Open-File Report 2014–1204
Researchers at the U.S. Geological Survey, Cascades Volcano Observatory, investigated alternative methods for the traditional sample-based sediment record procedure in determining suspended-sediment concentration (SSC) and discharge. One such sediment-surrogate technique was developed using turbidity and discharge to estimate SSC for two gaging stations in the Toutle River Basin near Mount St. Helens, Washington. To provide context for the study, methods for collecting sediment data and monitoring turbidity are discussed. Statistical methods used include the development of ordinary least squares regression models for each gaging station. Issues of time-related autocorrelation also are evaluated. Addition of lagged explanatory variables was used to account for autocorrelation in the turbidity, discharge, and SSC data. Final regression model equations and plots are presented for the two gaging stations. The regression models support near-real-time estimates of SSC and improved suspended-sediment discharge records by incorporating continuous instream turbidity. Future use of such models may potentially lower the costs of sediment monitoring by reducing time it takes to collect and process samples and to derive a sediment-discharge record.
First posted September 22, 2014
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Uhrich, M.A., Kolasinac, Jasna, Booth, P.L., Fountain, R.L., Spicer, K.R., and Mosbrucker, A.R., 2014, Correlations of turbidity to suspended-sediment concentration in the Toutle River Basin, near Mount St. Helens, Washington, 2010–11: U.S. Geological Survey Open-File Report 2014-1204, 30 p., https://dx.doi.org/10.3133/ofr20141204.
ISSN 2331-1258 (online)
Data Collection and Analysis Methods
Final Regression Models
Final Regression Model Graphs
Discussion and Future Studies
Appendix A. Suspended-Sediment Sample, Discharge, and Turbidity Data
Appendix B. Robustness Check Data