The US National Park Service (NPS) manages the Grand Canyon National Park in Arizona under a management plan that is subject to periodic reviews. In 2006, after nine years of background work and of completion of comprehensive environmental impact statement, the NPS issues a new management plan for the park. The plan allowed of continued use of rafts on the Colorado river, which runs through the Grand Canyon. The number of rafts was limited however. Several environmental groups criticized the plan because they felt that it still allowed too many rafts on the river. The groups ask the federal court to overturn the plan, claiming that it violated the wilderness status of the national park. When can a federal court overturn a determination by an agency such as NPS? Explain.