ation and the planning process, usually necessitate is a study-specific adaptation of the tiering concept 



performing and repeating phases and activities in described in the CEQ NEPA regulations (40 CFR 



increasing levels of detail, each level commensu- 1502.20 and 1508.28). The level of detail and 



rate with the evaluation needs of the overall plan- number of stages will vary with each planning 



ning effort. Such repetitions are called stages in study, but the following stages, shown graphically in 



these procedures. Conducting EQ evaluation in Figure 3.4.1-2, should be considered for every 



stages of increasing levels of specificity and detail study. 



108 



