Sediment Surrogate Techniques

USGS scientists typically collect sediment samples from multiple locations in a river using point, depth-, or time-integrating samplers. Sediment samples represent the sediment content in a particular river at a given point in time. To estimate sediment content at times when samples are not collected, scientists develop relations between sediment and other parameters, which might be measured more easily, safely, or cheaply than collecting a physical sample. These parameters are called “surrogates”.

Surrogate techniques evaluated for estimating suspended sediment include acoustic backscatter, turbidity, laser diffraction, and pressure difference. Surrogate techniques evaluated for estimating bedload sediment include bathymetric differencing, hydrophones, geophones, and impact plates. Selected USGS publications on these and other sediment surrogate techniques are listed below.

Additionally, the USGS has established the multi-agency Sediment Acoustic Leadership Team to advance the use of acoustic sediment surrogate techniques and provide associated guidance and training.

Selected publications relating to sediment surrogate techniques

Anderson, C.W., 2005, Turbidity (ver. 2.1): Techniques of Water-Resources Investigations of the U.S. Geological Survey, Book 9, Chapter A6, Section 6.7, September 2005, 55 p. This chapter of the USGS’s National Field Manual for the Collection of Water-Quality Data covers general procedures for the measurement of turbidity, which is often used as a surrogate measure of suspended sediment, particularly in rivers dominated by fine sediment sizes.

Wagner, R.J., Boulger, R.W., Jr., Oblinger, C.J., and Smith, B.A., 2006, Guidelines and standard procedures for continuous water-quality monitors—station operation, record computation, and data reporting: U.S. Geological Survey Techniques and Methods, Book 1, Chapter D3, 51 p., 8 attachments. This report presents methods for operating continuous water-quality monitors (sondes), including turbidity which is often used as a surrogate measure of suspended sediment. General protocols for measuring and calibrating turbidity are shown on pages 12-20. Recommended accuracy criteria for turbidity are shown on page 38.

Rasmussen, P.P., Gray, J.R., Glysson, G.D., and Ziegler, A.C., 2009, Guidelines and procedures for computing time-series suspended-sediment concentrations and loads from in-stream turbidity-sensor and streamflow data: U.S. Geological Survey Techniques and Methods, Book 3, Chapter C4, 53 p. This report describes procedures for estimating fluvial suspended sediment concentrations using turbidity probes deployed at a fixed location in a river or stream.

Anderson, C.W., and Rounds, S.A., 2010, Use of continuous monitors and autosamplers to predict unmeasured water-quality constituents in tributaries of the Tualatin River, Oregon: U.S. Geological Survey Scientific Investigations Report 2010-5008, 76 p. This report presents a case study for using turbidity as a surrogate for suspended sediment and other water-quality constituents. Surrogate models were developed using a combination of full cross-section, depth-integrated samples and automated unattended samples.

Gray, J.R., Laronne, J.B., Marr, J.D.G., 2010, Bedload-surrogate monitoring technologies: U.S. Geological Survey Scientific Investigations Report 2010–5091, 37 p. This report summarizes the applicability and state-of-the-art on technologies being tested as surrogates for bedload transport.

Wood, M.S., and Teasdale, G.N., 2013, Use of surrogate technologies to estimate suspended sediment in the Clearwater River, Idaho, and Snake River, Washington, 2008–10: U.S. Geological Survey Scientific Investigations Report 2013-5052, 30 p. This report describes some early efforts to use the side-looking acoustic backscatter method described in Landers and others (2016) to estimate suspended-sediment loads and develop sediment budgets for a navigational port.

Voichick, N., and Topping, D.J., 2014, Extending the turbidity record – making additional use of continuous data from turbidity, acoustic-Doppler, and laser diffraction instruments and suspended-sediment samples in the Colorado River in Grand Canyon: U.S. Geological Survey Scientific Investigations Report 2014-5097, 31 p. This report describes efforts to test multiple sediment surrogate technologies at a research site in the Colorado River.

