203Conducting the Environmental Impact Analysis and Assessment
5.3.4.1 Impact Prediction Approach
Impact prediction for the DCR EIS had an advantage that most EIS scientic
investigations do not share. The practice of dry cargo sweeping has occurred in
the Great Lakes for over 100 years and any impact on ecological receptors from
DCR discharge has occurred and continues to occur with the continuing DCR
sweeping practice. Thus in this case measurement of existing conditions is an
excellent predictor of future impacts of various DCR management alternatives.
An impact hypothesis was proposed: the degree of impact was generally
proportional to the mass of DCR discharged. This hypothesis was tested
through literature review and discussions ...