Conducting the Environmental Impact Analysis and Assessment - Environmental Impact Analysis: Process and Methods - page 187

electricity. The potential impact then proceeds through nodes again similar to
the nodes of switches, fuses, and lights in a wiring diagram. The nodes in an
impact prediction conceptual model might be environmental attributes such
as a specific water body, assimilative capacity of the water body, or the aquatic
organisms in the receiving waters, which could be the impact receptor.
An impact prediction conceptual model for a proposed multiuse land
development (e.g., condominiums, elderly housing, retail stores, and recre-
ational facilities) on existing agricultural land could be quite complex. The
potential impact would be initiated at the site by factors such as development
layout and area of each specific land use. A section of the impact predic-
tion model would be developed for each area of impact such as traffic, noise,
visual aesthetics, utilities, community services, wildlife habitat, and storm
water. The conceptual model in each section would then be constructed
showing the nodes between the source of impact and the receptor. For exam-
ple, the storm water section of the conceptual model would show the source
of impact as the roof and paved areas generating runoff. Landscaped areas
might also be a potential impact source due to fertilizers and pesticides and
the potential impact receptors would be aquatic biota, recreational users, and
raw drinking water supply. The pathways and nodes in the model would
include water quality and quantity of runoff, storm water conveyance system
(including any proposed treatment or infiltration systems), quality and quan-
tity of storm-water discharge, drinking water intakes in receiving waters,
recreational areas in receiving water, and water quality/aquatic biota condi-
tions in receiving waters. First, the investigation of the affected environment
and then the impact prediction and quantification would focus on each node,
and the impact conceptual model would be reviewed and revised as war-
ranted as each affected environment and impact evaluation was completed.
If the evaluation of drinking water sources revealed no sources downstream
of the storm water runoff or no discharge points for the development, the
path of impact to potable water would not be completed and no additional
investigation of impact to drinking water would be necessary. For areas of
impact that illustrate completed pathways, analyses must be designed and
implemented to quantify the transfer among nodes to determine impacts.
The impact prediction conceptual model is an enhancement of the frequently
used environmental checklists (Eccleston 2008) as a critical step in the impact
prediction process. At its most basic level, the environmental checklist is a
generic compilation of all possible environmental resources, both natural (e.g.,
water quality, terrestrial wildlife, endangered species) and built (e.g., traffic,
community services, and infrastructure), that could conceivably be affected by
any type of project in any location. The list is then reviewed in light of the alter-
natives and the resources potentially at risk are checked on the list. At a more
detailed level, the single-column check list can be expanded to a matrix, with
the resources on one axis and the type of activity (e.g., construction, operation,
wastewater discharge) on the other axis. The checklists are designed as a tool
for preparing environmental analyses to facilitate identification of potential