A GIS predictive model is being created to highlight potential archaeological sites along drowned paleoshorelines using bathymetric data combined with notions in past settlement patterns and detailed sea-level curves. The study area is along the coast of the Pacific Northwest and has seen a significant net sea level rise since the last ice age at the end of the Pleistocene. Such models are increasingly used tools to further narrow down search areas of terrestrial and underwater cultural sites alike and have demonstrated their value. Finding underwater archaeological sites has the potential to change our understanding of the people’s migration to the Americas. The GIS predictive model created during this study uses proxies of site suitability and site survivorship that are represented by three parameters derived from elevation data: wind fetch, coastal complexity, and slope. Each parameter is computed along multiple paleoshorelines, from the lowest estimated sea levels up to present-day chart datum. A weighted overlay method is applied to determine the most plausible locations for cultural material accumulation due to past human occupation, and for cultural material to have survived thousands of years underwater. Limitations of the predictive model are discussed, and a seabed characterization is done alongside to compare and evaluate results. Research permission was requested to the Indigenous nation on who’s territory the study area lies. Permission was granted with certain conditions of oversight. As such, the results are to be shared only with the nation’s cultural resource management branch at this time. Due to the potential sensitivity of the information contained in the resulting maps, publications, reports or displays must first be approved by the nation.

Contexte : Océan s’est fait octroyer, en 2023, un contrat comprenant entre autres, la bathymétrie, le dragage et la disposition terrestre d’une quantité d’environ 120,000m³ de sable destiné à être utilisé pour de la protection côtière aux Iles-de-la -Madeleine, dans le golfe St-Laurent. Ces travaux maritimes et de disposition des sédiments se sont réalisés entre le début juillet et la fin septembre 2023. Objectifs : Démontrer l’importance de l’hydrographie et de la géomatique dans le domaine de la protection côtière. Encourager la recherche vers des produits innovateurs dans la classification des fonds marins afin d’identifier rapidement et efficacement les bancs d’emprunts pouvant servir à la recharge de plage à l’aide d’une drague. Méthodes : Le dragage des sédiments, utilisés dans le projet de protection côtière, a été réalisé à l’aide de la drague Océan Traverse Nord qui est une drague à succion à élinde trainante munie des plus récentes technologies en dragage de précision. La localisation des bancs de sable ainsi que le contrôle des volumes se sont faites par levés bathymétriques à l’aide d’un échosondeur multifaisceaux R2Sonic 2022. Résultats – Discussions : La présentation portera sur l’importance du suivi bathymétrique sur un projet de protection côtière comme celui effectué en 2023 aux Iles-de-la-Madeleine. Une explication sur la méthode de dragage et de disposition terrestre sera faite également. Conclusion : Le projet sera revu dans son ensemble avec un bref aperçu des livrables au client (Ministère des Transports et de la mobilité durable Québec). Des recommandations seront présentées concernant l’apport que pourrait amener les outils hydrographiques pour la mise en place et le suivi de l’évolution sur les projets de protection côtière.

In 2021, Kraken Robotics (formerly PanGeo Subsea) was contracted to conduct a Sub-Bottom Imager (SBI) survey to support a harbour deepening campaign on the East coast of the United Kingdom. The SBI was mounted on an EIVA platform called the SeaKite which is a remotely operated towed vehicle (ROTV). To perform the dredging safely and effectively in the harbour, all subsea boulders and other buried obstructions must be identified to minimise the risk of impeding the operation or damaging the dredging equipment. The SBI data was acquired to support the bathymetry data within the channel approach and inner harbour areas where water depths were recorded less than 16 m. Since the channel deepening campaign dredged up to 2 m below the seabed, the bathymetry data alone is insufficient to identify boulders that lie below the seabed, which introduces a danger of potentially excluding a significant number of obstructions. Data interpretations were performed using EIVA Navimodel and were performed in four sections based on a priority system, and approximately 36,600 discrete anomalies were interpreted. Using a GIS workflow, a boulder density map was generated to divide the survey into blocks, 11 blocks of dense boulder accumulation, >100 boulders per ha at 3 m depth of burial (30,000 m³), were analysed.

Shipboard multibeam echosounders often provide a smoothed representation of rough deep-water topography that cannot adequately characterize the vertical dimension of complex 3D seafloor structures of ecologically important habitats such as cold-water corals. These steep environments harbor rich and diverse filter-feeding communities and provide a natural protection for vulnerable species against trawling activities, but require specialised tools for ultra-high resolution mapping. In September 2023, a Schmidt Ocean Institute-funded expedition onboard the research vessel Falkor(too) focused on the exploration of vertical cold-water coral (CWC) cliff ecosystems in the Galápagos Archipelago using a Voyis MicroInsight laser scanner and a Norbit WMBS multibeam echosounder front-mounted on a work-class remotely operated vehicle. The primary objectives were to create high-resolution maps to precisely identify and delineate biological underwater features, and explore the potential of combining ultra-high resolution laser-scanning and traditional hydrographic survey methods such as MBES. The mounting bracket holding both systems on the ROV porch was designed to enable variable angles in 15° increment and was set prior to the dive. This equipment was employed to map three sections of coral reefs discovered at ~350m in depth. A range of exposure times were tested, and acquisition and georeferencing took place in Voyis’ ViewLS software. We acquired 2.9 Terabytes of data, with estimated point cloud density varying between 192,500 – 220,000 points per square meter. Datasets were imported in EIVA NaviSuite to undertake patch test calibration and post processing, while 3D point clouds are being visualized in ArcGIS Pro and Cloud Compare software packages. Preliminary observations indicate that different biological taxa showed differences in reflexivity, with sponges showing higher intensity. This work will allow us to measure habitat complexity and start assessing the reliability of this approach to monitor habitat quality overtime.

The development of increasingly high-performance seabed mapping systems has become a major challenge to meet new needs: in maritime safety for infrastructure inspection, particularly offshore wind turbines and cable route; to identify and delimit marine protected areas and assess the environmental impact of deep-sea mining; to improve our global knowledge of the oceans and marine life. This paper will present the last development on the Synthetic Aperture Mapping Sonar (SAMS150) at Exail . This interferometric sidescan sonar has been designed to optimize the compromise in between area coverage rate and resolution performances on AUV as well as on tow fish. The system offers all the possible imaging modes from conventional single beam interferometry sidescan to multibeam interferometry sidescan processing and synthetic aperture processing with constant gain or constant resolution option. QA/QC criteria may be computed and displayed as overlapped layer on the mosaic and bathymetry map giving a global and precise view of the quality of the imaging systems. We will give some particular attention to the development of calibration procedures and results obtained at sea.