Multilevel Environmental Impact Analysis - Environmental Impact Analysis: Process and Methods - page 251

were not implemented, and the option of moving forward on this basis was
rejected.
Another option was to address impacts on the natural environment by
“inclusion by reference” to the 2008 EIS and embark on preparation of an EA
to analyze the economic impacts. Preparation of the EA would begin by
addressing the scarcity of economic data as cited in the first environmental
impact analysis and initiating an investigation of shipping economic data
to fill the gaps of the 2008 analysis. However, there was the real possibility
that an economic evaluation using the new data could indicate a significant
impact to the economic viability of the shipping industry for one or more of
the DCR management alternatives. This could then require a full EIS if an
alternative with significant economic impacts was selected, resulting in lost
time and expenditure of resources. Thus, this alternative was also rejected.
Another alternative was to conduct a supplemental EIS that included the
new economic data and results of the new alternative/mitigation measures'
effectiveness evaluations to reevaluate the alternatives in light of the new
data. This alternative was very attractive in that it could proceed expedi-
tiously and would be very efficient because most of the information had
already been fully vetted by the public. The supplemental EIS would simply
describe the extensive effort to evaluate the cost and effectiveness of alterna-
tive DCR discharge control methods and then analyze the economic impact
to the shipping industry resulting from the implementation of the measures.
These costs could then be weighed against the benefits to the natural envi-
ronment as described in the 2008 EIS, to make a decision regarding DCR
management regulations with a full understanding of environmental impli-
cations as dictated by NEPA.
Another equally attractive option was to conduct a tiered EIS, accepting the
conclusions of the 2008 EIS with regard to impacts on the natural environ-
ment and continuing the alternative/mitigation measures' effectiveness and
economic evaluation initiated in the first EIS. This had the same advantages
as the supplemental EIS because it minimized duplication, was efficient, and
made full use of the information and conclusions already presented to the
public. A tiered EIS also had the advantage of using compliance with the
interim rule as the existing condition, whereas there was some question as
to whether a supplemental EIS would be required to have the same starting
point as the original EIS to represent existing conditions. The choice between
a supplemental EIS and a tiered EIS was difficult, but in practice it made
little difference. Both took full advantage of the work that was already done
and could be executed efficiently. Both options also provided an efficient and
accepted approach to incorporating new information and using the informa-
tion to evaluate and select a course of action for promulgating DCR man-
agement regulations. In the final analysis, the USCG decided to conduct a
tiered EIS, although a supplemental EIS could also have accomplished the
objective. The tiered EIS represented an approach of moving forward from a
decision already made when the time was “ripe” and subsequent decisions