SEA and EIA: uncertain boundaries in Spain

ABSTRACT Environmental impact assessment (EIA) of projects and strategic environmental assessment (SEA) of policies, plans and programmes allow environmental aspects to be incorporated into decision-making. The literature and regulations sometimes present SEA and EIA as isolated silos, but in practice there are intermediate approaches. This paper discusses a number of case studies where the application of EIA and SEA is conceptually unclear, although legally appropriate. The application of SEA or EIA depends in practice on the name of the planning document used, rather than its strategic character, with non-strategic SEAs and strategic EIAs due to a mismatch between planning and EA. The gradual transition between SEA and EIA makes it advisable to establish similar administrative procedures, as well as a common screening stage to determine not only whether or not the proposal should be subject to EA, but also the most appropriate approach. More than one EA process may be necessary throughout the planning cycle, requiring effective tiering. The regulations should define what is considered strategic, and regulate the tiering between SEA and EIA processes.