## Facts

- Federal and state agencies approved “Westway,” a proposed replacement of Manhattan’s West Side Highway involving extensive Hudson River landfill and related development.
- The U.S. Army Corps of Engineers issued a dredge-and-fill permit under Clean Water Act (CWA) § 404 and a permit under Rivers and Harbors Act § 10; the Federal Highway Administration (FHWA) approved the project and its environmental documentation.
- The final environmental impact statement (EIS) described the landfill area as a “biological wasteland.”
- Later information indicated the shallow-water area supported significant fish habitat, including juvenile striped bass; federal resource agencies objected and urged further analysis.
- The Corps declined to prepare a supplemental EIS and proceeded with the permits; environmental organizations and individuals sued under NEPA, the CWA, and the Rivers and Harbors Act.
- After a bench trial, the district court found NEPA violations tied to fisheries analysis, found the Corps’ CWA permitting decision defective, found a Rivers and Harbors Act § 10 violation, and entered an injunction with supervision measures; defendants appealed and plaintiffs cross-appealed.

## Issues

1. Whether NEPA required the Corps and FHWA to take a “hard look” at fisheries impacts and to prepare a supplemental EIS based on new, significant fisheries information.
2. Whether the Corps’ CWA § 404 permit decision complied with the § 404(b)(1) guidelines in light of the fisheries impacts and alternatives.
3. Whether the Corps violated Rivers and Harbors Act § 10 by authorizing the landfill project in navigable waters.
4. Whether the district court’s injunction and related supervision orders were within equitable authority, and whether the court could compel supplementation regardless of whether the agencies continued pursuing the permit.

## Decision

- The Second Circuit largely affirmed that the agencies’ fisheries analysis was inadequate under NEPA and that reconsideration was required before proceeding with the landfill project.
- The court affirmed that the Corps’ CWA § 404 decision was arbitrary and capricious to the extent it relied on the flawed fisheries assessment.
- The court reversed the finding of a Rivers and Harbors Act § 10 violation, holding the record did not support that claim.
- The court narrowed the required scope of supplementation, rejecting an order to update non-fisheries topics absent a showing of significant new information on those topics.
- The court generally upheld injunctive relief halting construction during lawful reconsideration, but modified the remedy to make a supplemental EIS conditional: it could not be compelled if the Corps chose not to pursue reissuance of the landfill permit.

## Legal Principles

- NEPA requires agencies to take a “hard look” at environmental consequences and to disclose them; courts review compliance under the APA “arbitrary and capricious” standard.
- A supplemental EIS is required when significant new circumstances or information relevant to environmental concerns bear on the proposed action or its impacts.
- The duty to supplement is issue-specific; agencies need not update every component of an EIS without a showing of significant new information on that subject.
- Where a CWA § 404 permitting judgment depends on environmental effects, an agency’s failure to reasonably assess key impacts can render the permitting decision arbitrary and capricious under the § 404(b)(1) framework.
- Injunctions may be used to halt project implementation pending NEPA compliance, but courts may not compel an agency to prepare a supplemental EIS if the agency elects not to proceed with the action requiring the permit.

## Conclusion

The Second Circuit required lawful reconsideration of Westway’s landfill approvals because the agencies failed to adequately investigate and disclose fisheries impacts and to supplement the EIS on that issue if they intended to proceed, while limiting supplementation to areas with significant new information, reversing the § 10 Rivers and Harbors Act violation, and narrowing the district court’s remedial orders to avoid compelling continued pursuit of the permit.


Sierra Club v. U.S. Army Corps of Eng’rs, 701 F.2d 1011 (2d Cir. 1983)