Sequoia Scientific, Inc. has developed the first advanced technology laser diffraction system for measuring sediment properties in rivers and streams. The streamlined body is a minimum drag shape. Twin fins below the body orient the LISST-SL facing upstream before insertion. A propeller on top of the body measures river velocity. The system employs active control of the intake pump that matches river velocity to intake velocity making the sample acquisition isokinetic. Diffracted light is measured in an enclosed electro-optics test section. Data are transmitted up the USGS B-reel to a 'topside' Control Box. The detailed size distribution and volume concentration is recovered after data processing. Depth, velocity, and temperature are stored with each sample. With the included depth data, the system is capable of delivering sediment flux in the river.
