Conducting the Environmental Impact Analysis and Assessment - Environmental Impact Analysis: Process and Methods - page 184

the side-scan sonar system were in fact the result of DCR discharges, as
actual cargo such as taconite pellets (which are the preprocessed iron ore
transported on the Great Lakes) were apparent in the sediment samples
(Figure 5.9). The samples were also processed to determine the biological,
chemical, and physical properties of the sediments in the areas of DCR dis-
charge. These areas of historical DCR discharge would be the same areas of
future discharge because the Great Lakes carriers would follow the same
courses they have for decades; thus the investigation fully described the
affected environment with respect to sediments for all DCR management
alternatives. Comparison of conditions in discharge areas with similar areas
receiving no DCR discharge was also a critical input to predicting impacts
associated with the alternatives.

5.2.7 Affected Environment Investigation Summary

The description of the affected environment lays the foundation for the entire
environmental impact analysis. It is typically the component of the overall
environmental impact analysis that requires the most time and resources,
and generates the maximum data. It should also be the simplest or at least
most straightforward because it most often involves employing standard
research methods that are well established and familiar to the members
of the environmental analysis team with expertise in the environmental
resource under investigation. However, it is also the component of the analy-
sis most vulnerable to numerous pitfalls, including expending excessive time

FIGURE 5.9
Great Lakes sediment sample with discharged iron ore (taconite) dry cargo residue.