651.16—Cumulative impacts.
(a)
NEPA analyses must assess cumulative effects, which are the impact on the environment resulting from the incremental impact of the action when added to other past, present, and reasonably foreseeable future actions. Actions by federal, non-federal agencies, and private parties must be considered ( 40 CFR 1508.7 ).
(b)
The scoping process should be used to identify possible cumulative impacts. The proponent should also contact appropriate off-post officials, such as tribal, state, county, or local planning officials, to identify other actions that should be considered in the cumulative effects analysis.
(1)
Identify the boundary of each resource category. Boundaries may be geographic or temporal. For example, the Air Quality Control Region (AQCR) might be the appropriate boundary for the air quality analysis, while a watershed could be the boundary for the water quality analysis. Depending upon the circumstances, these boundaries could be different and could extend off the installation.
(2)
Describe the threshold level of significance for that resource category. For example, a violation of air quality standards within the AQCR would be an appropriate threshold level.
(3)
Determine the environmental consequence of the action. The analysis should identify the cause and effect relationships, determine the magnitude and significance of cumulative effects, and identify possible mitigation measures.