Ramooz, Rauf2013-11-072013-11-0720072007Source: Masters Abstracts International, Volume: 46-03, page: 1635.http://hdl.handle.net/10393/27482http://dx.doi.org/10.20381/ruor-18730Moving bottom bias in acoustic Doppler current profiler (ADCP) bottom tracking has been used as an estimate of apparent bedload velocity (Rennie et al., 2002). However, it remains unknown if the apparent bedload velocity is an unbiased estimate of average bedload particle velocity. This paper presents a controlled laboratory calibration of ADCP bedload velocity, which was performed in the Main Test Channel at the St. Anthony Falls Laboratory as part of the National Centre for Earth-Surface Dynamics SedT project. The length of the sediment-recirculating mobile bed test section was 20 m. Both sand-bed (d50 = 0.98 mm) and gravel-bed (d50 = 11.06 mm) bedload transport experiments were conducted, with five flow rates tested for each sediment. Bottom track data were collected with both 600 and 1200 kHz Rio Grande ADCPs, and over a range of bottom track pulse lengths (&R20 to &R40). Actual bedload transport rates were measured using (1) conventional samplers, (2) five automatic weigh pans spread across the channel at the end of the test section, (3) dune tracking by means of eight sonars, and (4) high speed digital videography. In this paper, measured apparent bedload velocity is compared to bedload transport rate from the weigh pans and dune tracking. In addition, the influence of bottom track pulse length and operating frequency on measured bedload velocity is assessed. The results show correlation between ADCP bottom tracking and measured bedload transport rates, with coefficient of determination (r 2) ranging from 0.59 to 0.93 with RMSE (root mean square error) ranging from 0.059 m/s to 0.106 m/s for sand bed. For the gravel bed, correlation was found between capture rates and dune tracking with r2 0.52 to 0.97; however, the results were scattered. Initial experimental test results verified that moving bottom bias in acoustic Doppler current profiler (ADCP) bottom tracking can be used as an estimate of bedload velocity. A comparison was achieved successfully with measured flux of capture rates and dune tracking transport rates. The preliminary results were promising for sand bed experiments; however for gravel bed it appears that the flow depths were insufficient for the operation of ADCP.205 p.enEngineering, Civil.Thesis