In Reply Refer To:
Mail Stop 415

September 29, 2005


SUBJECT: Classifying Measurement Type in the Automated Data Processing System (ADAPS)

With the advent of acoustic Doppler technology for making discharge measurements, some confusion has arisen regarding classification of measurements in the Automated Data Processing System (ADAPS). Traditionally, a mechanical current meter was used and the classification of discharge measurements was based on the type of suspension used for the current meter (bridge, cableway, wading, ice, etc.); not on the current meter type. However, there is now a need to be able to classify and differentiate discharge measurements based on the type of instrument used to determine velocity, primarily to better track the ever increasing use of hydroacoustics.

This memorandum establishes the policy for discharge measurement classification in ADAPS beginning with the 2006 Water Year. In ADAPS version 4.5, a code was added for measurements made with Acoustic Doppler Velocimeters (ADVs, generally FlowTrackers). This code is in addition to the already existing code for acoustic Doppler current profilers (ADCPs). The required classification is that any measurements made via acoustic technology be coded as either ADCP or ADV, regardless of suspension. The type of suspension used for an acoustic technology measurement (boat, tethered boat, permanent installation, wading rod) should be noted in the remarks. The codes for wading, handline, bridge, cableway, boat, and ice should continue to be used as appropriate for traditional mechanical Price (AA or pygmy) current meter measurements. The codes for flume, estimated, and indirect discharge measurements should be used as appropriate for those types of measurements.

This policy is effective starting with measurements made on October 1, 2005 or later. USGS Water Science Centers are encouraged, but not required, to reclassify hydroacoustic measurements made prior to the creation of the ADV code. Future versions of ADAPS are planned to allow for a combination of codes to better classify discharge measurements based on both instrument type and method of suspension.


Stephen F. Blanchard
Chief, Office of Surface Water

WRD Distribution: All Water Employees