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2015 NPS NEPA Handbook
If there are no direct or indirect effects from an action on a particular resource, there
can be no cumulative effects on that resource from that action.
In order to accurately assess cumulative impacts, you will need to identify past,
present, and reasonably foreseeable future actions that affect the same resources as
the proposed action or alternatives. Past, present, and reasonably foreseeable future
actions are not limited to NPS actions, but could be actions taken or proposed by any
federal, state, or local government or a private entity, and are actions that are not
included in the proposal or alternatives under consideration. To be considered
under the cumulative analysis section of your EA or EIS, past actions should have
ongoing impacts that are presently occurring. Reasonably foreseeable future actions
include those federal and non-federal activities not yet undertaken, but sufficiently
likely to occur, that a decision maker should take such activities into consideration in
reaching a decision. This includes, but is not limited to, activities for which there are
existing decisions, funding, or proposals. Reasonably foreseeable future actions do
not include those actions that are highly speculative or indefinite (46.30).
For example, if there is a small sewage treatment plant proposed for your park unit
that would impact water quality by discharging treated wastewater into a river, the
scope of your impact analysis should include analysis of the incremental impacts of
past, present, and reasonably foreseeable future actions on water quality, combined
with the impact of your proposal. Suppose in this example that cattle ranching on
public land immediately upstream of the park has resulted in and continues to result
in impacts to the river’s water quality. Inside the park, future road construction
activities are expected to have impacts on the river’s water quality. Immediately
downstream of the park there is agricultural use on private land that contributes
additional impacts to the river’s water quality. These represent past, present, and
reasonably foreseeable future actions; although they are not part of the sewage
treatment plant proposal, their collective impact on the river’s water quality must
nonetheless be analyzed in combination with those of the plant in the cumulative
impact analysis performed as part of the NEPA review of the plant (1508.7;
1508.25(a)(2)).
It is important to note that past, present, and reasonably foreseeable future actions
are limited to human actions, meaning they are attributable to specific individuals or
entities. Naturally occurring incidents, such as storm events or floods, are not actions
per se and therefore the effects of these types of incidents should be considered as
part of the affected environment rather than as part of a cumulative impact analysis.
Similarly, changes to the environment that are not attributable to specific actions,
such as general urban encroachment or population growth, should be addressed as
part of the affected environment. [See Section 4.4: Describing the Affected
Environment.]
When characterizing cumulative impacts, it is generally not necessary to individually
list and analyze the effects of each past cumulative action. Rather, it is appropriate to
discuss them in sum. [See CEQ guidance: Guidance on the Consideration of Past
Actions in Cumulative Effects Analysis.] When describing cumulative impacts in an EA
or EIS, you should separate the cumulative impact analysis from the analysis of direct
and indirect impacts. While the cumulative impact analysis should include the same