Research 391: Tiering of Environmental Assessment – The Influence of Strategic Environmental Assessment on Project-level Environmental Impact Assessment

Strategic Environmental Assessment (SEA) and Environmental Impact Assessment (EIA) aim to identify and mitigate environmental impacts resulting from plan, programme (the realm of SEAs) and project (EIA) implementation. The organised transfer of information and issues from one planning and assessment level to the other (e.g. SEA to EIA) is known as tiering. This report examines tiering of environmental assessments, focusing on the influence of SEA on EIA, with regard to both processes and outcomes. This examination has been informed by a review of relevant international literature, 21 Irish SEA and EIA case studies and 28 interviews with international and national SEA and/or EIA expert