CV21035 Celtic Voyager 2021 Mobility of Sediment Waves and Sand Banks in the Irish Sea Phase 2 (MOVE 2) Leg 1

With the sudden increase in offshore infrastructure developments in the Irish Sea, expert knowledge of seabed morphodynamics and sediment mobility is of huge importance. Significant vagrancies exist regarding seabed morphodynamics and the potential for sediment mobility in the Irish Sea. The technical challenge of gathering data surrounding morphodynamic and hydrodynamic associated processes in this environment is a trying one. Data that can be gathered include traditional seabed mapping techniques, such as multi-beam echosounder (MBES) to image the seabed and sub-bottom profiling (SBP) to visualise seabed structure below the surface. Both these methods offer an image of the seabed and sub-seabed at a given point in time at its collection but have limited value in fully understanding a mobile sediment environment. Scientifically, the challenge is to utilise this data robustly to develop an understanding of how the seabed has developed temporally and spatially. By conducting high precision, high-resolution repeat surveys, time-lapse imagery of the seafloor can be generated. Repeat surveys reveal differences in seafloor bathymetry, accretion and rate of bedform migration. MOVE 2 Leg 1 CV21035 is a University College Cork (UCC) and SFI Research Centre for Energy, Climate and Marine (MaREI)-led project in collaboration with Gavin and Doherty Geosolutions (GDG), University College Dublin (UCD) and SFI Research Centre for Applied Geosciences (iCRAG). MBES and SBP data were collected at 11 sites over 15 hours of work (reduced working time due to unworkable weather conditions) in the south-western Irish Sea. ADCP deployment, water sampling and sediment sampling that couldn’t be carried out over MOVE 2 Leg 1 will be carried out in Leg 2. This work builds upon the high-quality geophysical and metocean datasets that were collected by MOVE 1 (CV20010 and CV20035) and INFOMAR surveys in south Irish Sea. In general, the MOVE project fosters a firm collaboration between strongly technical researchers actively addressing some of the key challenges facing Ireland in terms of managing seabed resources and developing offshore renewable energy sources to help us meet our climate change targets. It addresses some of the key priorities set out in Harnessing Our Ocean Wealth Roadmap which aims to build a thriving maritime economy that harnesses economic growth whilst also being cognisant of healthy ecosystems and sustainably managing our activities at sea. The MOVE project does so by providing key baseline data and research for both and promotes future collaboration between academia and industry to help achieve these goals. Specifically, the project supports the Ocean Renewable Energy Development Plan (OREDP) in technically assessing key areas for renewable energy installation development and critically de-risking them. The scientific goal of the MOVE 2 survey can be broken down into five objectives: 1. To build upon MOVE survey phase 1 (CV20010 and CV20035) by gathering critical high resolution interannual geological and geophysical datasets to investigate the nature of sediment mobility and morphodynamic changes in selected sites of the Irish Sea known for highly complex hydrodynamics; 2. To examine the physical processes occurring on the seafloor with respect to seabed morphodynamics pertinent to engineering projects; 3. To provide data to validate 2D hydrodynamic, sediment transport and morphological numerical models that will form the basis of understanding the complex morphodynamics and its underlying drivers in the south Irish Sea; 4. To gather critical site-specific environmental data to feed in to modelling efforts to help predict future changes in seabed morphology in reaction to anthropogenic impacts and climate change; 5. To build up a unique Geographical Information System (GIS) based database of offshore seabed morphology and sediments in the Irish Sea that can be used in future engineering and environmental studies. The MOVE 2 Leg 1 survey fundamentally assists the better understanding of seabed sediment dynamics in the Irish Sea. This has direct implications for several sectors, including: · The construction of offshore renewable energy by identifying areas where it is feasible to profitably build foundations and site cable routes ashore; · The improving of habitat maps to inform environmental assessments and fisheries research by integrating additional site condition information; · The developing of critical baseline information and models with which to assess climate change effects including coastal erosion.