Skip Links

USGS - science for a changing world

Techniques and Methods 3–C4

Guidelines and Procedures for Computing Time-Series Suspended-Sediment Concentrations and Loads from In-Stream Turbidity-Sensor and Streamflow Data

Chapter 4 of
Book 3, Applications of Hydraulics
Section C, Sediment and Erosion Techniques

By Patrick P. Rasmussen, John R. Gray, G. Douglas Glysson, and Andrew C. Ziegler

Thumbnail of and link to report PDF (3.5 MB)


In-stream continuous turbidity and streamflow data, calibrated with measured suspended-sediment concentration data, can be used to compute a time series of suspended-sediment concentration and load at a stream site. Development of a simple linear (ordinary least squares) regression model for computing suspended-sediment concentrations from instantaneous turbidity data is the first step in the computation process. If the model standard percentage error (MSPE) of the simple linear regression model meets a minimum criterion, this model should be used to compute a time series of suspended-sediment concentrations. Otherwise, a multiple linear regression model using paired instantaneous turbidity and streamflow data is developed and compared to the simple regression model. If the inclusion of the streamflow variable proves to be statistically significant and the uncertainty associated with the multiple regression model results in an improvement over that for the simple linear model, the turbidity-streamflow multiple linear regression model should be used to compute a suspended-sediment concentration time series. The computed concentration time series is subsequently used with its paired streamflow time series to compute suspended-sediment loads by standard U.S. Geological Survey techniques.

Once an acceptable regression model is developed, it can be used to compute suspended-sediment concentration beyond the period of record used in model development with proper ongoing collection and analysis of calibration samples. Regression models to compute suspended-sediment concentrations are generally site specific and should never be considered static, but they represent a set period in a continually dynamic system in which additional data will help verify any change in sediment load, type, and source.

Posted June 25, 2009

For additional information contact:
Director, USGS Kansas Water Science Center
4821 Quail Crest Place, Lawrence, KS
(785) 842–9909

Part or all of this report is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge.

Suggested citation:

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, chap. C4, 53 p.




Types of Turbidity Sensors

Relation of Turbidity to Suspended-Sediment Concentration

Computation of Suspended-Sediment Concentration and Load Time-Series Record



Selected References

Appendix 1. Examples of Suspended-Sediment Concentration Models from Kansas, Oregon, Florida, and California

Appendix 2. Computation, Storage, and Real-Time Display of Time-Series Suspended-Sediment Concentrations and Loads in National Water Information System

Appendix 3. Comparison of Computed Suspended-Sediment Concentrations with Water-Quality Criteria

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo logo U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information: GS Pubs Web Contact
Page Last Modified: Friday, 02-Dec-2016 15:48:50 EST