Author(s): John R. Gray; Yogesh C. Agrawal; H. Charles Pottsmith
Linked Author(s):
Keywords: Suspended sediment; Sediment measurement; Sediment Surrogate; Sediment sampling
Abstract: The new manually deployed Laser In Situ Scattering Transmissometer-StreamL ined profiler (LISST-SL) represents a major technological advance for suspended-sediment measurements in rivers. The LISST-SL provides reliable real-time data on sediment concentrations and particle-size distributions. A pressure sensor and current meter provide real-time depth and ambient velocity data, respectively. The velocity data also are used to control pumpage across an internal laser so that the intake velocity is constantly adjusted to match the ambient stream velocity. Such isokinetic withdrawal is necessary for obtaining representative sedimentary measurements in streamflow, and ensures compliance with established practices. The velocity and sediment-concentration data are used to compute fluxes for up to32 particle-size classes at points, verticals, or in the entire stream cross section. All data are stored internally, as well as transmitted via a 2-wire conductor to the operator using a specially developed communication protocol. The LISST-SL’s performance will be measured and compared to published sedimentological accuracy criteria, and a performance summary will be placed on-line.
Year: 2004