High Precision and Range of Concentration Measurement for Sediment-Water Mixture based on Time Domain Reflectometry

Concentration measurement of sediment-laden flow is crucial in studying river morphology, impact of climate change on sediment yield from watershed, reservoir sedimentation management, and ecological impact. Suspended sediment concentration (SSC) in above applications ranges from sub 1g/L (1000 ppm) in natural streams to over 500 g/L (500,000 ppm) in dredging production. Particle size dependency is also an issue on top of the challenge to meet such a wide measurement range for any measurement technique. Dielectric-based method is recently developed to overcome these challenges using time domain reflectometry (TDR) technique. This study aimed to enhance the measurement precision and range through an advanced signal processing technique and a rigorous frequency-dependent dielectric mixing model. Probe and material factors were investigated to rationalize the necessary calibration. Experiments on both the lower SSC range and high SSC range verify the excellent performance of TDR method for SSC measurements.