Standing Rock Sioux Tribe v. U.S. Army Corps of Engineers

In 2017, the United States Army Corps of Engineers (the Corps) (defendant) granted an easement allowing construction of a portion of the Dakota Access Pipeline (the pipeline) under Lake Oahe, a manmade lake located in North Dakota and South Dakota. Prior to granting the easement, the Corps conducted an environmental assessment (EA) that concluded that the construction of the pipeline would not result in a significant environmental impact. After the Corps published its EA, several subject-matter experts submitted detailed reports strongly critiquing the EA’s data and methodology. The Corps considered but did not resolve the experts’ concerns before deciding to approve the easement without preparing an environmental-impact statement (EIS). The Standing Rock Sioux Tribe and the Cheyenne River Sioux Tribe (collectively, the tribes) (plaintiffs) sued the Corps in federal court. The tribes moved for summary judgment, arguing that the National Environmental Policy Act of 1969 (NEPA) required the Corps to prepare an EIS prior to approving the easement. The district court remanded the case to the Corps, ordering it to reconsider whether an EIS was necessary. One of the factors the Corps was directed to consider was whether the project’s effects were likely to be highly controversial. After completing its remand analysis, the Corps again determined that no EIS was necessary. Both the tribes and the Corps moved for summary judgment.