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CYWD 2007

CYWD 2007. QAQC 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%.

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CYWD 2007

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  1. CYWD 2007 QAQC Results Sarah Hogg Conservation Halton

  2. 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%

  3. 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 discharge 2.) Variance between crews using the same method

  4. 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

  5. Method Comparison by Crew Type • 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

  6. 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)

  7. 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

  8. 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

  9. 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

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