In Reply Refer To:
Mail Stop 415
May 30, 2012
OFFICE OF SURFACE WATER TECHNICAL MEMORANDUM 2012.05
SUBJECT: Creation of Sediment Acoustic Leadership Team (SALT)
Methods are rapidly advancing to estimate sediment characteristics in aquatic systems using acoustic backscatter and attenuation. The advantages of hydroacoustic metrics as surrogates of suspended sediment include greater accuracy due to high temporal resolution, a larger sample volume, and increased environmental robustness over conventional sediment sampling and monitoring techniques, plus hydroacoustic surrogate techniques use a technology that is now ubiquitous in streamflow monitoring and that yields a simultaneous velocity measurement. This approach has proven effective for continuous monitoring of suspended-sediment concentrations in several environments.
Hydroacoustic surrogates also have potential applications for estimating particle-size categories, bedload, and bed-material composition. A few Water Science Centers (WSC) are developing sediment surrogate relations using acoustic metrics, and there is significant program potential. Some example applications, presented in a recent workshop, may be viewed at: water.usgs.gov/fisp/research.html.
There are, however, impediments to the widespread adoption of hydroacoustic surrogate techniques. Generalized best methods have not been determined for measuring acoustic attenuation and adjusted backscatter amplitude, nor for using this information to compute suspended sediment concentration and other sediment characteristics. Also, backscatter metrics are not uniformly reported by different hydroacoustic instruments.
The Office of Surface Water (OSW) recognizes the need to develop guidance, standardized techniques, and training. In order to meet these needs, OSW is establishing the Sediment Acoustic Leadership Team (SALT). The SALT is patterned after, and will operate with consultation from the OSW Hydroacoustics Workgroup (HaWG) and closely coordinate with the Office of Water Quality (OWQ) Continuous Water Quality Committee (CWQC).
The purposes of the SALT are to:
Membership of the SALT is composed of USGS personnel (up to 12) and selected representatives from other federal agencies and/or academia. The Charter members are: Mark Landers, Chair (OSW), David Mueller (OSW), Scott Wright (California WSC), Tim Straub (Illinois WSC), Molly Wood (Idaho WSC), Pat Dickhudt (Massaschusetts, Woods Hole), Cory Williams (Colorado WSC), Mike Lee (Texas WSC), Ryan Jackson (Illinois WSC), Dan Dombroski (U.S. Bureau of Reclamation, Colorado), and Tim Calappi (U.S. Army Corps of Engineers, Detroit District).
A Sediment Surrogates Forum board for has been set up on OSW Forums (https://simon.er.usgs.gov/smf/index.php). This new forum will be used to communicate questions, activities, and findings in acoustic and other sediment surrogates. SALT members will monitor and respond to questions and comments posted on this Forum. Registration is required to access the forum. Detailed instructions on registering can be found at http://hydroacoustics.usgs.gov/software/Forum_Reg1.html. Please interact with the SALT and others on this forum as you consider and develop projects that utilize acoustic surrogates to estimate sediment.
Robert R. Mason, Jr.
Acting Chief, Office of Surface Water