The patented sensor measures a vertical turbidity profile through the water / sediment interface, and estimates the level of the bottom with sub-millimeter resolution. The current generation, SM4, features nephelometric turbidimeters (calibrated in NTU and FNU), fluorescence meters, accelerometer, conditions-based monitoring, and UV anti-fouling. We are also adding an OBS backscatter turbidimeter (calibrated in FBU) to new SM4 units, for situations with over 400 FTU turbidity. (The SediMeter™ on the photo is model SM3A, which was our best selling model during a number of years.)
The half dome in the photo above is a radio modem with integrated solar panel. Various types of radios can be used in it, to create a wireless telemetry system.
To convert the turbidity data to suspended sediment concentration (SSC) one must take a sample of the latter. The Nilsson sampler is a light-weight (11 kg) sampler that nonetheless is useful in up to 200 cm/s stream velocity.