## Facts

- Riverside Irrigation District and Public Service Company of Colorado proposed constructing the Wildcat Dam and Reservoir on Wildcat Creek, a tributary of the South Platte River in Colorado.
- The project required discharging dredged or fill material into waters subject to regulation under Clean Water Act (CWA) § 404, which can be authorized either by a nationwide permit (if conditions are met) or an individual permit (with public notice and review).
- Corps regulations limited nationwide permits where the activity would jeopardize endangered species or adversely modify designated critical habitat under the Endangered Species Act (ESA).
- The U.S. Army Corps of Engineers concluded that the reservoir would facilitate increased consumptive use of stored water, causing foreseeable downstream depletions in the South Platte system.
- The Corps determined those depletions would adversely affect designated whooping crane critical habitat and therefore informed plaintiffs the project did not qualify for a nationwide permit and must proceed, if at all, through an individual § 404 permit application.
- Plaintiffs sought declaratory and injunctive relief, arguing the Corps exceeded its authority by considering indirect downstream effects tied to post-impoundment water use.

## Issues

1. Whether the Corps exceeded its authority under CWA § 404 and applicable regulations, informed by the ESA, by denying nationwide-permit coverage based on foreseeable downstream flow depletions affecting endangered-species critical habitat.
2. Whether the Corps may consider indirect and downstream environmental consequences related to a dredge-and-fill activity when determining eligibility for a nationwide permit.

## Decision

- The Tenth Circuit affirmed the district court’s judgment upholding the Corps’ determination.
- The court held the Corps did not exceed its statutory or regulatory authority by considering downstream effects, including flow depletions associated with increased consumptive use facilitated by the reservoir.
- The court agreed that ESA-based conditions applicable to nationwide permits permitted (and required) denial of nationwide-permit coverage where critical habitat would be adversely affected.
- The ruling required only that the proponents seek an individual § 404 permit; it did not bar the project outright.

## Legal Principles

- The Corps may deny nationwide-permit coverage and require an individual CWA § 404 permit when nationwide-permit conditions are not satisfied, including conditions protecting endangered species and critical habitat.
- In evaluating nationwide-permit eligibility, the Corps may account for reasonably foreseeable indirect and downstream environmental effects that bear a sufficient relationship to the regulated discharge and the overall project.
- ESA obligations may be integrated into CWA § 404 permitting decisions at the nationwide-permit screening stage, not solely during individual-permit review.
- Courts generally defer to an agency’s reasonable interpretation of its own regulations when consistent with the governing statutes.

## Conclusion

The Tenth Circuit upheld the Corps’ refusal to allow Wildcat Dam’s dredge-and-fill work to proceed under a nationwide permit because the Corps could consider foreseeable downstream flow depletions and their adverse effect on whooping crane critical habitat, requiring the proponents to pursue an individual § 404 permit instead.


Riverside Irrigation Dist. v. Andrews, 758 F.2d 508 (10th Cir. 1985)