Qualitative and quantitative acoustic mapping of bedform dynamics

• A new measurement concept to assess the bedform dynamics is introduced.
• Acoustic survey combined with image technique is shown to estimate bedform dynamics.
• The combination of techniques is fit for application in laboratory and field sites.

The qualitative and quantitative assessment of bedform dynamics has been a continuous challenge for conventional river monitoring methods due to the vexing problems associated with the limited capabilities to observe the bedforms in-situ and the intrusive nature of the instruments used for quantification of their movement. The advent of the new generation of acoustic- and image-based instruments has brought considerable promise for the experimental investigations in this area by allowing observations of the bedforms from close range along with possibilities of non-intrusive quantification of their movement with unprecedented spatial and temporal resolutions.This paper reports proof-of-concept tests for quantifying the dynamics of the bedform migration using a combination of concepts from two representatives of the new nonintrusive instruments: acoustic survey and processing techniques associated with particle image velocimetry. Given the combination of mapping and velocimetry operating principles, we call the technique acoustic mapping velocimetry (AMV). This hybrid technique has potential to track the planar migration of the bedform and quantify the velocity of the moving bedform fronts. Described herein is a laboratory experiment illustrating the implementation of the AMV concept for quantifying bedform migration.