Murawski, S.A., Gilbert, S., Hommeyer, M., Liu, Y., Lembke, C., Grasty, S., English, D., Hu, C., Dixon, T. 2025. Marine Technology Journal, 59:62-77. https://doi.org/10.4031/MTSJ.59.2.6

Abstract: Shallow waters (< 30 c.a. m deep) represent at once the most accessible region of the world’s oceans and coasts, but its most challenging in terms of efficient broad-scale, high-resolution mapping, hazard identification, and habitat characterization. Hazards to navigation are primarily a coastal threat and thus the requirement for high-resolution (< 1 m) maps are critical for well-traveled parts of the coastal ocean. Traditional sonar mapping approaches rely on acoustic swath widths that are proportionally wider with increasing water depths. High-resolution landscape-scale maps in shallow waters thus require numerous closely spaced transects that may be prohibitive in ship time and data processing costs. Alternatives to multibeam, single beam, and side scan sonar include satellite-derived bathymetry, airborne Light-Detection and Ranging, autonomous surface and underwater vehicles, and, increasingly, the use of crowd-sourced bathymetry to gather and disseminate depth sounder data from community participant vessels. Each of these approaches has its advantages (e.g., resolution, synopticity, calibration/validation, utility in turbid waters, efficiency for repeat measurements) and drawbacks (e.g., costs, platform availability and logistical considerations). Local requirements, challenges, conditions, and capacities will dictate which techniques or combinations render adequate resolution. As an alternative to a single technology solution, we advocate multisource coupling to blend information from multiple mapping approaches with the overall goal being a synthesized map explicitly depicting uncertainties in bathymetry due to differences in observational characteristics of technologies employed. Higher resolution technologies can be deployed where the accuracy of the map is commensurate with elevated threats/interests. Principles of multiplatform data acquisition, data processing, and display for shallow water bathymetry are illustrated using data collected during the Tampa Bay (USA) Bathymetry Experiment (TBBEx) conducted in 2021‐2022.

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