Sediment Acoustics

Science Center Objects

The U.S. Geological Survey recognizes the need to provide sediment acoustic training and to develop standardized techniques and practices.

The multi-agency Sediment Acoustic Leadership Team (SALT) develops technical guidance and training for using acoustic metrics to monitor aquatic sediment. The SALT provides assistance and guidance regarding all aspects of the development and use of hydroacoustic instrumentation for monitoring characteristics of aquatic sediment, with a focus on  fluvial environments. 

 

Continuous Time-Series Methods

Suspended sediment characteristics relate functionally to acoustic backscatter and attenuation. Continuous time-series suspended-sediment concentration (SSC) is obtained using continuous time-series acoustic metrics from fixed-place, in situ acoustic Doppler velocity meter (ADVM) data and a calibrated and approved acoustic-SSC index rating. These sections describe and utilize analytical methods to normalize measured acoustic backscatter data for several factors to isolate the attenuation and backscatter that is driven by sediment characteristics.

Software

Guidance

Training

 

Discrete Measurement Methods

A method for the measurement of high spatial and temporal resolution suspended-sediment concentration (SSC) using a down-looking acoustics is in development. The high-resolution scales of sediment data are a primary advantage and a vast improvement over other discrete methods for measuring SSC. Although acoustic surrogate technology using continuous, fixed-deployment ADCPs (side-looking) is proven, the same methods cannot be used with down-looking ADCPs due to the fact that the SSC and particle-size distribution variation in the vertical profile violates theory and complicates assumptions.

Software

Sediment Transect Acoustics (STA) software

A software tool is being developed to assist in using acoustic backscatter from a down-looking, mobile ADCP as a surrogate for SSC. This tool has a simple graphical user interface that loads the data, assists in the calibration procedure, and provides data visualization and output options. This tool is designed to improve ongoing efforts to monitor and predict resource responses to a changing environment. Because ADCPs are used routinely for streamflow measurements, using acoustic backscatter from ADCPs as a surrogate for SSC has the potential to revolutionize sediment measurements by providing rapid measurements of sediment flux and distribution at spatial and temporal scales that are far beyond the capabilities of traditional physical samplers.

The software is called Sediment Transect Acoustics (STA) and the following are some highlights:

  • Software to assist in processing ADCP and SSC data from vertical profiles
  • To calibrate acoustic backscatter with suspended sediment concentration
  • For computing total SSC and sediment load
  • High-spatial resolution visualizations

Summary

From Mobile ADCP to High-Resoulution SSC: A Cross-Section-Calibration Tool

Collaboration

Sediment Acoustics

Collaboration on analyzing available data or collecting new dataset is possible. These datasets can be used to test assumptions and answer key questions in the use of down-looking ADCPs to estimate suspended sediment.

The required dataset would include (see figure above and list below):

  • Point, isokinetic sediment samples
  • Concurrent ADCP stationary profiles at each sampling vertical
  • Moving-boat ADCP measurements
  • Depth-integrated, isokinetic EDI samples

Please contact Molly Wood (mswood@usgs.gov), Justin Boldt (jboldt@usgs.gov), or Tim Straub (tdstraub@usgs.gov) if you have existing monitoring programs with sediment and ADCP datasets that meet or can be adapted to meet these requirements.

 

Documents and References

Fact Sheet

Techniques and Methods

Memos and Notes

  • SW 12.05 - Creation of the Sediment Acoustic Leadership Team (SALT)

Site studies sources

Theory and Methods sources

 

Training

Ongoing or Upcoming Training

Past Workshops

  • Workshop at the 10th Federal Interagency Sedimentation Conference - 4/23/2015
  • Workshop at the USGS Data Conference - 09/08/2014
  • Workshop at the National Water Quality Monitoring Conference - 04/28/2014
     

Forum

USGS Suspended-Sediment Concentration Forum

The forum is maintained by the U.S. Geological Survey (USGS) for sharing information regarding the application of surrogates to the measurement of suspended-sediment concentration. The forum is a USGS resource to educate, learn, and facilitate the exchange of information about applications involving a variety of instruments including acoustics, turbidity, laser diffraction, and other technologies. The forum is also used by the USGS to disseminate important information regarding quality assurance practices, training, and other matters.

Registration is required to access the forum.

Number of streamgages per state where suspended-sediment and acoustic data are collected.

Demonstration Sites

Ongoing

USGS 13342500 Clearwater River at Spalding, Idaho

USGS 01648010 Rock Creek at Joyce Road, Washington DC

USGS 08067252 Trinity River at Wallisville, Texas

USGS Grand Canyon Monitoring and Research Sites
 

Historic

USGS 13213000 Boise River near Parma, Idaho