Industry News

Sequoia Scientific, Ocean Instruments and Geometius Deliver Sediment Dredging Measurement System

Ocean Instruments (Fall City, WA), and Sequoia’s Dutch distributor, Geometius, have delivered a Fast Oceanographic Automated Measurement (FOAM) system for dredge monitoring.

The FOAM system is composed of a pump and winch with a fluid rotary joint, 100 m hybrid cable with hose and conductors, a tow sled with an RBR CTD and a Sequoia LISST-ABS, and a topside mounted Sequoia LISST-200X running in flow-through mode.

The sled is towed through the dredge plume, while water is continuously pumped through the hybrid cable and winch to the topside LISST-200X. This unique setup delivers particle size, concentration (from laser as well as acoustic backscatter), and other pertinent parameters from the CTD in real-time as the sled is being towed and yo-yo’ed through the dredge plume from a vessel of opportunity.  In addition to real-time measurements, this specialized system allows for co-located water samples to be collected on deck for ground-truthing sensor data.

The FOAM system itself was initially designed by Ocean Instruments for un-biased water sample collection and in-line measurements on an underway vessel. A number of systems have been delivered for moving vessel particle sampling. To name a few: Chlorophyll sampling for harmful algal blooms in the Puget Sound, suspended sediment monitoring in the Caspian Sea, and oil spill response studies in Mexico.

For the present system, Sequoia’s LISST-200X and LISST-ABS was integrated into the system and tested prior to delivery. The complete system: instrumentation, winch, hybrid cable and tow sled, together with spares, was delivered by Sequoia to Geometius. Installation, commissioning and training was originally planned on-site in Europe. However, due to the COVID-19 outbreak it was performed virtually by Ocean Instruments and Sequoia via a series of rapidly produced training videos and online training sessions.

For more information, click here.

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