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Overview of ADCP “Best Practices” Report Measuring Discharge with Acoustic Doppler Current Profilers from a Moving Boat Techniques and Methods Report Chapter.

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Presentation on theme: "Overview of ADCP “Best Practices” Report Measuring Discharge with Acoustic Doppler Current Profilers from a Moving Boat Techniques and Methods Report Chapter."— Presentation transcript:

1 Overview of ADCP “Best Practices” Report Measuring Discharge with Acoustic Doppler Current Profilers from a Moving Boat Techniques and Methods Report Chapter 22 of Book3, Section A

2 Overview Why a Techniques and Methods Report Why a Techniques and Methods Report Organization of the report Organization of the report Highlight selected topics Highlight selected topics Changes to existing policy Changes to existing policy Quick-Reference guides and other forms Quick-Reference guides and other forms Availability of printed copies Availability of printed copies

3 Why and How COE funded development of two guidance reports for ADCP use COE funded development of two guidance reports for ADCP use Discharge Discharge Velocity Mapping Velocity Mapping Revised more general COE report to USGS specific T&M Revised more general COE report to USGS specific T&M USGS specific policy USGS specific policy StreamPro StreamPro Updated with latest guidance Updated with latest guidance

4 Source of Material Little “new” information Little “new” information Consolidated information from: Consolidated information from: QA/QC report QA/QC report OSW Technical Memos OSW Technical Memos ADCP Training Classes ADCP Training Classes Hydroacoustic Updates Hydroacoustic Updates Added some changes to guidance based on latest experience Added some changes to guidance based on latest experience Published to allow additional updates without republishing entire report Published to allow additional updates without republishing entire report

5 Organization Main Body contains guidance Main Body contains guidance Predeployment Preparation Predeployment Preparation Field Procedures Field Procedures Office Procedures Office Procedures Appendices contain details Appendices contain details Basic ADCP Operational Concepts Basic ADCP Operational Concepts Collecting Data in Moving-Bed Conditions Collecting Data in Moving-Bed Conditions Description of Water Modes Description of Water Modes Beam-Alignment Tests Beam-Alignment Tests Forms and Quick-Reference Guides Forms and Quick-Reference Guides Measurement Review Procedures Measurement Review Procedures

6 Predeployment Understand basic limitations of ADCP Understand basic limitations of ADCP Apply ADCP limitations to site selection and expected performance in the field Apply ADCP limitations to site selection and expected performance in the field Sediment Sediment Unmeasured areas Unmeasured areas Configuration Configuration Compass Compass A) Excessive Backscatter B) Excessive Attenuation

7 Predeployment – cont. Instrument Quality Assurance Instrument Quality Assurance Beam Alignment Test Beam Alignment Test Recommended Recommended 1 st acquired 1 st acquired After factory repair After factory repair After firmware or hardware upgrades After firmware or hardware upgrades Periodically Periodically Detailed procedures in Appendix D Detailed procedures in Appendix D Typically for Rio Grandes and RiverSurveyors Typically for Rio Grandes and RiverSurveyors Periodic Instrument Comparison Periodic Instrument Comparison

8 Predeployment – cont. Ancillary Equipment Ancillary Equipment GPS GPS VTG and GGA VTG and GGA Echo Sounder Echo Sounder Deployments and Mounts Deployments and Mounts Other Equipment Other Equipment Final Equip Preparation and Inspection Final Equip Preparation and Inspection Verify all computer connections and communications before going to the field!! Verify all computer connections and communications before going to the field!!

9 Checklist in Appendix E

10 Field Procedures Site Selection Site Selection Maybe the most important thing you do in the field. Maybe the most important thing you do in the field. Location, shape, velocity, other Location, shape, velocity, other Pre-Measurement Field Procedures Pre-Measurement Field Procedures Set clock Set clock Diagnostic tests Diagnostic tests Speed of sound (temp and salinity) Speed of sound (temp and salinity) Compass calibration Compass calibration Instrument configuration Instrument configuration Use wizards Use wizards Moving-bed tests Moving-bed tests

11 Policy Change USGS policy (U.S. Geological Survey, 2002b; Oberg and others, 2005) requires that a moving-bed test be conducted prior to making a discharge measurement. In USGS training classes and in Oberg and others (2005), an exception to conducting a moving- bed test with every measurement was allowed if sufficient documentation was provided in the field folder to justify not conducting a moving-bed test. Field experience has shown that sediment transport characteristics can vary greatly for the same discharge, depending on the hydrograph shape, source of runoff, and season of the year. Thus, a moving bed may be detected at a location and discharge where one was not previously detected, or a moving bed may no longer exist at a location and discharge where one was previously detected. Moving-bed conditions also have been observed in low-velocity environments (less than 1 ft/s) and are likely caused by organic material transported by the water. Therefore, to ensure the quality of the data collected, every moving-boat measurement made with an ADCP must have a recorded moving-bed test. If a site routinely has a moving bed and GPS is always used with the ADCP, a moving-bed test is still required but need only be 5 minutes in length. This requirement supersedes Oberg and others (2005) and various USGS training materials.

