State of MI v. U.S. Army Corps of Eng’rs
Asian carp have migrated up the Mississippi River and are at the brink of the man-made Chicago-Area Waterway System path to the Great Lakes. The carp are dangerous to the eco-system, people, and property. States bordering the Lakes filed suit, alleging that the U.S. Army Corps of Engineers and the Metropolitan Water Reclamation District of Greater Chicago manage the system in a manner that will allow carp to move into the Great Lakes, in violation of the federal common law of public nuisance. The district court denied a preliminary injunction that would have required additional physical barriers, new procedures to stop invasive carp, and an expedited study of how best to separate the Mississippi and Great Lakes permanently. The Seventh Circuit affirmed. Plaintiffs presented enough evidence to establish a likelihood of harm, a non-trivial chance that carp will invade Lake Michigan in numbers great enough to constitute a public nuisance and that harm to the plaintiff states would be irreparable. The defendants have, however, mounted a full-scale effort to stop the carp and has promised that additional steps will be taken in the near future. This effort diminishes any role that equitable relief would otherwise play and an interim injunction would only get in the way.