1. 1 4 th International Symposium on Flood Defence: Managing Flood Risk, Reliability and Vulnerability, Toronto, Ontario, Canada, May 6-8, 2008 J. Chen, J. Fooks and H. Goertz Water Survey Division Environment Canada 2008.05 Stage-Discharge Rating with ADCP Measurements

2. 2  Introduction  Discharge measurement techniques  ADCP data analysis  Stage-discharge rating  Conclusions Presentation Outline

3. 3 Water Survey of Canada

4. 4 Discharge Measurement with Traditional Techniques

5. 5 Limitations of Current Meter Measurement  Discrete points and assumed vertical velocity profile  Limited range of velocity (>6 cm/s)  Time consuming  Safety concerns

6. 6 Discharge Measurement with Acoustic Techniques

7. 7 Advantages of Acoustics Techniques  Continuous velocity profiling with directional capability  Extended range of velocity measurement  Shortened field measurement time  Ability to correct data files in post- processing  Safety concerns decreased

8. 8 Discharge Measurement with ADCP From USGS report

9. 9 Discharge Measurement with ADCP (Cont’d)

10. 10 Velocity Magnitude Contour Discharge Measurement June 11, 2002

11. 11 Discharge Measurement with ADCP – 5 Components Top subsection Bottom subsection Channel subsection measurable with an ADCP Right bank subsection Left bank subsection

12. 12 Percentage of ADCP Measured Component Q

13. 13 Correlation Among Component Discharges (Q-Q) Q total Q left Q top QmQm Q bottom Q right Q total - Q left 0.655- Q top 0.9360.851- QmQm 0.9970.6260.914- Q bottom 0.9810.7530.9810.964- Q right 0.5030.3100.4730.4710.538- Pearson Correlation

14. 14 Correlation Analysis of Component Discharge (H-Q)

15. 15 Discharge Computation Methods  Standard stage-discharge rating  Non-standard methods for discharge computation  Index-velocity rating  Flow-velocity distribution

16. 16 Stage vs. Measured Q Rating

17. 17 Stage vs. Estimated Top, Bottom Components Q Rating

18. 18 Stage vs. Estimated Left, Right Components Q Rating

19. 19 Stage – Discharge Rating Results Comparison

20. 20 H&Q Rating with Single Transect Measurements  Discharge measurement from each transect is considered as an independent measurement  Significantly increase the number of measurements for rating curve development

21. 21 H&Q Rating with Single Transect Measurements

22. 22  ADCP measurements with 5 components allow for exploration of disaggregated rating methods  Component discharge rating  It appears that H-Q rating quality does not vary significantly, regardless of whether discharge components are summed prior to rating calibration, or if individual component rating results are summed  Component discharge percentages can provide future knowledge of error sources at particular sites Conclusions

23. 23  Single transect analysis  Using an average of 4 transects or individual transects does not significantly affect the H & Q rating accuracy  Further study with rapidly changing stage could provide more depth to this analysis Conclusions (Cont’d)

24. 24 Comments on Stage Discharge Rating

25. 25 Comments on Stage Discharge Rating (Cont’d)