Conducting the Environmental Impact Analysis and Assessment - Environmental Impact Analysis: Process and Methods - page 164

5.2 AffectedEnvironment
The description of the affected environment documents the conditions of
each critical resource as it exists prior to any activity implementing the
proposed action. The terms existing conditions or baseline conditions are
also used to identify the affected environment. However, the term affected
environment is used here because it emphasizes that an environmental
analysis should focus on the environmental resources that are potentially
affected and not all existing conditions. As illustrated in Figure 4.1, in the
“credit card” diagram, the affected environment is confined to the envi-
ronmental resources, which overlap with the various components of the
alternatives and do not include existing conditions unrelated or not poten-
tially altered by any alternative action under consideration. The follow-
ing sections describe the steps and approaches for addressing the affected
environment in a comprehensive environmental analysis, with the first
step determining which environmental resources comprise the affected
environment.
5.2.1 Environmental Resources Comprising the Affected Environment
One of the criticisms of the early environmental analyses was that they
were encyclopedic with little analysis or i interpretation of the data provided
to help decision makers understand the environmental consequences of
the proposed action and alternatives. The criticism arose because the early
documents were dominated by lists and detailed descriptions of condi-
tions such as biological species, water quality, geology, and climate. The
discussion of these resources dominated the description of the affected
environment, not necessarily because they might be affected by any of the
alternatives, but because there was data available and such descriptions
were within the comfort zone of the first environmental analysis practitio-
ners. The early environmental analysis teams had no experience, guidance,
or examples of how to conduct environmental analysis, so they reverted to
what they knew how to do as scientists: a detailed description of the most
obvious features.
As environmental analysis has matured with more guidance documents
and successful examples, it has become more focused. The focusing of
the analysis begins with the identification of the environmental resources
potentially at risk for inclusion in the description of the affected environ-
ment. Both technical and social scoping (see Sections 4.3.1 and 4.3.2) are
primary tools for identifying the resources at risk and inclusion in the
environmental impact analysis. The impact prediction conceptual model
(see Section 5.3) that hypothesizes where an impact could potentially occur
is critical for identifying the resources potentially at risk. There are other
tools that can be used, but the critical process is for the environmental