FIG. 2.1.2 Public participation in environmental impact assessment.
• Reparable via management practices or irreparable
• Short term or long term
• Temporary or continuous
• Construction or operational phase
• Local, regional, national, or global
• Accidental or planned (recognized beforehand)
• Direct or primary, or indirect or secondary
• Cumulative or single
Two key terms from the categories are direct or indirect, and cumulative; their definitions are as follows (Council on Environmental Quality 1987):
Effects (or impacts): These terms can be considered as synonymous. Two broad categories of effects are direct and indirect. Direct effects are caused by the action and occur at the same time and place. Indirect effects are caused by the action and occur later or farther removed in distance, but are still reasonably foreseeable. Indirect effects may include growth-inducing effects and other effects related to induced changes in the pattern of land use, population density or growth rate, and related effects on air and water and other natural systems, including ecosystems. Effects include ecological (such as the effects on natural resources and on the components, structures, and functioning of affected ecosystems), aesthetic, historic, cultural, economic, social, or health, whether direct, indirect, or cumulative. Effects also include those resulting from actions which may have both beneficial and detrimental effects, even if on balance the agency believes that the effect will be beneficial. Cumulative impact: The impact on the environment which results from the incremental impact of the action when added to other past, present, and reasonably foreseeable future actions regardless of what agency (federal or nonfederal) or person undertakes such other actions. Cumulative impacts can result from individually minor, but collectively significant, actions taking place over a period of time.
Based on these categories of impacts, several simple to more structured options can be used to determine impact significance. At a minimum, the definition of significantly in the CEQ regulations could be applied as described in the previous section.
A sequenced approach for impact significance determination is appropriate. A sequenced approach considers several levels in determining the potential significance of impacts from a proposed federal action. A sequenced approach is achieved by applying the following questions in the order shown (the answers to any question can be used to determine if an EIS should be prepared):
1. Does the proposed project, plan, program, or policy cause impacts that exceed the definition of significant impacts as contained in pertinent laws, regulations, or executive orders?
2. Is a quantitative threshold criterion exceeded in terms of project, plan, or program type, size, or cost?
3. Is the project, plan, or program located in a protected habitat or land-use zone, or within an exclusionary zone relative to land usage? Is the environmental resource to be affected a significant resource?
4. Is the proposed project, plan, program, or policy in compliance with environmental laws, regulations, policies, and executive orders?
5. What is the anticipated percentage change in environmental factors from the proposed project, plan, or program, and will the changes be within the normal variability of the factors? What is the sensitivity of the environment to the anticipated changes; or is the environment susceptible or resilient to changes? Will the carrying capacity of the resource be exceeded?
6. Are there sensitive human, living, or inanimate receptors to the environmental stresses from the proposed project, plan, program, or policy?
7. Can the anticipated negative impacts be mitigated in a cost-effective manner?
8. What is the professional judgment of experts in the substantive areas, such as water quality, ecology, planning, landscape architecture, and archaeology?
9. Are there public concerns due to the impact risks of the proposed project, plan, program, or policy?
10. Are there cumulative impacts which should be considered, or impacts related to future phases of the proposed action and associated cumulative impacts?
Detailed specific questions related to these ten groups of questions can be developed.
One thing that can be done in conjunction with identified significant negative impacts is to consider appropriate mitigation measures to reduce negative impacts within reasonable environmental and economic constraints. Relative to practice in the United States, mitigation includes (Council on Environmental Quality 1987):
1. Avoiding the impact altogether by not taking a certain action or parts of an action
2. Minimizing impacts by limiting the degree or magnitude of the action and its implementation
3. Rectifying the impact by repairing, rehabilitating, or restoring the affected environment
4. Reducing or eliminating the impact over time by preservation and maintenance operations during the life of the action
5. Compensating for the impact by replacing or providing substitute resources or environments
These measures should be used in sequence or ease of application, beginning with avoiding the impact.
Negative impacts fall into three categories: insignificant, significant but mitigable, or significant but not mitigable. When potentially significant negative impacts are identified, and if they can be reduced via mitigation to something of lesser concern, a mitigated FONSI can be prepared following an EA and without doing a comprehensive study leading to an EIS. However, a mitigated FONSI is possible only if the mitigation requirements are delineated to ensure that the identified measures are implemented.
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