45 CFR 900.405: Proposals normally requiring an EIS.

An EIS will normally be required for:

(a) Large scale infrastructure construction efforts such as the relocation of an entire community;

(b) A project that requires a formal consultation under Section 7 of the Endangered Species Act; or

(c) Where implementation of the proposal may directly cause or induce changes that significantly:

(1) Displace population;

(2) Alter the character of existing residential areas; or

(3) Adversely affect a floodplain.