18 CFR 1318.104: Reliance on existing environmental documents.

(a) TVA may rely on another Federal agency's EA or EIS (including an EA or EIS prepared by a Tribal, State, or local agency on behalf of a Federal agency), or a portion thereof, if TVA determines that TVA's proposed action is substantially the same or similar to the other agency's action, and the other agency's document meets the standards for an adequate statement or assessment under these procedures.

(b) In making this determination, TVA will consider whether the scope and analyses in the other agency's EA or EIS adequately address the TVA action. TVA will cite, briefly describe the content and relevance to the environmental document, and may make modifications that are necessary to render the relied-upon document, or portion thereof, fit for fulfilling NEPA analytic requirements for the action at hand. TVA will publish this determination and the EA or EIS relied upon and notify affected Federal, Tribal, State, and local agencies and other interested entities.

(c) TVA may supplement another agency's EA or EIS in accordance with § 1318.103.