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CYWD 2007QAQC Results
Sarah Hogg
Conservation Halton
Preliminary Data Analysis
• 431 sites observed total• 115 QAQC sites total• 26.6 % QAQC sites• Percent agreement on perched versus non-perched
culverts = 94.3% (agency staff issue)• Percent agreement wet
versus dry streams = 100%
Data Analysis Overview
• Identified 3 different crew types on CYWD: Volunteer Crew, Volunteer QAQC Crew, Agency Crew
• Hierarchy of methods used on day: Volume/Time, HH, Distance/Time
• Final Q value for each site determined based on discharge value observed by agency staff using best available method
• Analyzed data based on:1.) Comparison based on best measure of discharge2.) Variance between crews using the same method
Comparison Based on Best Measure of Discharge
• Relatively few observation points for each method• Standard deviation values high in comparison to discharge values observed • Negative slopes observed are attributed to methods where variance and
measurability decrease as velocity increases • One agency HH measurement omitted from analysis (obvious outlier)• Agency Vol/Time was value used for most Final Q values
Table 1: Comparison based on the best measure of discharge using the hierarchy of methods n R2 Slope Intercept Standard Deviation Conclusions/Comments
Agency Vol/Time 7 1.00 1.000 0.000 0.000 used for final Q valuesVolunteer Vol/Time 7 0.54 10.384 -0.010 0.140Volunteer QAQC Vol/Time 4 0.44 -0.342 0.002 0.026 negative slopeAgency HH 14 1.00 1.008 -0.001 0.050Volunteer HH 9 0.07 -0.010 0.001 0.038 negative slopeVolunteer QAQC HH 12 0.38 0.419 0.009 0.144Agency Dist/Time 7 0.83 2.662 -0.009 0.103 high correlationVolunteer Dist/Time 8 0.01 0.132 0.014 0.167Volunteer QAQC Dist/Time 6 0.22 0.204 0.011 0.104
Volume Time Q Value Comparison by Crew Type
00.005
0.010.015
0.020.025
0.030.035
0.04
0 0.002 0.004 0.006 0.008 0.01
Final Q Value (cms)
Cre
w Q
Val
ue (c
ms)
Volunteer
Volunteer QAQC
Agency
Distance Time Q Value Comparison by Crew Type
0
0.02
0.04
0.06
0.08
0.1
0 0.02 0.04 0.06 0.08 0.1
Final Q Value (cms)
Cre
w Q
Val
ue (c
ms)
Volunteer
Volunteer QAQC
Agency
Method Comparison by Crew Type
Hydraulic Head Q Value Comparison by Crew Type
0
0.05
0.1
0.15
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14
Final Q Value (cms)
Cre
w Q
Val
ue
(cm
s)
Volunteer
Volunteer QAQC
Agency
•Similar slope observed by all crews types for most methods
•Bias obvious for some methods (ie: HH)
•Slope of volunteer QAQC line is always closer to agency than individual volunteer
Comparison Between Crews Using Same Method
• Relatively few observation points • Standard deviation between crews relatively low• Negative slopes observed for methods where variance
increases with increased flow (Volume/Time and HH)
Table 2: Comparison between crews using similar methodsn R2 Slope Intercept SD Conclusions/Comments
Volunteer Vol/Time Versus Agency Vol/Time 6 0.05 0.108 0.001 0.027Volunteer HH Versus Agency HH 7 0.01 -0.005 0.000 0.027 negative slopeVolunteer Dist/Time Versus Agency Dist/Time 6 0.58 0.471 0.001 0.044Volunteer Vol/Time Versus Volunteer QAQC Vol/Time 4 0.57 0.619 0.000 0.025Volunteer HH Versus Volunteer QAQC HH 6 0.14 -0.030 0.001 0.042 negative slopeVolunteer Dist/Time Versus Volunteer QAQC Dist/Time 6 0.43 -0.001 0.625 0.095 negative slopeVolunteer QAQC Vol/Time Versus Agency Vol/Time 4 0.07 -0.173 0.002 0.033 negative slopeVolunteer QAQC HH Versus Agency HH 11 0.89 0.626 0.001 0.094 high correlationVolunteer QAQC Dist/Time Versus Volunteer Dist/Time 5 0.07 0.311 0.006 0.095
Comparison Between Crews Using Same Method
• Good agreement for the HH measures
• Some evidence that the QAQC crew was more similar to the agency crew than the average volunteer
Method Comparison: Volunteer Versus Volunteer QAQC
0
0.02
0.04
0.06
0 0.02 0.04 0.06
Q Value (cms) Observed by Volunteer QAQC
Q V
alu
e (c
ms
) O
bse
rved
b
y V
olu
nte
er Vol/Time versus Vol/Time
HH versus HH
Dist/Time versus Dist/Time
Method Comparison: Volunteer QAQC Versus Agency
0
0.05
0.1
0.15
0 0.05 0.1 0.15
Q Value (cms) Observed by Agency
Q V
alu
e (c
ms)
Ob
serv
ed
by
Vo
lun
teer
QA
QC
Vol/Time Versus Vol/Time
HH Versus HH
Dist/Time Versus Dist/Time
Method Comparison: Volunteer Versus Agency
0
0.01
0.02
0.03
0.04
0 0.01 0.02 0.03 0.04
Q Value (cms) Observed by Agency
Q V
alu
e (c
ms)
O
bse
rved
by
Vo
lun
teer
Vol/Time Versus Vol/Time
HH Versus HH
Dist/Time Versus Dist/Time
Conclusions/Recommendations
• Scale issue (confidence intervals for methods not known)
• Measures of HH seem to be done quite well, exception is when HH is low (>2)
• Distance/Time and Volume/Time methods not as repeatable
Conclusions/Recommendations (cont’d)
Recommendations:
• Low hydraulic head is low (>2mm) use distance/time, when and where appropriate
• More emphasis should be placed on accuracy of float and volume by time
• Go downstream to measure flow!
• Next Step – write up