Multi-year deployment of a single frequency high-frequency acoustic attenuation system for measuring fine suspended sediments in stream channels

Authors: CARPENTER, WAYNE - University Of Mississippi; GOODWILLER, BRADLEY - University Of Mississippi; Wren, Daniel

Submitted to: International Journal of Sediment Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/5/2025
Publication Date: 6/9/2025
Citation: Carpenter, W.O., Goodwiller, B.T., Wren, D.G. 2025. Multi-year deployment of a single frequency high-frequency acoustic attenuation system for measuring fine suspended sediments in stream channels. International Journal of Sediment Research. https://doi.org/10.1016/j.ijsrc.2025.06.005.
DOI: https://doi.org/10.1016/j.ijsrc.2025.06.005

Interpretive Summary: Measurement of sediment concentrations is necessary for management of streams and rivers. Instrumentation that uses sound for sediment measurements is useful because it is inexpensive relative other measurement technology, it works in cloudy water, and it is typically not affected by algae growing the sensor surfaces. Acoustic instrumentation allows for continuous measurements, since they can work automatically with a computer controlling the instrument, reducing the need for personnel to be on site during potentially hazardous condition or at night. Fine sediments in rivers and streams, which can be seen in the brown-colored water present in many waterways, can be measured by comparing the amount of acoustic signal that travels between sensors in clear water to the signal through water with suspended sediment particles. This manuscript describes a three-year deployment of a system that uses acoustic attenuation, which is reduction in signal strength, to measure the amount of fine particles transported through Goodwin Creek, near Batesville, MS. We showed that the acoustic device was able to measure sediment concentrations over a range of flow events, and the acoustic data agreed well with sediment concentrations based on physical samples collected at the same time as the acoustic data. The acoustic system was able to identify details of sediment transport that could not be detected using standard pump sample methods. The system was shown to be reasonably robust by showing data for 14 flow events, only suffering damage after being impacted by a large tree that was carried downstream during high flows. The technology described in this manuscript is already being used by ARS to improve monitoring of sediment movement in Goodwin Creek, and, after continued development of the method, it is anticipated that monitoring agencies such as the U.S. Geological Survey will use the device for field measurements.

Technical Abstract: The National Center for Physical Acoustics (NCPA) at The University of Mississippi has developed a single frequency acoustic attenuation system (SFAAS) to monitor the concentration of suspended fine sediments in rivers and streams. The system was operated in the Goodwin Creek Watershed in Panola County, Mississippi, from November 2019-Februray 2023. The system collected data when stream stage was above 0.3 m, and physical pump samples were collected concomitantly to provide calibration data. A subset of the data, comprising 14 storm events recorded over the multi-year deployment, will be presented here to demonstrate the operation of the SFAAS and its potential to aid in hydrologic research. It was found that the SFAAS was able to provide high-resolution fine sediment concentration data with a stable calibration relation for a given hardware configuration. The data was used to investigate the behavior of fine sediment concentrations in the watershed, including hysteresis in the relationship between flow rates and sediment concentrations during streamflow hydrographs and sediment rating curves that relate stream depth to transport rates.