Wood, M.S., 2014, Estimating suspended sediment in rivers using acoustic Doppler meters: U.S. Geological Survey Fact Sheet 2014-3038, 4 p. This fact sheet describes the overall concept of using backscatter from acoustic Doppler velocity meters (ADVMs) as a surrogate for fluvial suspended-sediment concentrations.

Boldt, J.A., 2015, From mobile ADCP to high-resolution SSC - A cross-section calibration tool: Proceedings of the 3rd Joint Federal Interagency Conference on Sedimentation and Hydrologic Modeling, April 19-23, 2015, Reno, Nevada, USA, 3 p. This USGS conference paper describes a developing method for using down-looking acoustic Doppler current profilers (ADCPs) to estimate suspended-sediment concentration and load in a river cross section.

Brown, J.E., Gray, J.R., Hornewer, N.J., 2015, In situ densimetric measurements as a surrogate for suspended-sediment concentrations: Proceedings of the 3rd Joint Federal Interagency Conference on Sedimentation and Hydrologic Modeling, April 19-23, 2015, Reno, Nevada, USA, 12 p. This USGS conference paper describes a surrogate densimetric method that has been successfully used to estimate very high fluvial suspended-sediment concentrations (typically >= 20,000 mg/L).

Czuba, J. A., T. D. Straub, C. A. Curran, M. N. Landers, and M. M. Domanski, 2015, Comparison of fluvial suspended-sediment concentrations and particle-size distributions measured with in-stream laser diffraction and in physical samples: Water Resour. Res., 51, pp. 320-340. This journal article (USGS authors) describes use of in-stream laser diffraction techniques to estimate fluvial suspended-sediment concentrations and particle sizes.

Domanski, M.M., Straub, T.D., and Landers, M.N., 2015, Surrogate Analysis and Index Developer (SAID) tool (version 1.0, September 2015): U.S. Geological Survey Open-File Report 2015-1177, 38 p. This report describes a software tool called SAID that is used by USGS to process data and develop calibrations for a number of sediment surrogate technologies, including the side-looking ADVM acoustic backscatter method described in Landers and others (2016) and the turbidity method described in Rasmussen and others (2009).

Mosbrucker, A.R. , Spicer, K.R. , Christianson, T.S. , and Uhrich, M.A., 2015, Close-range remotely-sensed multispectral imagery to quantify fine-grained suspended sediment: Proceedings of the 3rd Joint Federal Interagency Conference on Sedimentation and Hydrologic Modeling, April 19-23, 2015, Reno, Nevada, USA, 12 p. This USGS conference paper describes the use of commercially-available cameras to estimate fine-grained suspended-sediment concentrations through spectral analysis of the collected images.

Wood, M., Fosness, R., Pachman, G., Lorang, M., 2015, Evaluation of multi-frequency acoustics as a surrogate for bedload: Proceedings of the 3rd Joint Federal Interagency Conference on Sedimentation and Hydrologic Modeling, April 19-23, 2015, Reno, Nevada, USA, 11 p. This USGS conference paper describes efforts to test multi-frequency ADCPs and hydrophones for estimating various particle size fractions of bedload in a transitional zone in a gravel-bedded river with some sand in transport.

Landers, M.N., Straub, T.D., Wood, M.S., and Domanski, M.M., 2016, Sediment acoustic index method for computing continuous suspended-sediment concentrations: U.S. Geological Survey Techniques and Methods, Book 3, Chapter C5, 63 p. This report describes standard USGS procedures for estimating fluvial suspended-sediment concentrations using backscatter from single-frequency, side-looking ADVMs deployed at a fixed location in a river or stream.

Topping, D.J., and Wright, S.A., 2016, Long-term continuous acoustical suspended-sediment measurements in rivers – Theory, application, bias, and error: U.S. Geological Survey Professional Paper 1823, 98 p. This report describes procedures for estimating fluvial suspended sediment concentrations using backscatter from multiple-frequency, side-looking ADVMs deployed at a fixed location in a river or stream. This method is particularly applicable to river sites that have bimodal or varying sediment particle size distributions over space and time.