Surrogate Technologies for Estimating Suspended Sediment in the Snake and Clearwater Rivers

Science Center Objects

Because fluvial sediment poses both economic and ecological problems, resource managers need a safe, cost-effective way to measure sediment in streams, particularly in remote areas.

The USGS is leading research to evaluate technologies such as acoustic Doppler velocity meters (ADVMs), laser diffraction particle analyzer instruments, and optical turbidity monitors to indirectly measure sediment by measuring other, related parameters. Effective surrogate technologies are low-maintenance and robust over a range of hydrologic conditions. The parameters they measure can be modeled to estimate in real-time both sediment concentrations and the duration of elevated sediment levels.

Our research at two locations on the Snake River (at Anatone, WA) and the Clearwater River (at Spalding, ID) showed that:

  • Acoustic backscatter, measured by the ADVMs, had the best relation with physically measured suspended sediment concentrations.
  • Acoustic backscatter was less affected by biological fouling and could be measured in a larger part of the river channel than the other evaluated technologies.
  • Acoustic backscatter provides better estimates of suspended sediment concentrations and loads than traditional sediment transport curves based on streamflow.
  • Sediment surrogate technologies can reduce the need for physical samples, thereby lowering cost. In addition, the surrogate technologies can continue to estimate sediment concentrations when it is impossible or unsafe to collect physical samples.