Flagstaff, AZ – A Federal Appeals Court has rejected arguments challenging National Park Service rules allowing commercial rafters to use motors on the Colorado River through Grand Canyon. Several environmental groups sued the park service in 2006 over its Colorado River management plan that allowed the sue of motorized rafts. The groups argued that the park service ignored its own rules that say use of the canyon shouldn't impair the wilderness quality of the area. The environmental groups favored the phase-out of motorized boats. However, the 9th Circuit Court of Appeals rejected that argument yesterday, saying the plaintiffs failed to show that the park service acted arbitrarily when adopting the river management plan.