50 CFR 402.17 – Other provisions
(a) Activities that are reasonably certain to occur. A conclusion of reasonably certain to occur must be based on clear and substantial information, using the best scientific and commercial data available. Factors to consider when evaluating whether activities caused by the proposed action (but not part of the proposed action) or activities reviewed under cumulative effects are reasonably certain to occur include, but are not limited to:
(1) Past experiences with activities that have resulted from actions that are similar in scope, nature, and magnitude to the proposed action;
(2) Existing plans for the activity; and
(3) Any remaining economic, administrative, and legal requirements necessary for the activity to go forward.
(b) Consequences caused by the proposed action. To be considered an effect of a proposed action, a consequence must be caused by the proposed action (i.e., the consequence would not occur but for the proposed action and is reasonably certain to occur). A conclusion of reasonably certain to occur must be based on clear and substantial information, using the best scientific and commercial data available. Considerations for determining that a consequence to the species or critical habitat is not caused by the proposed action include, but are not limited to:
(1) The consequence is so remote in time from the action under consultation that it is not reasonably certain to occur; or
(2) The consequence is so geographically remote from the immediate area involved in the action that it is not reasonably certain to occur; or
(3) The consequence is only reached through a lengthy causal chain that involves so many steps as to make the consequence not reasonably certain to occur.
(c) Required consideration. The provisions in paragraphs (a) and (b) of this section must be considered by the action agency and the Services.