Hydroacoustic Current Meters for the Measurement of Discharge in Shallow Streams and Rivers

Field testing of second-generation ADV prototype

Field testing of the second-generation ADV wading-rod prototype consisted of making discharge measurements at eight USGS streamflow-gaging stations. One ADV discharge measurement was made per station. A mechanical current meter (conventional) discharge measurement was made concurrently for comparison. The same tag line and stations were used for both measurements, to the extent possible. 

Concurrent ADV and conventional discharge measurements

The following table is a summary of the discharge-measurement tests.

[ADV, acoustic Doppler velocimeter; ft, foot; ft², square foot; ft/s, foot per second; ft³/s, cubic foot per second; all data are provisional and subject to revision]

Stream conditions varied from site to site: water velocities ranged from nearly zero to more than 25 ft/s, depths from 0.2 to 2.8 ft, and streambed conditions ranged from rocky to smooth and sandy. The following conclusions were drawn from the tests:

• The discharge-computation algorithms appear to be correct.
• Analysis of the data indicated that channel areas differed by as much as 9 percent between ADV and conventional for some measurements; because duplicate stationing was used, these differences appear to be depth-reading errors.
• Only one ADV and one conventional measurement were made per station – in future testing, two conventional  measurements per site will be made where possible in case a meter had any bias errors.  Performing a second ADV measurement also would be prudent for repeatability.
• The  ADV sampling volume is about 4 inches to the side of the wading rod, which could impact measurement accuracy on smaller streams.  Plans are for commercially available units to have the probe attached to the wading rod so that the sampling volume is closer to the rod.

Indiana District Hydroacoustics Main Page
Office of Surface Water Hydroacoustic Support Pages

• The use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the United States Government.
• All information herein is provisional and subject to revision.
• Emphasis on the instruments described in these pages does not imply that these are the only instruments that can be used for this purpose. The instruments were selected for the following reasons: the instruments are readily adaptable to this purpose, the instruments are on Federal purchase schedules, and the instrument vendors have voluntarily committed resources to this application. Other instruments will be investigated within the limits of project funding and schedules.

U.S. Department of the Interior
U.S. Geological Survey
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Indianapolis, Indiana
46278-1996
USA
URL: http://sunrise.er.usgs.gov/hydroacoustics/acoustic_wading_rod_fieldtests.shtml
Last modified:Monday, 13-Aug-2007 15:58:48 EDT
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