Kongsberg Discovery manufactures a range of multibeam echosounders that produce high quality bottom backscatter data at all water depths. To produce the best quality bottom backscatter mosaics, it is recommended to conduct backscatter calibration for each sonar installation. This presentation will review current best practices for calibration, as well as recent developments and contributions by Kongsberg Discovery. These developments and contributions enhance the quality of backscatter data acquisition and calibration for the global hydrographic community.

Despite many years of work and technological advances to address the issue, refraction correction for multibeam echosounder surveys continues to be a vexing challenge, particularly in shallow and stratified near-coastal waters. Inadequately sampled sound speed profiles in both the spatial and temporal domains may lead to exceeding a project error budget, particularly for critical underkeel clearance or engineering surveys. Underway profiling systems allow survey crews to take more frequent casts, but at the cost of increased time and complexity required for data processing. We present an easy-to-implement sound speed cast acquisition intervention based on astronomical calculations for use in surface-mounted multibeam echosounder surveys in stratified waters with depths <100 m. This intervention assists survey crews on vessels equipped with underway profiling systems to optimize cast frequency while constraining errors related to sound speed. It also minimizes the processing and data management burdens associated with very frequent sound speed casts. We will examine results of similar surveys with and without the intervention, showing the improvement in data quality and the impact on the data processing burden in the intervention dataset. Finally, we will discuss how variations in local environmental conditions (particularly areas of freshwater intrusion) affect the success of the intervention.

Fugro has been a key player in geophysical site surveys supporting offshore wind development projects across the globe for many years. Offshore wind projects are characterized by strict client requirements towards bathymetry data quality, which often require mitigation of refraction issues and vertical mismatches between overlapping adjacent survey lines or blocks. This results in a significant amount of processing to meet these demanding client expectations. Given the typical short delivery timelines associated with offshore wind contracts in combination with a fast growth in project survey areas, it’s essential to ensure enhanced processing efficiency. Over the past years Fugro has put substantial effort into improving workflows related to the high expectations for data quality, as well as mining for efficiency in all stages of the processing workflow. To help achieve these goals Fugro has always worked closely with the team developing CARIS software at Teledyne Geospatial, and more recently that collaboration has been motivated by the demanding needs of offshore wind development. The collaboration has led to the deployment and improvement of existing tools in HIPS and SIPS as well as development of new tools to help improve overall quality of final products and the time taken to produce them. To name two specific examples, Fugro has gained significant efficiency by automating various workflow elements utilizing CARISBatch in combination with custom designed Process Models. Fugro also analyzed the Caris Process.log to reveal the overall majority of workstation processing time was dedicated to the core process ‘Georeference’. This discovery in part led to recent improvements in HIPS and SIPS version 12 which saw an overall reduction of workstation processing time of 18% to 46% (depending on workstation hardware). This presentation will highlight several examples of enhancements which were born out of collaboration and have helped Fugro incrementally improve quality and turnaround time for the final products, bringing value to both groups while ultimately benefitting the wider Hydrospatial community.

The demand for high-resolution multibeam surveys continues as part of numerous activities to support the Blue Economy, including mapping for safety of navigation, infrastructure, fishery habitats, renewable energy development and many more. While prominent shipping routes are often surveyed extensively, access to hydrospatial data in other areas is far less common. This is especially true for the Canadian Arctic where an extensive coastline, expansive marine environment, and remote geographic locations create logistically and environmentally challenging barriers to conduct surveys. With minimal data available and demanding conditions for new surveys, an accuracy assessment to quantify uncertainty becomes especially important. Short field seasons, harsh weather conditions, lengthy travel, minimal resources and other challenges often compound to restrict productivity in these remote locations. The goal becomes minimizing mobilisation times to maximize productivity during operational windows. Follow up visits to the project site are often not feasible, resulting in total data loss or unquantified uncertainty errors if issues with the survey setup are left undetected. The use of portable multibeam echosounders with tightly integrated positioning and motion sensors can dramatically reduce the time and cost associated with mobilising to a remote location. Offsets are known in advance and eliminate the need for vessel alignment surveys. It is however still possible for human or other errors to be introduced and result in erroneous data with optimistic uncertainties. With limited resources and insufficient test beds or comparison data other methods are needed to objectively verify results. The use of a ‘beam angle’ test in conjunction with the ‘plate check’ method offers a highly portable three-dimensional accuracy assessment that will help to truly quantify bathymetric uncertainty; even in remote areas.

Topobathymetric LiDAR has long been a technology available exclusively on fixed wing manned aircraft making it costly and inefficient for smaller targeted surveys. With the entrant of systems like the Riegl VQ 840GL, organizations can utilize unmanned aerial systems (UAS) to offer a service that provides more timely, efficient, and affordable topobathymetric LiDAR. Other benefit of UAS topobathymetric surveys include 200 points of elevation are provided per square meter offering unprecedented resolution that captures microtopology, scours, sediment impoundment and other geomorphologic characteristics. Whiteout Solutions is one of the first commercial vendors leveraging these technological advancements working with engineering firms, scientists, governments, and conservation groups to survey ecosystems experiencing the first order impacts of climate change. The rural community of Lyndonville, Vermont has a large floodplain that runs through its town center and has been subject to substantial flooding in recent decades. In late 2023, Whiteout Solutions survey roughly six miles of the Passumpsic river including two branches. Engineering firm, SLR International will leverage the high resolution topobathymetry data to develop models based on different flood mitigation solutions. The results of this work will provide the community with a series of options for how to improve the flood capacity and reduce the impact on the community. The high-resolution data not only is providing the engineering firm with more confidence in their models but also results in a Lyndonville becoming more resilient to the inevitable increase in flooding that will occur in the future. Whiteout Solutions has begun applying this new technology to diverse ecosystems, including coastal marshlands for erosion mapping and bird habitat research and river corridors for dam removal monitoring. New applications for the technology are arising every day, from article reef monitoring to oil slick dissipation research, all of which can add more insights into our ever-changing world.