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

Project Progress

This section documents project progress as of April 3, 2001.

ADV 

In August 2000, the USGS Indiana District office took delivery of a custom ADV manufactured by SonTek Corporation designed for wading discharge measurements. A standard top-setting wading rod was adapted for the ADV. The ADV had a custom 2D/3D probe head, an external power-supply box, and and a hand-held PC with custom software that allowed the input of subsection stations and depths. This unit is considered a proof-of-concept (POC) prototype. Discharge measurements with the POC ADV began soon after delivery. Discharge measurements with mechanical current meters were made concurrently for comparison with the POC ADV discharge data.

USGS Hydrographer making a wading discharge measurement using the proof-of-concept ADV.

Discharges from the ADV measurement appeared to be biased low, compared to mechanical-meter discharges. The ADV appeared to be measuring velocities correctly, so the bias was likely within the data-processing software used by the hand-held interface. Despite the software issue, the POC ADV established that:

• A custom ADV can be mounted on a standard-top setting wading rod;
• The standard area-velocity method of making wading discharge measurements can be used with an ADV; and
• An ADV will measure water velocities in depths as shallow as 1 inch.

On January 22, 2001, SonTek representative Craig Huhta delivered a new ADV prototype to the Indiana District and participated in testing of the new instrument. The new ADV prototype has been improved over the POC prototype for the wading-rod application. This "second-generation" prototype is an intermediate model between the POC prototype and the first commercially available units that SonTek plans to offer.  The purpose of the second-generation prototype is USGS testing - testing intended to produce data and suggestions that SonTek can use to refine ADV design and features for development. New features of the second-generation prototype follow.

• The probe head is detached from the ADV electronics.
• The ADV electronics and power supply are integrated within an interface that includes a keypad for entering discharge-measurement parameters and a LCD screen for displaying information; the probe head is attached to this interface by a cable.
• The probe head has a mounting peg that allows it to be attached quickly to a standard wading rod.
• The interface allowed entry of the basic parameters required to make a discharge measurement: station, distance, depth, and vertical location of the measurement (0.6, or 0.2 and 0.8 of the depth).
• The interface displayed computed discharge at the end of a measurement.
• Several files for each measurement were stored on the interface, including a discharge summary and raw-data file.
• The discharge-computation algorithms were based on USGS standards for discharge measurements.

Second-generation ADV prototype probe head.

Second-generation ADV interface box that contains a keyboard, display screen, ADV electronics and power supply.

Field testing of the second-generation ADV prototype was conducted in Indiana the week of January 22, 2001, and laboratory testing ("technical evaluation") was conducted on February 1 at the USGS Hydraulics Laboratory at Stennis Space Center, Mississippi.

Summary of field testing

Summary of technical evaluation

Profiler  

In July 2000 the Nortek Corporation requested the assistance of the Indiana District office in a test of the company's Aquadopp for wading discharge measurements. Aquadopp was tested at a USGS streamflow-gaging station in August 2000 on a stream in the Indianapolis Metropolitan Area. The Aquadopp was mounted temporarily on a tethered boat developed for a moving-platform Doppler current meter application. Data communication between the Aquadopp and the manufacturer's data-acquisition software was provided by a pair of radio modems. The Aquadopp was manually floated from subsection to subsection. At each subsection, data were collected for 5 minutes. Nortek personnel post-processed the data to compute discharge, using standard extrapolation methods to estimate discharge in the unmeasured zones. The discharge computed from the Aquadopp data was 63.8 cubic feet per second (ft³/s), while the discharge computed from USGS standard conventional methods was 63.0 ft³/s.

Trial of profiler wading discharge measurement.

The USGS Indiana District office had purchased an Aquadopp profiler for research purposes. Based on the results of this test, this profiler was modified for the wading-discharge-measurement project. Nortek suggested a custom transducer head for this application. The head would give the Aquadopp the potential to operate in depths as shallow as 6 inches. 

Custom profiler transducer head.
Graphic courtesy of Nortek Corporation.



Conceptual sketch of profiler for making wading discharge measurements.
Graphic courtesy of Nortek Corporation.

The red line in the conceptual sketch indicates transmitted pulses for depth measurement. The blue lines indicate the path of sound pulses from various transducers. The green lines indicate the borders of depth cells. Of special note is the "forward looking" transducer that would transmit sound pulses at a shallow angle for shallow depths (represented in the sketch by the single blue line with five depth cells).

In December 2000, the Indiana District received the Nortek proof-of-concept (POC) profiler integrated with the custom transducer head for the profiler application.  Nortek supplied software modules so that Indiana District personnel can begin work on data-collection programs for a field computer.  The District also received a prototype "boogy board" floating platform from the OceanScience Group; this platform will be used to float the profiler during data collection on streams. 

Proof-of-concept profiler mounted to floating platform to be used for field tests.

Next: Project Plans

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
5957 Lakeside Boulevard
Indianapolis, Indiana
46278-1996
USA
Phone: (317)290-3333
Fax: (317)290-3313
URL: http://sunrise.er.usgs.gov/hydroacoustics/acoustic_wading_rod_progress.shtml
Last modified:Monday, 13-Aug-2007 15:58:47 EDT
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