Continuous measurement of suspended sediment concentration: Technological advancement and future outlook

• Status of CMTs for suspended sediment concentration (SSC) measurement presented.
• Turbidity CMT is most commonly used. Acoustic CMT can measure in a cross section.
• Laser based CMT provides particle size distribution along with SSC information.
• Digital image and spectral reflectance CMTs have high potential to measure SSC.

Sediment affected water resources require frequent and accurate suspended sediment concentration (SSC) data for proper design, operation and management. The traditional method of collecting water samples is inadequate to provide such large amount of SSC data. Recently, the principles based on optics, acoustics, density, electric properties have shown promising results in the direction of providing continuous SSC data. Namely a few technologies, as some are based on turbidity, laser diffraction, acoustic backscatter, are widely applied in field conditions, whereas others are employed under the development phase. The present article focuses on the recent developments of these technologies along with their basic working principle, advantages, limitations, and field applications. Calibration, as an important aspect for these technologies, is also discussed in detail. The review provides a valuable insight for the researchers and professionals by adding fundamental understanding for selecting the most appropriate measurement technology to monitor SSC efficiently and continuously.