A Self-Contained Sector-Scanning Sonar for Bottom Roughness Observations as Part of Sediment Transport Studies

Abstract

Abstract Studies and models of sediment transport in the bottom boundary layer require knowledge of the bottom roughness as a parameter affecting the suspension and transport of sediment. Knowledge of this has often been quite imprecise since measurements could only be made from diver observations or camera pictures at times when the water was clear. A self-contained, tripod-mounted rotating-beam sonar system has been developed, which allows bottom topography to be imaged on scales of a few square centimeters out to 4-m radius at regular intervals in time. Most importantly, this system produces images during high suspended sediment concentration transport events, when knowledge of the bottom structure and movement is most crucial. To accomplish this, a Simrad/Mesotech sonar head was adapted as the sensing element for remote use. A separate self-contained controller/recorder was constructed and housed in its own pressure case with sufficient battery and storage capacity for up to six months deployment with...