Pinpointing the best location for tidal energy turbines and providing a picture of seafloor conditions underneath fish pens are two research projects benefiting from the autonomous underwater technologies expertise at the Australian Maritime College.
The projects were funded by the University of Tasmania’s research enhancement scheme, designed to help early to mid-career academics increase their competitiveness for external research funding.
For the first project, Dr Alex Forrest deployed the autonomous underwater vehicle (AUV) UBC-Gavia to map the seafloor underneath the Batman Bridge in Launceston’s Tamar River and at Swan Island near Musselroe Bay, North-East Tasmania. These two sites have been identified as key areas for potential tidal energy recovery.
“Underwater turbines need to be aligned with the tidal flow to maximise the return of energy, so if you have a detailed picture of what the site looks like you can maximise the efficiency of your turbine,” Dr Forrest said.
The two deployments have been deemed successful with the data retrieved clearly showing the areas of highest potential tidal turbines within the surveyed areas. Dr Forrest plans to write a paper summarising these findings for publication in ocean engineering and renewable energies journals.
The second project led by Dr Vanessa Lucieer from the Institute for Marine and Antarctic Studies focused on mapping the bathymetry of the seafloor around aquaculture facilities. Traditional surveying techniques are only capable of mapping the seafloor surrounding the fish pens, so when you look at the map there are holes where the fish pens are located.
Dr Lucieer has surveyed many sites in the D’Entrecasteaux Channel, South-East Tasmania for the environmental assessments prior to the development of aquaculture facilities in the past 10 years. Usually the mapping methodology involves sounding the seafloor with single beam acoustics from a vessel which produces maps at 50-metre resolution.
The UBC-Gavia allows the seafloor to be “swath mapped” so the resolution of seafloor features can be refined to 20-centimetres in resolution. “The benefits of using the AUV include increased surveying time, finer resolution bathymetry and freeing up the deployment vessel to go and collect sediment cores and video to validate the acoustic data,” Dr Lucieer said.
“This can be done simultaneously while the AUV is collecting acoustic data, which leads to a much more efficient survey. The fine scale bathymetric data that is collected is also of much higher quality, resolution and value for seafloor current flow modelling in and around the aquaculture facility, which is of great value to the industry.”