Conducting the Environmental Impact Analysis and Assessment - Environmental Impact Analysis: Process and Methods - page 186

analysis. But impact prediction is typically the greatest technical challenge of
the analysis and provides the requisite answers and input to decisions.
Forecasting the condition of numerous natural and built environment
resources following construction and operation of facilities or infrastructure,
or implementing of a policy or regulation, is no simple task. If one could accu-
rately and simply know the future outcome of one's actions, not only envi-
ronmental conditions but also human history would be quite different. But
the challenge of predicting impacts to the extent practicable is the essence of
environmental analysis and why it is so critical. Thus the challenge is to make
the best prediction possible as to the condition of each critical environmental
resource following implementation of an alternative given the funding, time,
technical expertise and methods available. Added to this not so simple chal-
lenge is the necessity to focus on the critical resources where impact is most
likely to occur and expending resources in proportion to the magnitude and
likelihood of impact. This section presents available approaches to meet the
challenge and case studies where the challenge has been successfully met,
and others where the effort has fallen short.

5.3.1 Impact Prediction Conceptual Model

5.3.1.1 Model Development

The first step in predicting impacts for any alternative, for any purpose and
need, is the development of an impact prediction conceptual model, quali-
tatively evaluating and illustrating where impacts could potentially occur.
Developing this model involves predicting the consequences of an action
through a number of steps beginning with a proposed activity and terminat-
ing with an impact receptor (e.g., fish spawning, traffic patterns, or National
Park visitors). One of the final goals of environmental impact assessment and
analysis is to quantify, to the extent practical, each sequential cause/effect step
in the conceptual model to determine probability, magnitude and extent of the
changed conditions for the receptor. Before significant amounts of energy, time,
and funds are spent for the detailed investigations and models needed to quan-
tify impacts, it is important to confirm that the impact could possibly occur.
The impact prediction conceptual model is essential in making the determina-
tion of likely occurrence of an impact. The conceptual model also forms criti-
cal input to the planning of the affected environment investigation because it
identifies the resources that must be addressed and helps identify the intensity
and level of detail required for each environmental resource at risk.
The impact prediction conceptual model can be considered comparable to a
computer program logic flow or a wiring diagram. The model can take a num-
ber of forms from the simple to the complex and are sometimes considered
“casual networks” (Perdicoulis and Glasson 2006). In the conceptual model or
casual network each potential impact is initiated with some aspect of the pro-
posed action or alternative, just as a wiring diagram begins at the source of the