Investigation of Hydroacoustic Flow-Monitoring Alternatives at the Sacramento River at Freeport, California: Results of the 2002-2004 Pilot Study

By Catherine A. Ruhl and James B. DeRose


Scientific Investigations Report 2004-5172

Sacramento, California 2004

Prepared in cooperation with the Sacramento Regional Wastewater Treatment Plant and the California Department of Water Resources

Complete accessible text of report (2.6 MB PDF)

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     The Sacramento River at Freeport is a tidally affected channel approximately 620 feet wide located at the northern boundary of the Sacramento—San Joaquin River Delta, California. In 1978, an acoustic velocity meter was installed at Freeport to monitor the flow. The acoustic velocity meter was calibrated successfully and has been used continuously since that time. Although the calibration has been extremely stable, an increasing number of maintenance problems prompted a search for alternatives to monitor discharge at this location. Two sideward-looking acoustic Doppler velocity meters were tested in a pilot study from 2002-2004: a short-range system and a long-range system. The pilot study was conducted over a wide range of hydrologic conditions and both sideward-l-ooking acoustic Doppler velocity meters have performed well at this location and have been calibrated successfully. As of February 2004, the short-range system had a robust calibration and a higher data-recovery rate, therefore, it was selected as the primary replacement of the acoustic velocity meter, with the long-range system providing real-time data redundancy to minimize data loss.


Executive Summary



Purpose and Scope


Principles of Operation of Acoustic Flow-Monitoring Systems

Acoustic Velocity Meter

Acoustic Doppler Velocity Meter

Calculation of Discharge

Equipment Configuration

Acoustic Velocity Meter

Short-Range Acoustic Doppler Velocity Meter

Long-Range Acoustic Doppler Velocity Meter

Downward-Looking Acoustic Doppler Current Profiler

Proof-of-Concept Study


Area Calibration

Velocity Calibration

Acoustic Velocity Meter

Short-Range Acoustic Doppler Velocity Meter

Long-Range Acoustic Doppler Velocity Meter

Outfall Building Datalogger Programming and Error-Checking Algorithm

Data Transmission

Cellular Digital Packet Data

Radio Signal




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Water Resources of California

U.S. Department of the Interior, U.S. Geological Survey
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