Relevance of acoustic methods to quantify bedload transport and bedform dynamics in large sandy-gravel bed river

Abstract. Despite the inherent difficulties to quantify its value, bedload transport is essential to understand fluvial systems. In this study, we assessed different indirect bedload measurement techniques with a reference direct bedload measurement in a section of a large sandy-gravel bed river. Acoustic Doppler Current Profiler (aDcp), Dune Tracking Method (DTM) and hydrophone measurement techniques were used to determine bedload transport rates using calibration with the reference method or using empirical formula. Results show that the hydrophone is the most efficient and accurate method to determine bedload flux in the Loire River. Even though parameters controlling self-generated noise of sediments still need to better understood, the calibration determined in this study allows a good approximation of bedload transport rates. Moreover, aDcp and hydrophone measurement techniques are both able to continuously measure bedload transport associated to bedform migration.