Estimated Left, Stage vs. Estimated Left, Right Components Q RatingRight Components Q Rating
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Stage – Discharge RatingStage – Discharge RatingResults ComparisonResults Comparison
-30.00-20.00
-10.000.00
10.00
20.0030.00
40.0050.00
0.00 9.00 18.00 27.00 36.00 45.00Q (m3/s)
Erro
r %
Measured QUnmeasured QTop QBottom Q
2020
H&Q Rating with Single H&Q Rating with Single Transect MeasurementsTransect Measurements
Discharge measurement from each Discharge measurement from each transect is considered as an independent transect is considered as an independent measurement measurement
Significantly increase the number of Significantly increase the number of
measurements for rating curve measurements for rating curve
development development
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Q = -0.1647H2 + 16.482H - 96.292
R2 = 0.9994
0
9
18
27
36
45
5 6 7 8 9 10H (m)
Q(m
3 /s)
-10.00
-5.00
0.00
5.00
10.00
15.00
20.00
0.00 9.00 18.00 27.00 36.00 45.00
Q (m3/s)
Erro
r %
Verification Calibration
H&Q Rating with Single H&Q Rating with Single Transect MeasurementsTransect Measurements
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ADCP measurements with 5 components ADCP measurements with 5 components allow for exploration of disaggregated rating allow for exploration of disaggregated rating methodsmethods Component discharge ratingComponent discharge rating
It appears that H-Q rating quality does not vary It appears that H-Q rating quality does not vary significantly, regardless of whether discharge components significantly, regardless of whether discharge components are summed prior to rating calibration, or if individual are summed prior to rating calibration, or if individual component rating results are summedcomponent rating results are summed Component discharge percentages can provide future Component discharge percentages can provide future knowledge of error sources at particular sitesknowledge of error sources at particular sites
Conclusions Conclusions
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Single transect analysisSingle transect analysis Using an average of 4 transects or individual Using an average of 4 transects or individual transects does not significantly affect the H & Q transects does not significantly affect the H & Q rating accuracyrating accuracy Further study with rapidly changing stage Further study with rapidly changing stage could provide more depth to this analysiscould provide more depth to this analysis
Conclusions Conclusions (Cont’d)(Cont’d)
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Comments on Stage Comments on Stage Discharge RatingDischarge Rating
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4
4 5 6 7 8 9 10 11 12Q (m3/s)
H (
m) Series1
Series2
Series3
Series4
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Comments on Stage Comments on Stage Discharge Rating Discharge Rating (Cont’d)(Cont’d)
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16
17
18
19
20
21
22
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10/27/2004 19:12
10/28/2004 0:00
10/28/2004 4:48
10/28/2004 9:36
10/28/2004 14:24
10/28/2004 19:12
10/29/2004 0:00
10/29/2004 4:48
Date/Time
V (
cm/s
)
0.57
0.575
0.58
0.585
0.59
0.595
0.6
0.605
0.61
H (m
etr
es)
Velocity Water Level