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