Title: Estimating Bedload in Sand‐Bed Channels Using Bottom Tracking from an Acoustic Doppler Profiler
Abstract: A method to estimate bedload in sand-bed rivers using bottom tracking from an acoustic Doppler profiler (ADP) is outlined and tested. The velocity of a mobile sand bed is related to the difference between the 'apparent' boat velocity with respect to the bed measured with ADP bottom tracking and the 'actual' boat velocity measured with a differential global positioning system (DGPS). Under simple assumptions the velocity of a mobile sand bed can be converted to an estimate of bedload. Estimates of bedload using this method were acquired from a launch anchored over the upper stoss face of large sand dunes in the Fraser River, British Columbia. These estimates are compared with measurements from a Helley–Smith sampler and predictions from the Van Rijn bedload formula. All three methods produce consistent and comparable values. Near concordance was observed between the mechanical and acoustic estimates of bedload transport, although with a large degree of scatter, indicating that both instruments are measuring similar fractions of near-bed transport. In comparison, the correlation with computed transport, although stronger, was more strongly biased. Part of the difficulty in reconciling the measurements lies in the arbitrary nature of the division between 'bedload' and near-bed suspension in transport over a sand bed. Within this constraint, ADP technology shows potential to yield remote measurements of bedload in sand-bed channels, escaping the limitations of mechanical samplers.
Publication Year: 2005
Publication Date: 2005-02-15
Language: en
Type: other
Indexed In: ['crossref']
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Cited By Count: 12
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