Evaluation of aDcps for suspended sediment transport monitoring, Fraser River, British Columbia

Our ability to predict the timing and quantity of suspended sediment transport is limited because fine sand, silt and clay delivery are supply-limited, requiring empirical modelling approaches of limited temporal stability. Here, I evaluate a 300 kHz side-looking acoustic Doppler current profiler (aDcp), mounted in the Fraser River, BC, for continuous measurement of suspended sediment flux. I also evaluate a downward-looking 600 kHz aDcp at the same site. Both aDcps are calibrated against conventional bottle samples obtained with a USGS P63 sediment sampler. The results suggest that it is possible to estimate total suspended sediment flux using a 300 kHz side-looking aDcp in the Fraser River, but that it underestimates observed flux. The calibration of the 600 kHz aDcp is strong (R2=0.72), but it underestimates total sediment flux at low-moderate flows and overestimates flux at high flows.