Conducting the Environmental Impact Analysis and Assessment - Environmental Impact Analysis: Process and Methods - page 190

impact analysis; thus all of the other steps described in this and previous
chapters are conducted to support the prediction of impacts. Successful com-
pletion of all the other steps (e.g., scoping, description of affected environ-
ment, development of alternatives, and impact conceptual model) frequently
results in an impact prediction process that is simple, straightforward, and
virtually automatic. Take for example the OTH radar in northern California
(Section 5.2.5) where a thorough description of the affected environment with
respect to large mammal migration and cultural resources supported devel-
opment of a proposed action with no impact on these resources. Similarly,
the understanding of the existing conditions and causes of eutrophication
in the Scituate, Massachusetts, nearshore environment (Section 5.2.4) made
it very clear that locating a wastewater effluent outfall close to shore would
exacerbate an already marginal water quality and estuarine ecosystem con-
dition, and locating the outfall beyond that point would improve conditions.
Thus in the planning phase of the environmental impact analysis, the even-
tual prediction of impacts should be considered in the design of all precursor
steps to support, simplify, and enhance impact prediction.
The USCG DCR environmental evaluation (see Section 10.2 for a discus-
sion of background on the DCR EIS) presents an example similar to that of
Scituate in that the description of the affected environment was the major
input to impact prediction. Since the discharge of DCR had occurred for over
a century, the description of the affected environment was a critical input to
impact prediction for many environmental resources because the impact of
past DCR practices could be directly measured. The premise that a reduction
in DCR discharge would result in a proportionate reduction in impact to
many of the critical environmental resources was presented to and accepted
by stakeholders, including the expert advisory committee (equivalent to a
TAC). Thus the impact of all alternatives, which represented various levels
of DCR discharge reduction could be quantified and compared based on the
measured impact from past actions for many of the environmental resources.
Another commonly used approach for impact prediction that is simple
and efficient is reliance on prediction of impacts in similar environmental
impact analyses. For many types of projects, plans, and programs there have
been many analyses conducted representing a range of existing conditions
and magnitude of actions. The power industry has conducted environmen-
tal evaluations for thousands of projects ranging from multiunit nuclear
power plants to solar generation facilities and everything in between. For
many components of power generation, impact predictions methods have
been developed including:
r Thermal discharge of cooling water
r Non-ionizing radiation from transmission lines
r Bird strike risk from wind turbines
r Land use changes from transmission corridors