Author(s): Atsuhiro Yorozuya; Hiroshi Koseki; Shoji Okada; Takashi Kitsuta; Shun Kudo; Toshiharu Fueta
Linked Author(s):
Keywords: Coustic doppler current profiler; Multi-beam echo sounder; Bedload discharge; Effective shear velocity
Abstract: Most bedload formulas employ effective friction velocity to estimate bedload discharge rate. However, it is very difficult to measure effective friction velocity and its application to estimating bedload volume in an actual river. This has been an issue because until recently it is not possible to observe a wide area for a continuous period of time and also because no approaches have been available to verify effective friction velocity. In this study, a new method was introduced to verify effective friction velocity and evaluate the validity of bedload discharge estimated using the verified effective friction velocity in comparison with the results from an experiment using a Dcps and a multibeam echo sounder in an experimental flume nearly as large as an actual river. The study found that effective friction velocity can be verified by means of bottom track velocity from a Dcps and the bedload discharge rate created by Egashira et al. (1997; 2005). We also found that bedload volume estimated using effective friction velocity can successfully reproduce bedload calculated based on a horizontal riverbed height profile observed by a multibeam echo sounder.
Year: 2017