Australia’s federal Government has identified six offshore renewable energy zones, with a region of Bass Strait off the Gippsland coast in eastern Victoria being the first area declared. The dynamic nature of local shorelines, and the sensitivity of coastal sediment transport processes to small, systemic changes in metocean climate, presents a need to establish the downstream impact pathways introduced by a large offshore wind array and evaluate the significance of effects at the coastline.
Evaluation of a project’s marine and coastal impacts requires understanding of physical environment dynamics over the lifetime of the development and quantification of how wind turbine generator (WTG) arrays may alter ocean patterns downstream. Physical obstructions exert direct influence at small scales on passage of waves and currents, while indirect influence on wave growth downwind of the development is exerted at large scales via cumulative wake deficits. Impact pathways must be examined via suitably calibrated hydrodynamic and wave models, with appropriate parameterisation of transmission and reflection coefficients, and customisation of wind shadow effects in model forcing fields. Characterisation of winds, waves and currents in the nearshore zone will allow evaluation of potential downstream changes from pre- to post-development states and provide critical input to landform assessments.