Computing Discharge Using the Index Velocity Method Techniques and Methods 3–A23
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Computing Discharge Using the Index Velocity Method Techniques and Methods 3–A23 U.S. Department of the Interior U.S. Geological Survey COVER DESIGN Photographs: Michael Hall, USGS South Carolina Water Science Center BROAD RIVER NEAR SOUTH CAROLINA Computing Discharge Using the Index Velocity Method By Victor A. Levesque and Kevin A. Oberg Techniques and Methods 3–A23 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior KEN SALAZAR, Secretary U.S. Geological Survey Marcia K. McNutt, Director U.S. Geological Survey, Reston, Virginia: 2012 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1–888–ASK–USGS. For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod To order this and other USGS information products, visit http://store.usgs.gov Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. Suggested citation: Levesque, V.A., and Oberg, K.A., 2012, Computing discharge using the index velocity method: U.S. Geological Survey Techniques and Methods 3–A23, 148 p. (Available online at http://pubs.usgs.gov/tm/3a23/) ISBN 978 1 4113 3285 0 iii Acknowledgments This report is a cooperative effort with contributions from many people. It reflects more than 20 years of experience and practice by personnel in the USGS. Many instructors and students have provided inspiration and information for this report. In particular, the authors acknowledge the following USGS employees for their contributions to the report and their thorough peer reviews: Jeff East, Liz Hittle, Marc Stewart, and Molly Wood. Appreciation is extended to Sonny Anderson, Hugh Darling, and Jon Yokomizo for providing data, photos, and other information used in preparing this report. The authors also acknowledge assistance provided by Paul-Emile Bergeron, Jeanette Fooks, and Francois Rainville, Environment Canada. v Contents Acknowledgments ........................................................................................................................................iii Abstract ...........................................................................................................................................................1 Introduction.....................................................................................................................................................1 Purpose and Scope ..............................................................................................................................2 Applications of the Index Velocity Method ......................................................................................2 Previous Studies ...................................................................................................................................2 Introduction to the Index Velocity Method ................................................................................................3 Site and Instrument Selection .....................................................................................................................3 Site Selection.........................................................................................................................................3 Instrument Selection ............................................................................................................................6 ADVM Installation and Configuration .........................................................................................................6 ADVM Installation .................................................................................................................................6 ADVM Configuration ..........................................................................................................................10 Selection of Measurement Volume for Sidelooker ADVMs ...............................................10 ADVM Frequency and Instrument Noise Level ...........................................................11 Boundary and Object Interference ................................................................................12 Flow Disturbance and Velocity Distribution .................................................................13 Setting the Measurement Volume .................................................................................14 Selection of Measurement Volume for Uplooker ADVMs ..................................................16 Measurement Interval and Averaging Period .......................................................................18 Initial Exploratory Time-Series Measurements ...........................................................19 Routine Time-Series Measurements .............................................................................20 Discharge Calibration and Validation Measurements ................................................20 Salinity and Coordinate Systems ............................................................................................22 Internally Stored and Transmitted Data .................................................................................22 Routine Field Techniques ............................................................................................................................23 Beam Checks .......................................................................................................................................23 Download and Review Internal Data ...............................................................................................26 Log File ..................................................................................................................................................26 ADVM Clock Check.............................................................................................................................26 Temperature Check ............................................................................................................................26 ADVM Cleaning ...................................................................................................................................26 ADVM Alignment.................................................................................................................................27 Reconfigure the ADVM ......................................................................................................................27 Start Date and Start Time ..................................................................................................................27 Re-Deploy the ADVM .........................................................................................................................27 Routine Office Techniques .........................................................................................................................27 Velocity Data ........................................................................................................................................27 ADVM Water Temperature ................................................................................................................28 Cell End .................................................................................................................................................28 Signal-to-Noise Ratio .........................................................................................................................28 Rating Development and Analysis ............................................................................................................28 Stage-Area Rating ..............................................................................................................................29 vi The Standard Cross Section ....................................................................................................29 Cross-Section Survey ...............................................................................................................29 Stage-Area Rating Development ............................................................................................30 Stage-Area Rating Validation ..................................................................................................34 Discharge Measurement Calibration Data ..............................................................................................34 Index Velocity Rating ...................................................................................................................................35 Data Compilation .................................................................................................................................35 Rating Development and Analysis ...................................................................................................38 Graphical Data Analysis ...........................................................................................................39 Simple-Linear Regression Rating ............................................................................................42 Rating Development .........................................................................................................42