chapter  26
20 Pages

Planning in Tiers? Tiering as a Way of Linking Sea and Eia

The idea of tiering can be considered as one of the major drivers for the

development of strategic environmental assessment (SEA) (see, for example,

The

´

rivel et al, 1992; UNECE, 1992; Wood and Djeddour, 1992; The

´

rivel and

Partida

´

rio, 1996; Sadler and Verheem, 1996; Partida

´

rio, 1999; Fischer, 2002a;

Wood, 2003). Many decisions that have a bearing on environmental quality are

taken at a higher level of decision-making than the project level. As Partida

´

rio

(1999, p60) indicates: ‘The reasons [for SEA] are various but initially related to

the timing of project [environmental impact assessment] EIA, i.e. it enters the

decision-making process at too late a stage to be able the final decision in a

satisfactory way.’ Tiering means that, by preparing a sequence of environmental

assessments (EAs) at different planning levels and linking them, foreclosure may

be prevented, postponement of detailed issues may be permitted and

assessments can be better scoped. A tiered approach minimizes the problem

of EIA being only a ‘snapshot in time’. Accordingly, the European SEADirective

(2001/42/EC) explicitly assumes tiering of SEAs and EIAs at different planning

levels and the SEA and EIA Directives are directly linked.