Revision History for Techniques and Methods 3-A22 Measuring Discharge with Acoustic Doppler Current Profilers from a Moving Boat Chapter 22 of Book 3, Section A By David S. Mueller and Chad R. Wagner ----------------------------------------------------- Posted online January 22, 2009 ----------------------------------------------------- Revised and reposted February 26, 2009 The text was modified as follows: Page 37 - In the sentence introducing equations A2-A4, "forward" was changed to "downstream." A change was made to equation A2. In the "where" explanation for Vy and Vx, "upstream" was changed to "downstream." Page 56 - The first matrix, for the SonTek/VSI RiverSurveyor, was changed. ----------------------------------------------------- Revised and reposted on March 5, 2014, as TM 3-A22, Version 2.0 -------------------------------------------------------------------- The list below contains information on the important updates and changes in this revision when compared to the original publication (2009). The list is not exhaustive, but is intended to highlight differences of interest to the majority of those that perform moving-boat ADCP discharge measurements. • Author information has been updated: By David S. Mueller, Chad R. Wagner, Michael S. Rehmel, Kevin A. Oberg, and Francois Rainville • Discussion of Instruments – Updated descriptions of instruments including signal processing, frequency, and transducers (p. 2). • Data Management – Added that all aspects of data management must follow agency policy and be documented in the offices surface-water quality-assurance plan. Encour-ages scanning of paper measurement notes to an electronic file (p. 3). • Training – Added that training must comply with agency required training standards and highly encourages additional training in order to stay current (p. 4). • Unmeasured Areas in a Profile –Added discussion of blanking distances for additional instruments (p. 6). • Configuration and Characteristics –Added characteristics for additional instruments (p. 7). • Testing Requirements and Procedures – Added section describing when an instrument must be tested and a matrix of quality-assurance test requirements (p. 10). • Transformation Matrix Check – Added description of methods for verifying that the correct transformation matrix is stored in the ADCP (p. 11). • Instrument History Log – Added a discussion on the importance of logging instrument quality-assurance tests (p. 12). • GPS Requirements and Specifications –Added specific precision requirements neededfor the GPS data output and a discussion of VTG limitations (p. 12). • Manned Boats – Added discussions of tethered boats used from a manned boat (p. 13). • Tethered Boats – Added discussions about why to avoid wading with a tethered boat across the stream, recommendations of unmanned cableways, safety considerations, and use of tethered boats in high velocity situations (p. 14). • Remote-Controlled Boats – Added concern of potential effect of motors and batteries on the compass (p. 18). • Other Equipment – Added electronic field notes (p. 18). • Variation in Speed of Sound with Depth – Added discussion that some software can correct the vertical velocity or depth for changes in the speed of sound and that phased array ADCPs horizontal velocities are unaffected by changes in speed of sound, but vertical velocity and depth are still dependent on correcting the speed of sound (p. 22). • Water Temperature – Clarified thatADCP temperature comparisons are for quality assurance only and should not be released to the public when not using a thermometer that meets USGS water temperature field measurement standards (p. 22). • Salinity – Set minimum bounds when salinity is expected to be sampled to 5 parts per thousand (p. 22). • Compass Calibration – Expanded descriptions of compass calibrations, highlighting potential issues (p. 23). • Instrument Configuration – Expanded discussion to include new instruments withauto-adaptive capabilities (p. 24). • Stationary Test with GPS and Loop Test – Added new table on moving-bed detection methods (p. 26–27). • Changing and Tidal Flow Situations – Added discussion of moving-bed test require-ments for multiple measurements in changing flow conditions (p. 27). • Selecting the Measurement Method Based on Moving-Bed Test Results – Added discussion to emphasize that bottom track is the preferred navigation method, and GPS is preferred in moving-bed conditions when available (p. 28). • Steady-Flow Conditions – Added new policy that measurement should have total exposure time greater than 720 seconds with at least 2 reciprocal transects (p. 28). • Unsteady-Flow Conditions – Updated for 720 second exposure time policy (p. 29). • Measuring in Difficult Conditions – Difficult conditions encountered in hydroacoustidischarge measurements are identified and the best procedures for collecting andprocessing data are discussed (p. 29). • Critical Data-Quality Problems – Updated with recommendation to view track reference code in RiverSurveyor Live while collecting data and to watch for erroneous compass headings when using GPS or Loop moving-bed method (p. 31). • Boat Operation – Updated to emphasize smooth, consistent boat motion (p. 31). • Estimating Edge Discharge – Added that individual edge discharge greater than 5 percent of total discharge must be measured or estimated with alternative method and other additional guidance on edge discharges (p. 32). • Field Notes – Updated to include electronic field notes (p. 33). • Post-Measurement Field Procedures – Added steps to obtain final dischage prior to leaving site (p. 34). • Data Storage and Database Entry – Added new good practice suggestions for storing field measurements with both electronic and paper notes (p. 37). • Measurement Checking and Review – Noted that office policy onADCP measurement checking and review should be documented in the local surface-water quality-assurance plan (p. 37). • Added Glossary (p. 41).