Multilevel Environmental Impact Analysis - Environmental Impact Analysis: Process and Methods - page 230

consumption and climate change, each subsequent environmental analysis
on specific actions to implement the policy addresses only the impacts of the
specific action (e.g., a wind turbine, regional geothermal heat, fuel efficient
mass transit) and does not have to repeat the analysis of multiple fuel use
policies.
In a tiered or programmatic EIS, the objective is to evaluate alternatives and
address issues that are “ripe for decision,” but the challenge is to determine
when issues are in fact truly ripe. Having enough information to fully evalu-
ate the environmental impacts that would result from alternative courses
of action is a primary criterion in determining the ripeness of an issue for
decision. A frequent conclusion is that there is enough information to com-
pare multiple general courses of action, but there is not enough information
to evaluate the implications of implementing specific actions. In such cases,
implementation details can be deferred to subsequent NEPA review by a
tiered EIS, supplemental EIS, EA, or equivalent NEPA process.
Another criterion in determining ripeness for decisions is potential con-
straints imposed by a premature decision that limits the available options
for subsequent components of the action. The prematurity of the decision
with respect to constraining other aspects of the purpose and need can be
evaluated by first identifying a range of implementing alternatives for each
component of the action and describing them in general terms. If it can be
clearly demonstrated in the initial or programmatic EIS that decisions made
will not constrain the range of alternatives for other aspects of the program,
the decision may be ripe in this respect in the initial or programmatic EIS.
However, if a number of implementing alternatives are shown to constrain
follow-up decisions, then it may be necessary to defer the decision to the next
tier of the NEPA process.
An example of a programmatic EIS limiting the options in subsequent tiers
is illustrated by a hypothetical example for a sustainable electrical power pro-
gram for a region. The purpose and need of this hypothetical programmatic
EIS is to develop multiple sources of energy to provide future flexibility if
conditions change, such as restricted availability of fuel for power produc-
tion. One of the alternatives relies on a mix of hydropower, developed on
the region's major river, and nuclear power generation. In this hypothetical
example, this alternative is selected and the Record of Decision (ROD) calls
for tiered EISs for the development of each separate source of electrical power.
During parallel preparation of the tiered EISs for nuclear and hydro-
power following the hypothetical regional energy programmatic EIS, a
major conflict was uncovered. Because of substantial water needs for cool-
ing the nuclear power plant, the only available source was the major river
in the region. The other tiered EISs for hydropower was found to limit the
availability of water during dry conditions, and there was no guaranteed
source of cooling water for the only acceptable nuclear power plant site. In
this hypothetical example, the entire program would have been required to
go back to a supplemental programmatic EIS and reconsider the selected