Blue Gem Wind, the joint venture between Simply Blue Energy and Total is developing floating offshore wind sites in Welsh Waters of the Celtic Sea, Ireland. The first demonstration site is the 96MW Erebus Project approximately 44 km southwest of the Pembrokeshire coastline.ABPmer is part of the marine EIA team being led by MarineSpace, and has been commissioned to complete the physical process impact assessment in support of the Development Consent Order Application. The assessment will investigate the potential effects of the WindFloat floating wind platform and supporting infrastructure on the wave, flow and sediment transport regime through construction, operation and decommissioning of the wind farm. New physical process impact assessment methods will be developed to account for the different underwater profile and mooring systems used by the WindFloat platform. Existing methods and evidence will be used to inform the assessment of potential impacts from the more traditional transmission infrastructure.