Availability of Flowtracker ADV

[Kevin Oberg]

As some of you may know, an Acoustic Doppler Velocimeter (ADV) has been 
adapted for use with a standard USGS wading rod for making shallow-water 
discharge measurements.  Recently, SonTek, the manufacturer, began to 
accept orders for this ADV, known as a Flowtracker Handheld ADV.

The Flowtracker was developed as a part of a USGS Instrumentation Committee 
(ICOM) project, with support from the Office of Surface Water (OSW).  The 
USGS provided guidance to SonTek in the adaptation of the ADV to wading 
measurements.  Guidance included supplying the manufacturer with standard 
USGS methods and algorithms for making discharge measurements.  The Indiana 
and Maryland-Delaware Districts of the USGS tested prototype 
instruments.  A prototype also was tested in the tow-tank at the OSW 
Hydraulics Laboratory, Stennis Space Center, Bay St. Louis, MS.  Testing 
results are available, along with other information on the project at 
http://in.water.usgs.gov/hydroacoustics/acoustic_wading_rod.shtml.

At present, no OSW policies have been prepared to provide guidance in the 
use of this instrument.  After final testing is completed, OSW will release 
recommendations in the form of an OSW technical memorandum and possibly a 
published report.  In the interim, our experience to-date indicates that 
present USGS discharge-measurement standards and procedures should be used 
when making discharge measurements with the Flowtracker.  The manufacturer 
describes suggested pre-measurement diagnostic procedures in the instrument 
manual.  If USGS personnel purchase a Flowtracker, OSW suggests that some 
comparison measurements with Price meters be made for quality-assurance 
quality-control purposes.

The location of the sampling volume (the volume of water in which velocity 
measurements are made) when using a Flowtracker is important.  The sample 
volume is located about 4 inches to the side of the wading rod.  The 
manufacturer currently is working on an adaptor bracket for a standard 
wading rod that would move the sample volume to within about 2 inches of 
the rod.  The bracket is being designed to keep the sample volume as close 
to the rod as possible while preventing measurements in areas affected by 
the flow disturbance created by the rod.  A sketch of the bracket is 
attached (Word format).  The adapter bracket is now available for sale, 
along with a bracket for mounting the data recorder on the top of the 
wading rod.

Intensive field-testing of the Flowtracker is scheduled to begin within the 
next two - three weeks.  At least five USGS District offices will 
participate in these tests.  The Flowtracker is also scheduled for 
production testing in the tow tank and jet tank at the OSW Hydraulics 
Laboratory on August 1, 2001.  Results of this testing will be posted to 
the project web page.

Questions or concerns may be addressed to Scott Morlock, Indiana District, 
(smorlock at usgs.gov), 317-290-3333 ext. 181.

(The use of trade or product names does not imply endorsement by the USGS).



Kevin Oberg
U.S. Geological Survey
Voice:	217.344.0037 extension 3004
Cell:	217.778.3235
http://il.water.usgs.gov/adcp/