We introduce a methodology for a comprehensive characterization of river flows from transects surveyed at different times over near coincident transects from acoustic Doppler current profiler (ADCP) data acquired from a moving vessel.
The ADCP measurements are first rotated from East and North velocities into primary and secondary flows that are projected onto a grid of points on an ideal transect. This approach allows computing of time and spatial averages of ADCP velocities from which mean velocity, turbulence fluctuation, spectral power density and vorticity can be quantified. It also provides a foundation for a comprehensive river characterization analysis which allows for improvements in our understanding of sediment transport and riverbed conditions, strategies for debris avoidance, and fish studies.
A case study with a data set from the Tanana River in Nenana, Alaska is presented. ADCP measurements are processed through the algorithm and results interpreted. ADV measurements are then used to compute energy spectra and integral length scale which agrees with the largest eddy size in the inertial subrange of the ADCP data.