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105. Contin uous Measurement of Suspended-Sediment Discharge in Rivers by Use of Optical Back scatterance Sensors

2004; Elsevier BV; Volume: 14; Issue: 2 Linguagem: Inglês

1878-4364

David H. Schoellhamer, Scott A. Wright,

Fish Ecology and Management Studies

Optical sensors have been used to measure turbidity and suspended- sediment concentration by many marine and estuarine studies, and optical sensors can provide automated, continuous time series of suspended-sediment concentration and discharge in rivers. Three potential problems with using optical sensors are biological fouling, particle-size variability, and particle- reflectivity variability. Despite varying particle size, output from an optical backscatterance sensor in the Sacramento River at Freeport, California, was calibrated successfully to discharge-weighted, cross-sectionally averaged sus- pended-sediment concentration, which was measured with the equal dis- charge-, or width-increment, methods and an isokinetic sampler. A correction for sensor drift was applied to the 3-year time series. However, the calibration of an optical backscatterance sensor used in the Colorado River at Cisco, Utah, USA, was affected by particle-size variability. The adjusted time series at Freeport was used to calculate hourly suspended-sediment discharge that compared well with daily values from a sediment station at Freeport. The appropriateness of using optical sensors in rivers should be evaluated on a site-specific basis and measurement objectives, potential particle size effects, and potential fouling should be considered.