Lake Oahe "a memorandum and an executive order asking USACE to expedite its consideration of the company’s application for an easement to start construction." The USACE subsequently "withdrew its call for the environmental study." On 7 February 2017, the USACE approved an easement through Lake Oahe. On 9 February 2017, the Cheyenne River Sioux filed the first legal challenge to the easement, citing an 1851 treaty and interference with the religious practices of the tribe. Lake Oahe Lake Oahe (oh-WAH'-hee) is a large reservoir behind Oahe Dam on the Missouri River; it begins in central South Dakota and continues north into North
Norris Dam State Park the Norris Project in the 1930s, is located a few miles south of the dam. Norris Dam State Park is located entirely within the Appalachian Ridge-and-Valley Range, which is characterized by narrow elongated ridges flanked by broad, fertile river valleys. The low rolling hills that dominate the park's terrain are underlain by sedimentary rocks— namely limestone, dolomite, shale, and sandstone— which were formed roughly 400-500 million years ago during the Paleozoic Era. Most of Norris Dam State Park is coated by an Appalachian oak-pine forest, much of which is second-growth, although significant old growth stands remain in nearby Chuck Swan