Pacific Southwest

Title: Automatic real-time control of suspended sediment based upon high frequency in situ measurements of nephelometric turbidity

Author: Lewis, Jack; Eads, Rand

Date: 1998

Source: In: Gray, John, and Larry Schmidt (Organizers). Proceedings of the Federal Interagency Workshop on Sediment Technology for the 21st Century, 17-20 February 1998, St. Petersburg, FL.

Description: Abstract - For estimating suspended sediment concentration (SSC) in rivers, turbidity is potentially a much better predictor than water discharge. Since about 1990, it has been feasible to automatically collect high frequency turbidity data at remote sites using battery-powered turbidity probes that are properly mounted in the river or stream. With sensors calibrated to give a linear response to formazine standards, turbidity and sediment concentration should have a linear correlation close to unity for a given size and composition of suspended particles (Gippel, 1995; Foster et al., 1992). For events of limited duration, the physical properties of the suspended particles probably change very little in most streams. A few (less than 10) data pairs spanning the range of concentrations should be sufficient to reliably establish the relation between SSC and turbidity during such events (Lewis, 1996). This relationship provides a means for accurately estimating sediment loads during storm runoff events. In addition, the detailed turbidity record often contains the signature of sediment inputs to the channel from erosion and mass wasting (Lewis and Eads, 1996).

Keywords: PSW4351, Caspar Creek, turbidity, suspended sediment concentration, erosion, water discharge

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Citation

Lewis, Jack; Eads, Rand  1998.  Automatic real-time control of suspended sediment based upon high frequency in situ measurements of nephelometric turbidity.   In: Gray, John, and Larry Schmidt (Organizers). Proceedings of the Federal Interagency Workshop on Sediment Technology for the 21st Century, 17-20 February 1998, St. Petersburg, FL..