12 Moving-Bed Test Requirements Loop test preferred Loop test preferred Stationary tests Stationary tests When When If compass calibration is not good If compass calibration is not good If bottom tracking cannot be maintained If bottom tracking cannot be maintained StreamPro StreamPro How How 5-minutes in duration 5-minutes in duration With GPS With GPS From a tagline or bridge or anchored From a tagline or bridge or anchored 10-minutes in duration 10-minutes in duration No GPS from manned or RC-boat No GPS from manned or RC-boat These criteria supersede the guidance on stationary moving-bed tests that have been published previously in U.S. Geological Survey (2002b) and Oberg and others (2005).

13 Field Procedures – cont. Discharge Measurement Procedures Discharge Measurement Procedures No changes to existing guidance No changes to existing guidance Step by step quick-reference guides in Appendix E Step by step quick-reference guides in Appendix E Post-Measurement Field Procedures Post-Measurement Field Procedures An 8-pass measurement due to one or more transects being >5% from mean does not constitute a check measurement An 8-pass measurement due to one or more transects being >5% from mean does not constitute a check measurement Check measurements are required according to criteria in WSP 2175 Check measurements are required according to criteria in WSP 2175

14 Office Procedures Preventive Maintenance Preventive Maintenance Saves time in the long term!!! Saves time in the long term!!! Data Storage Data Storage Follow office policy Follow office policy Put data on server (usually within 72 hours) Put data on server (usually within 72 hours) Measurement Review Measurement Review Data-Quality Indicators Data-Quality Indicators Commonly Observed Problems Commonly Observed Problems

15 Measurement Review 1.Field forms complete, understandable, and legible. 2.Electronic files backup in field and archived in office. 3.Number of transects appropriate and in reciprocal pairs. 4.Configuration a)Correct and appropriate b)User input agrees with field form c)Edge, top, and bottom extrapolations appropriate

16 Measurement Review – cont. 5.Independent temperature measurement recorded and checked. 6.Salinity measured and recorded. 7.Moving-bed test recorded and appropriate procedures used. 8.Slow smooth boat operation. 9.Edge distance measured, recorded, and consistent with electronic data. 10.Number and location of missing or invalid ensembles are acceptable.

17 Measurement Review – cont. 11.Number and location of invalid depth cells are acceptable. 12.Top and bottom extrapolation methods have been reviewed and are appropriate. 13.Measurement computations, including mean discharge and measurement gage height, are correct.

18 Missing and Invalid Data WinRiver II RiverSurveyor

19 Ambiguity Errors

20 Signal Attenuation

21 Beam Impinging on Wall

22 Smooth Boat Operation WinRiver II RiverSurveyor

23 Spikes in Streambed

24 Bad GPS

25 Appendix A – Basic Concepts Doppler Concepts Doppler Concepts Narrowband and Broadband Narrowband and Broadband Computing Velocity in Orthogonal Coordinates Computing Velocity in Orthogonal Coordinates Measuring a Velocity Profile Measuring a Velocity Profile Computing Discharge Computing Discharge

26 Appendix B- Collecting Data in Moving-Bed Conditions Cause and Effect of Moving-Bed Cause and Effect of Moving-Bed Methods to Indentify a Moving Bed Methods to Indentify a Moving Bed More detail than in main body of report More detail than in main body of report Stationary, no GPS Stationary, no GPS Stationary, with GPS Stationary, with GPS Loop Loop Methods to Account for Moving-Bed Effects Methods to Account for Moving-Bed Effects GPS GPS Loop method Loop method Multiple moving-bed test method Multiple moving-bed test method Mid-section method Mid-section method Azimuth method Azimuth method

27 Appendix C – Description of Water Modes SonTek/YSI RiverSurveyor SonTek/YSI RiverSurveyor TRDI TRDI Rio Grande Rio Grande 1 5/11 5/ StreamPro StreamPro , C, Low-Noise 13, C, Low-Noise

28 Appendix D – Beam-Alignment Test Detailed instructions and criteria for conducting a beam alignment test Detailed instructions and criteria for conducting a beam alignment test Typically only applied to: Typically only applied to: Rio Grande Rio Grande RiverSurveyor RiverSurveyor

29 Appendix E – Forms and Quick-Reference Guides

30 Rio Grande Quick Sheet

31 RiverSurveyor Quick Sheet

32 Appendix F – Measurement Review Guides

33 Availability PDF version available now PDF version available now Linked from Linked from Printed version Printed version 3-hole punch, loose leaf 3-hole punch, loose leaf In printing now, available in a couple of months In printing now, available in a couple of months Announcement memo will be accompany printed version. Announcement memo will be accompany printed version.

34 Questions


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