23 C.F.R. § 777.7 – Evaluation of impacts.

(a) The reasonableness of the public expenditure and extent of Federal participation with title 23, U.S. Code, funds shall be directly related to:
1. (1) The importance of the impacted wetlands and natural habitats;
2. (2) The extent of highway impacts on the wetlands and natural habitats, as determined through an appropriate, interdisciplinary, impact assessment; and
3. (3) Actions necessary to comply with the Clean Water Act, Section 404, the Endangered Species Act of 1973, and other relevant Federal statutes.
(b) Evaluation of the importance of the impacted wetlands and natural habitats shall consider:
1. (1) Wetland and natural habitat functional capacity;
2. (2) Relative importance of these functions to the total wetland or natural habitat resource of the area;
3. (3) Other factors such as uniqueness, esthetics, or cultural values; and
4. (4) Input from the appropriate resource management agencies through interagency coordination.
(c) A determination of the highway impact should focus on both the short-and long-term affects of the project on wetland or natural habitat functional capacity, consistent with 40 CFR part 1500, 40 CFR 1502.16, 33 CFR 320.4, and the FHWA's environmental compliance regulations, found at 23 CFR part 771.