American Society of Civil Engineers

Correcting Acoustic Doppler Current Profiler Discharge Measurements Biased by Sediment Transport

by David S. Mueller, P.E., M.ASCE, (Hydro., Ofc. of Surface Water, U.S. Geological Survey, 9818 Bluegrass Pkwy., Louisville, KY 40229. E-mail: and Chad R. Wagner, P.E., A.M.ASCE, (Hydro., North Carolina Water Sci. Ctr., U.S. Geological Survey, 3916 Sunset Ridge Rd., Raleigh, NC 27607. E-mail:

Journal of Hydraulic Engineering, Vol. 133, No. 12, December 2007, pp. 1329-1336, (doi:

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Document type: Journal Paper
Abstract: A negative bias in discharge measurements made with an acoustic Doppler current profiler (ADCP) is attributed to the movement of sediment on or near the streambed, and is an issue widely acknowledged by the scientific community. The integration of a differentially corrected global positioning system (DGPS) to track the movement of the ADCP can be used to avoid the systematic bias associated with a moving bed. DGPS, however, cannot provide consistently accurate positions because of multipath errors and satellite signal reception problems on waterways with dense tree canopy along the banks, in deep valleys or canyons, and near bridges. An alternative method of correcting for the moving-bed bias, based on the closure error resulting from a two-way crossing of the river, is presented. The uncertainty in the mean moving-bed velocity measured by the loop method is shown to be approximately 0.6 cm/s. For the 13 field measurements presented, the loop method resulted in corrected discharges that were within 5% of discharges measured utilizing DGPS to compensate for moving-bed conditions.

ASCE Subject Headings:
Acoustic techniques
Discharge measurement
Flow measurement
Sediment transport