Since the 1970s, the National Environmental Protection Act (NEPA) has required agencies to take a “hard look” at infrastructure’s impact on the environment. However, as the climate crisis progresses, understanding the environment’s impact on infrastructure plays a key role in effective climate adaptation.
In Harrison County v. U.S. Army Corps of Engineers (Harrison County), Mississippi counties, cities, and associations asked the Fifth Circuit to compel the U.S. Army Corps of Engineers (Corps) to prepare a supplemental environmental impact statement (EIS) analyzing the impacts of climate change on the Bonnet Carré Spillway (the Spillway) near New Orleans. Increased incidents of extreme flooding in recent years have required the Corps to use the Spillway more regularly to divert water from the Mississippi River, resulting in severe environmental and economic impacts from the inundation of freshwater into local saltwater ecosystems. The plaintiffs argued NEPA regulations required a supplemental EIS as increased usage of the Spillway constituted a “major federal action” operating under “significant new circumstances” caused by climate change.
To decide Harrison County, the Fifth Circuit addressed the legal question of whether the Corps’ increased operation of the Spillway constituted a “major federal action,” despite no proposed or actual change to its operating procedures. The Fifth Circuit correctly answered no. Case law indicated that agencies do not have an obligation to prepare a supplemental EIS for completed projects. While the decision aligns with precedent, Harrison County is out of step with the urgent need for the Corps to incorporate climate change into its decision making. The case is a bright warning sign that NEPA’s prospective framing makes it an insufficient tool for compelling agencies to prepare climate analyses on existing infrastructure projects.
