Black Warrior Riverkeeper and Defenders of Wildlife challenged the Army Corps of Engineers’ 2012 reissuance of Nationwide Permit 21, which authorized surface coal-mining projects to discharge dredged material or fill into U.S. waters. They alleged that the Corps violated the Clean Water Act and National Environmental Policy Act by treating the permit’s grandfathered projects as having only minimal cumulative environmental effects. The district court recognized standing but dismissed the challenge under laches and upheld the Corps’s determinations. The Eleventh Circuit held that the organizations had Article III standing because their members’ downstream recreational and aesthetic interests were sufficiently connected to the challenged authorizations. It also held that the delay was excusable and that the intervening coal companies had not shown the concrete, delay-caused prejudice required for laches. On the merits, the Corps conceded that it had underestimated the acreage affected by grandfathered projects, requiring reconsideration of its Clean Water Act and NEPA analyses. The court reversed the merits ruling and remanded for that reconsideration but declined to vacate the permit immediately because the record did not establish the error’s ultimate significance or the consequences of vacatur. Judge Totenberg concurred on standing and laches but dissented from remand without vacatur, reasoning that the admitted error required suspending the grandfathered authorizations.