Recorded data with EM2040 MBES, EK80 SBES and Aquascat system during the BSinFlume feasibility experiment in the Delta Flume, Deltares, Netherlands in 2020.

Multifrequency single- and multibeam echosounders are mature technologies for underwater mapping. However, the current scarcity of sediment reference datasets of both bottom backscatter angular response and water column scattering, hampers the generation of applicable information. Reference data derived from measurements in a controlled environment should optimize the use of empirical backscatter data for underwater observation and management. In order to prepare for such comprehensive and ground-breaking experiments, we conducted a feasibility experiment in the Delta Flume, Deltares, Netherlands. Multi-frequency single- and multibeam echosounder data of the flume floor and of fine-grained, in-water sand plumes were recorded. The results revealed that flume reverberation did not interfere significantly with bottom targets and that fine-sand plumes in the water column were clearly detected. Future comprehensive experiments will feature multi-frequency multi-angle measurements on a variety of sediment types, shell densities, interface roughnessess, and plumes of various sediment grain sizes, shapes and concentrations.