Authors: Picard, K., Austine, K., Bergersen, N., Cullen, R., Dando, N., Donohue, D., Edwards, S., Ingleton, T., Jordan, A., Lucieer, V., Parnum, I., Siwabessy, J., Spinoccia, M., Talbot-Smith, R., Waterson, C., Barrett, N., Beaman, R., Bergersen, D., Boyd, M., Brace, B., Brooke, B., Cantrill, O., Case, M., Dunne, S., Fellows, M., Harris, U., Ierodiaconou, D., Johnstone, E., Kennedy, P., Leplastrier, A., Lewis, A., Lytton, S., Mackay, K., McLennan, S., Mitchell, C., Nichol, S., Post, A., Price, A., Przeslawski, R., Pugsley, L., Quadros, N., Smith, J., Stewart, W., J., S., Tran, M., Whiteway, T.
Publication: Australian Multibeam Guidelines. Record 2018/19, Geoscience Australia, Canberra, Australia, pp. 69.
High-resolution seafloor mapping has developed into a significant area of marine surveying in the past few decades and has had an increasingly large number of drivers and applications:
• Navigation and safety of life at sea
• Environmental assets management (including Fisheries management)
• Ocean and climate modelling
• Hydrodynamic modelling
• Coastal and nearshore sediment mapping
• Resource development
• Aquaculture planning
• Oil and gas subsea assets integrity
• Telecommunication cable deployment
• Renewable energy assessments
• Marine spatial planning
• Territorial claims
• Demonstration of Antarctic presence
• Underwater cultural heritage management
• Artificial reef development
These applications have resulted in seafloor mapping in locations from the upper reaches of estuaries to the abyssal plain.
In Australia, much of the focus has been on continental shelf and slope waters at varying levels of coverage and resolution reflecting the drivers for mapping, vessel and gear availability, and the combination of targeted and opportunistic data collection. However, despite a significant increase in survey coverage in the past decade, less than 25% of the seafloor in Australia’s maritime jurisdiction is mapped at high-resolution.
Since only the narrow coastal margin of the seafloor can be seen from aerial or satellite images, or mapped using laser airborne systems, swath acoustic mapping systems, principally multibeam echosounders (MBES) and bathymetric sidescan (interferometric sonar), have been the systems most used to map Australia’s seafloor. These swath systems collect several specific measurements: water depth, seabed backscatter (commonly known as seabed hardness), and in some cases with MBES, water column backscatter. While MBES data is acquired by many groups to meet specific purposes, with increasing coverage and specific mapping programs in government agencies, research institutions and industry, it is important to ensure swath mapping data is made available to use for a range of applications (Table 1).
The primary objective of this guideline is thus to establish common approaches of acquisition and processing that will result in greater applicability and interoperability of swath acoustic mapping data. These approaches will also provide improved consistency in the collection and description of the data, increasing utility.