Development and calibration of an underwater acoustic data collection system for monitoring coardse bedload transport

Authors: GOODWILLER, BRADLEY - University Of Mississippi; Wren, Daniel; SURBECK, CRISTIANE - University Of Mississippi

Submitted to: Applied Acoustics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/14/2019
Publication Date: 12/1/2019
Citation: Goodwiller, B.J., Wren, D.G., Surbeck, C. 2019. Development and calibration of an underwater acoustic data collection system for monitoring coardse bedload transport. Applied Acoustics. 155 (2019):383-390. https://doi.org/10.1016/j.apacoust.2019.06.019.
DOI: https://doi.org/10.1016/j.apacoust.2019.06.019

Interpretive Summary: The measurement of sediment transported on and near the bed of streams and rivers is an important need for river management, particularly when dams are removed, which creates a need for measuring the release of stored coarse sediments. The collection of bed load samples is very difficult and expensive, making the continued development of instrumentation necessary. Using underwater microphones to record the sounds of rocks impacting one-another is a promising, low-cost method that may lead to a useful measurement technique for bed load measurement. The work described here is the detailed development, testing, calibration, and deployment of a system for recording the sound that gravel particles make when the hit each other in a stream. The only way to ensure that the data can be compared is by carefully calibrating the acoustic system to know standards. The goal of the work is to provide guidance for others who are studying the use of sound for bed load measurement so that data collected by different groups will be comparable. The U.S. Bureau of Reclamation has actively supported this work, since it aids efforts to improve the ability to monitor the movement of coarse sediments in streams.

Technical Abstract: Acoustic technology has potential as a surrogate method for monitoring coarse bed load transport in rivers and streams. This has been demonstrated by both laboratory experiments and field studies where it was found that acoustic energy generated by particle collisions was proportional to the amount of bed load in transport. One factor that has inhibited further development of the technique is that comparison of acoustic data is complicated by the wide variety of hardware used to collect it. A second factor is the need for each research group to assemble hardware, which is often expensive and designed for laboratory use. In addition, the hardware used in the field is rarely calibrated to an absolute parameter. The purpose of this manuscript is to present an inexpensive acoustic system that can be assembled from readily available equipment and to thoroughly investigate the operational parameters of the system through laboratory testing and field deployments. The following are presented here: assembly of the system, major operating parameters, system calibration, and multiple deployment techniques.